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Colecalciferol

  • Dietary supplement
  • Varies by country
  • Identity checked
  • Sources last checked 2026-09-04

This page shows what was measured, who it was measured in, and what that does not settle.

What Colecalciferol does in the body

If you have too little, calcium absorption fails and your parathyroid glands start dismantling your skeleton to keep blood calcium normal.

Vitamin D from sun or a capsule is inert until the body activates it twice, first in the liver and then in the kidney. The finished hormone slots into a receptor inside cell nuclei and switches on the genes that let the intestine absorb calcium. Correcting that is what vitamin D unambiguously does. Adding more once the system is already saturated is a different proposition, and that is what the large trials tested.

Why people take it. Taken for bones and immunity, tested against most of that and failed

What happened in people

Serum 25-hydroxyvitamin D rises reliably and dose-dependently on supplementation, to 115 nmol/L on monthly dosing in D-Health

Source-linked record

Where this came from

A person wrote this into the record with the study named beside it. No reviewer has signed it off.

The recorded finding that sits closest to something a person would notice. Written into the record, not signed off, and it carries no population or interval.

The limit that matters most

The two survivors — autoimmune disease and respiratory infection — are modest, and the respiratory effect was not modified by baseline vitamin D status, which is difficult to reconcile with a repletion mechanism

Where it acts
Skin (synthesis), hepatocyte and renal proximal tubule (activation), intestinal enterocyte nucleus (action)
Kind of result
A number that stands in for health
Supervision
Not usually supervised: sold as a supplement or food ingredient where recorded. That is a legal category, not a safety judgement.

What the registries record it as

  • The substance registry classes this as chemical.

    FDA substance registry · 1C6V77QF41 · read 2026-08-29

  • The supplement label database classes it as vitamin, under the name Vitamin D3.

    NIH Dietary Supplement Label Database · 207 · read 2026-08-29

Where each sentence above came from

A person wrote this explanation into the record, with the studies named in the path below.

The recorded use, written for a reader without medical training. Not signed off.

A limit recorded against this substance. Not signed off as a reviewed claim.

The four opening statements run to 124 words.

Words this page uses

Four words worth knowing first

Chosen from what this page shows, with each one explained before the word it depends on.

Stand-in result

A stand-in result is a number measured because the real result takes too long.

A picture of it, and where the picture fails

It is like judging a journey by the speedometer rather than by arriving.

Where that stops being true. Speed does predict arrival. Many stand-in results do not predict the real one.

What people get wrong. A stand-in result is often reported as the result itself.

A surrogate endpoint substituted for a clinical endpoint, valid only where the substitution has been shown to hold.

Randomisation

Randomisation means chance decides who gets which treatment.

A picture of it, and where the picture fails

It is like a coin toss deciding the groups.

Where that stops being true. A coin toss is fair once. Fairness here comes from doing it for everyone.

What people get wrong. It is thought to make groups identical. It makes them similar on average, including on things nobody measured.

Allocation of participants to arms by a chance process, so that unmeasured factors are balanced in expectation.

Confidence interval

A confidence interval is the range the true answer is likely to sit in.

A picture of it, and where the picture fails

It is like a weather forecast giving a range rather than one number.

Where that stops being true. A forecast range covers tomorrow. This one covers what the study could resolve.

What people get wrong. The middle number is read as the answer. A range crossing zero means no change is still possible.

An interval estimate that would contain the true parameter in a stated proportion of repeated studies.

Pathway

A pathway is a chain of steps inside a cell, each one setting off the next.

A picture of it, and where the picture fails

A pathway is like a row of dominoes.

Where that stops being true. Dominoes fall one way. Pathways loop back and can switch themselves off.

What people get wrong. Changing one step is read as changing the outcome. Other steps often absorb it.

An ordered series of molecular interactions producing a defined cellular change.

What happened in peopleRead from sources, not yet reviewed

What was measured, goal by goal

One row for each goal a registered study measured something for. One column for each kind of thing that could be measured.

Registered studies list 40 outcome measures that RNAWiki could read. A registered study says what someone planned to measure. It does not say what they found. 0 of the matched studies tested this substance, and 0 posted a result.

There is no single score. A strong test result and a weak life result are different facts.

Goals down the side, kinds of measurement across the top. Each cell says what kind of thing was registered, not what was found.
GoalLife outcomeWhat a body can doHow a person feelsA test resultA step in the bodyHarmsHow longWho was studied
Blood sugarNothing in the sources checkedNo registered study lists a life outcome for this goal.Nothing in the sources checkedNo registered study lists a performance measure for this goal.Nothing in the sources checkedNo registered study lists a symptom measure for this goal.Only a number moved2 registered test measure.Nothing in the sources checkedNo registered study lists a body-step measure for this goal.Not recordedHarms were not a registered measure for this goal.Not recordedNo finished study window is recorded.Waiting for a reviewerWho was studied is listed further down the page.
Body weightNothing in the sources checkedNo registered study lists a life outcome for this goal.Nothing in the sources checkedNo registered study lists a performance measure for this goal.Nothing in the sources checkedNo registered study lists a symptom measure for this goal.Only a number moved2 registered test measure.Nothing in the sources checkedNo registered study lists a body-step measure for this goal.Not recordedHarms were not a registered measure for this goal.Not recordedNo finished study window is recorded.Waiting for a reviewerWho was studied is listed further down the page.
StrengthNothing in the sources checkedNo registered study lists a life outcome for this goal.Waiting for a reviewer1 registered performance measure of this kind.Nothing in the sources checkedNo registered study lists a symptom measure for this goal.Nothing in the sources checkedNo registered study lists a test result for this goal.Nothing in the sources checkedNo registered study lists a body-step measure for this goal.Not recordedHarms were not a registered measure for this goal.Not recordedNo finished study window is recorded.Waiting for a reviewerWho was studied is listed further down the page.
MoodNothing in the sources checkedNo registered study lists a life outcome for this goal.Nothing in the sources checkedNo registered study lists a performance measure for this goal.Nothing in the sources checkedNo registered study lists a symptom measure for this goal.Nothing in the sources checkedNo registered study lists a test result for this goal.Nothing in the sources checkedNo registered study lists a body-step measure for this goal.Not recordedHarms were not a registered measure for this goal.Not recordedNo finished study window is recorded.Waiting for a reviewerWho was studied is listed further down the page.
Healthy ageingWaiting for a reviewer1 registered study measure of this kind. No reviewed result yet.Nothing in the sources checkedNo registered study lists a performance measure for this goal.Nothing in the sources checkedNo registered study lists a symptom measure for this goal.Nothing in the sources checkedNo registered study lists a test result for this goal.Nothing in the sources checkedNo registered study lists a body-step measure for this goal.Not recordedHarms were not a registered measure for this goal.Not recordedNo finished study window is recorded.Waiting for a reviewerWho was studied is listed further down the page.
CholesterolNothing in the sources checkedNo registered study lists a life outcome for this goal.Nothing in the sources checkedNo registered study lists a performance measure for this goal.Nothing in the sources checkedNo registered study lists a symptom measure for this goal.Only a number moved1 registered test measure.Nothing in the sources checkedNo registered study lists a body-step measure for this goal.Not recordedHarms were not a registered measure for this goal.Not recordedNo finished study window is recorded.Waiting for a reviewerWho was studied is listed further down the page.
Which registered measures put each goal on this table
Blood sugar
insulin sensitivity; glycated hemoglobin; development of diabetes type 2
Body weight
body weight; body composition
Strength
muscle strength
Mood
depression
Healthy ageing
mortality
Cholesterol
ldl cholesterol

Sorted by fixed word lists, version v1. A name the rules do not recognise stays unsorted rather than moving to the nearest column.

What each mark on this table means
Nothing in the sources checked
No registered study lists a life outcome for this goal.
Only a number moved
2 registered test measure.
Not recorded
Harms were not a registered measure for this goal.
Waiting for a reviewer
Who was studied is listed further down the page.

What happened in peopleRead from sources, not yet reviewed

What happened in people

Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.

Radiologically confirmed hip and nonvertebral fractures over 18 months

The study showed what it set out to show

Who was studied
Chapuy 1992 (Decalyos) — vitamin D3 800 IU plus calcium in elderly women
How many people
3270
Study design
Randomised double-blind placebo-controlled
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
P = 0.043 for hip fracture (43% lower); P = 0.015 for nonvertebral fracture
Repeated elsewhere
Partially Replicated

What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.

The limits of this study, and where it came from

Main limit. Vitamin D3 was given with 1.2 g of elemental calcium, so the trial cannot separate the two. Mean age was 84 and participants were institutionalised with baseline secondary hyperparathyroidism.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral capsule, softgel, tablet or oil drops, cholecalciferol (D3) or ergocalciferol (D2)

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

Invasive cancer of any type, and major cardiovascular events

The study did not show it

Who was studied
NCT01169259 — VITAL, vitamin D3 2000 IU/day for cancer and cardiovascular disease
How many people
25871
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Cancer HR 0.96 (0.88-1.06), P = 0.47; major CVD HR 0.97 (0.85-1.12), P = 0.69
Repeated elsewhere
Replicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No excess hypercalcaemia or other adverse events. Participants were not selected for vitamin D deficiency, so the trial answers the general-population question rather than the deficiency question.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral capsule, softgel, tablet or oil drops, cholecalciferol (D3) or ergocalciferol (D2)

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

Incident total, nonvertebral and hip fractures, centrally adjudicated

The study did not show it

Who was studied
NCT01704859 — VITAL fracture ancillary
How many people
25871
Study design
Phase 3 ancillary
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Total HR 0.98 (0.89-1.08) P = 0.70; hip HR 1.01 (0.70-1.47) P = 0.96
Repeated elsewhere
Replicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No effect modification by baseline 25(OH)D, age, sex, race or BMI — the subgroup that a null vitamin D trial is usually rescued by was looked for and was absent.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral capsule, softgel, tablet or oil drops, cholecalciferol (D3) or ergocalciferol (D2)

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

All-cause mortality over five years

The study did not show it

Who was studied
ACTRN12613000743763 — D-Health, 60,000 IU monthly for mortality
How many people
21315
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
Living longer, or avoiding a major event
What was found
HR 1.04 (95% CI 0.93-1.18), P = 0.47
Repeated elsewhere
Replicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. Cancer mortality HR 1.15 (0.96-1.39); excluding the first two years of follow-up, 1.24 (1.01-1.54), P = 0.05. The authors invoked the precautionary principle against this regimen in replete people.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral capsule, softgel, tablet or oil drops, cholecalciferol (D3) or ergocalciferol (D2)

Interval reported. 95% CI 0

Written into the record, not signed off as a reviewed claim.

Six co-primary endpoints: systolic and diastolic blood pressure, SPPB, MoCA, nonvertebral fractures, infection rate

The study did not show it

Who was studied
NCT01745263 — DO-HEALTH, vitamin D3, omega-3 and exercise in older adults
How many people
2157
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
No endpoint reached the prespecified P < .01 with 99% confidence intervals
Repeated elsewhere
Replicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. A three-way factorial design across eight arms means each pairwise comparison is modestly powered, but no endpoint showed a signal in any direction.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral capsule, softgel, tablet or oil drops, cholecalciferol (D3) or ergocalciferol (D2)

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

Total volumetric bone mineral density and bone strength at radius and tibia over three years

The study did not show it

Who was studied
NCT01900860 — Calgary dose-ranging trial of volumetric bone density
How many people
311
Study design
Randomised double-blind dose-comparison
Compared against
Not recorded for this study
Kind of result
Measured performance
What was found
Radial vBMD change -1.2% (400 IU), -2.4% (4000 IU), -3.5% (10,000 IU); no significant difference in failure load
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. The higher doses were significantly worse than 400 IU on the co-primary density endpoint. Bone strength did not differ, so the clinical meaning of the density loss is unsettled.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral capsule, softgel, tablet or oil drops, cholecalciferol (D3) or ergocalciferol (D2)

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

What we know
RNAWiki holds 6 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.

What happened in peopleRead from sources, not yet reviewed

How close this is to real life

The top step is something a person would feel or care about. The bottom is a guess from software. Filled steps are where evidence exists for this substance.

  1. Living longer, or avoiding a major event Evidence recorded. Death, a heart attack, a stroke, a hospital stay.1 registered measure of this kind. No reviewed result.
  2. What a body can do day to day Evidence recorded. Walking, dressing, breathing, recovering.1 registered measure of this kind.
  3. Measured performance Evidence recorded. How much was lifted, how far was run, how fast.1 registered measure of this kind.
  4. Symptoms and quality of life No evidence recorded. Pain, tiredness, mood, sleep, as the person rated it.No registered study measures this.
  5. A number that stands in for health Evidence recorded. Cholesterol, blood sugar, bone density. A stand-in, not the thing itself.13 registered measures of this kind.
  6. A step measured inside a person Evidence recorded. Something measured in human tissue or human cells.A human record sits on the stored organism ladder.
  7. Animals Evidence recorded. Mice, rats, dogs. Useful for ideas, not proof about people.Stored records in C. elegans (roundworm), Mouse, Rat, Non-human primate. A result in animals says what to test next. It does not say what happens in people.
  8. Cells in a dish Evidence recorded. Cells or chemistry on a bench, far from a whole body.Stored mechanism abstracts describe steps measured in cells or tissue.
  9. A guess from software No evidence recorded. Nobody measured it. RNAWiki never publishes one as a finding.RNAWiki stores no prediction for this record. Software can suggest a link. RNAWiki does not publish one as a finding.

Higher on these steps means closer to something a person would feel. It does not mean better done.

What it changes in the bodyRead from sources, not yet reviewed

The path through the body

From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.

  1. Start

    Colecalciferol

    What a person takes: Oral capsule, softgel, tablet or oil drops, cholecalciferol (D3) or ergocalciferol (D2).

    The measurement behind this step

    Sold in the United States as a dietary supplement under DSHEA with no premarket efficacy review, and simultaneously present as a mandatory or voluntary fortificant in milk, cereal and margarine in most industrialised countries. D3 raises and maintains serum 25(OH)D more effectively than D2. It is fat-soluble, so absorption depends on a fat-containing meal and on intact bile flow.

  2. Getting in

    Made in skin or swallowed, and inert either way

    Ultraviolet light splits a cholesterol relative in the skin to make vitamin D3, and a capsule supplies the same molecule. Neither does anything yet.

    Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.

    The measurement behind this step

    UVB at 290 to 315 nm opens the B ring of 7-dehydrocholesterol to previtamin D3, which thermally isomerises to cholecalciferol. The reaction is self-limiting: continued irradiation converts previtamin D3 to inert lumisterol and tachysterol, so cutaneous synthesis cannot cause toxicity. Oral cholecalciferol is absorbed with dietary fat into chylomicrons and reaches the liver bound to vitamin D binding protein.

  3. Reaching the cell

    The liver adds the first hydroxyl, creating the storage form

    The liver converts it into the form that circulates for weeks and that a blood test measures. This is still not the active hormone.

    Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.

    The measurement behind this step

    Hepatic CYP2R1, with minor contributions from CYP27A1, 25-hydroxylates cholecalciferol to 25-hydroxyvitamin D3. This step is only loosely regulated, which is why serum 25(OH)D tracks intake and why it is the status marker, with a circulating half-life of two to three weeks against hours for the active hormone.

  4. What it acts on

    The kidney adds the second, tightly controlled, hydroxyl

    The kidney makes the final active hormone, and it does this only when parathyroid hormone tells it to. That control step is why swallowing more does not simply produce more hormone.

    Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.

    The measurement behind this step

    Renal proximal tubule CYP27B1 1-alpha-hydroxylates 25(OH)D3 to 1,25-dihydroxyvitamin D3. It is upregulated by parathyroid hormone and suppressed by FGF23 and by the product itself, while CYP24A1 simultaneously inactivates both substrate and product to 24,25- and 1,24,25-forms. The whole step is a homeostat, and a homeostat is exactly the kind of system that flattens a supplement dose-response.

  5. The change it makes

    The hormone binds a nuclear receptor and turns on calcium transport genes

    The finished hormone slots into a receptor inside the cell nucleus, which then switches on the genes the intestine needs to pull calcium out of food.

    Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.

    The measurement behind this step

    1,25-dihydroxyvitamin D3 binds the vitamin D receptor, which heterodimerises with retinoid X receptor and occupies vitamin D response elements. Induced genes include TRPV6 (apical calcium entry), CALB1 (cytosolic calcium ferrying), ATP2B1 (basolateral extrusion) and CYP24A1 (its own catabolism). The receptor is expressed in far more tissues than intestine and bone, which is the origin of essentially every extra-skeletal hypothesis on this page.

  6. What that does for a person

    Calcium absorption rises, parathyroid hormone falls, bone mineralises

    With calcium absorption restored, the parathyroid glands stop stripping the skeleton, and new bone mineralises properly. That is the whole demonstrated benefit.

    Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.

    The measurement behind this step

    Restored intestinal calcium absorption raises ionised calcium, suppressing PTH secretion through the calcium-sensing receptor and halting osteoclastic resorption. Chapuy measured this directly: PTH fell 44% and femoral bone density rose 2.7% against a 4.6% fall on placebo. Where baseline PTH is already normal, as in VITAL and D-Health, there is no secondary hyperparathyroidism to suppress and no measured benefit follows.

No suggested links are held for this record, so nothing is hidden from this path.

What we know
The record describes 5 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.

What it would be like to takeRead from sources, not yet reviewed

Felt, measured, or meaningful

Three different things that get called the same word. Registered studies measured all three, and mixing them is how a blood test becomes a health claim.

Felt

Things a person could notice without a test.

No registered study measured anything of this kind.

Measured

Things only a test, a scale or a device shows.

  • bone mineral density in the lumbar spine
  • bone mineral density by test at 1 and 2 years
  • lumbar spine bone mineral density at 12 months
  • body weight
  • body composition
  • insulin sensitivity
  • muscle strength
  • blood pressure
  • 25 hydroxyvitamin d concentration
  • bone mineral density

and 4 more.

Meaningful

Things that change how a life goes, not only a number.

  • mortality

A registered study says what someone planned to measure. It does not say what they found. A number moving is not the same as a life going better. The two are shown apart here.

Felt, but not shown to help. A person notices a change. No study showed it leads anywhere good.

Measured, but not felt. A number moves. The person notices nothing. Both can be true.

Measured, but not shown to matter. A number moves in the good direction. Nobody showed that lives went better.

Matters, but takes years. The result that counts may take longer than anyone would keep watching.

Names that fit none of the three (25)
  • complete response rate
  • lumbar spine bmd at 24 months
  • lumbar spine bmd at 36 months
  • lumbar spine bmd at 60 months
  • lumbar spine bmd at 120 months
  • colorectal adenomas
  • depression
  • acr20
  • vitamin d ria and hplc
  • parathyroid hormone ipth and 3rd generation ria
  • 25 hydroxyvitamin d
  • time to convert from sputum positivity to negativity
  • physical performance
  • base study + first extension rate of adverse events
  • second extension number of who experienced an adverse event
  • rate of falls
  • that experienced an adverse event
  • that discontinued study drug due to an ae
  • parathyroid hormone
  • bone density

These are harms, study-process measures, or names the rules did not recognise. They are shown rather than dropped.

What is missing or unclearRead from sources, not yet reviewed

Were people like you studied?

RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.

Who was studied

People similar to this profile were included.

  • Almost everyone, at some point. Also legitimately prescribed for documented deficiency, for malabsorption, after bariatric surgery, in chronic kidney disease and alongside anti-osteoporosis drugs.

Who is missing from the studies

  • Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.

Where the result stopped carrying

  • The "the dose was too low" defence: 500,000 IU annually increased falls and fractures, and three years at 4000 or 10,000 IU daily lowered radial bone density dose-dependently
  • Assay comparability, which was bad enough that the Vitamin D Standardization Program had to be created and which contaminates the older prevalence literature
  • The prediabetes hypothesis: D2d found HR 0.88 (0.75-1.04) at 4000 IU/day, in the predicted direction and not significant
  • This is a scope explorer, not a diagnosis engine.
  • It shows who was studied so you can see whether people similar to you were included.

RNAWiki cannot tell whether a study fits you. It can show who was in it.

What it would be like to takeRead from sources, not yet reviewed

Why it might seem to do nothing

A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.

It was studied for a different goal

The studies measured something else entirely.

On this record: Some registered studies measured things that match no goal on this page.

It was studied in different people

The people in the studies were not much like the reader.

On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.

There was nothing to correct

Where a level is already normal, topping it up may change nothing.

On this record: Vitamin D remains a genuine treatment for a genuine deficiency disease, and food fortification is one of the most successful public health interventions ever run

The evidence may simply be wrong

Small early studies often do not hold up.

On this record: RNAWiki has not yet published a reviewed conclusion for this use.

The product may not be what it says

Contents of a sold product are not always what the label states.

On this record: This is sold as a supplement, so no agency checked what is in a given tub before it was sold.

Other reasons RNAWiki checked and found nothing for (8)
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.

None of these is a reason to take more. Taking more is not a step this page ever suggests.

What it would be like to takeRead from sources, not yet reviewed

What taking it involves

The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.

How it is supplied

Varies by country

Quoted from a source

Where this came from

Copied from a source RNAWiki stored, with the source named.

Read from the recorded approval status.

No source is stored against this line.

Form and route

Oral capsule, softgel, tablet or oil drops, cholecalciferol (D3) or ergocalciferol (D2)

Source-linked record

Where this came from

A person wrote this into the record with the study named beside it. No reviewer has signed it off.

The form and route recorded on this substance.

No source is stored against this line.

Who oversees it

Not usually supervised: sold as a supplement or food ingredient where recorded. That is a legal category, not a safety judgement.

Quoted from a source

Where this came from

Copied from a source RNAWiki stored, with the source named.

The identity record classes it as a supplement ingredient; no medicines register records an approval.

No source is stored against this line.

What is in the pack

Sold in the United States as a dietary supplement under DSHEA with no premarket efficacy review, and simultaneously present as a mandatory or voluntary fortificant in milk, cereal and margarine in most industrialised countries.

Source-linked record

Where this came from

A person wrote this into the record with the study named beside it. No reviewer has signed it off.

Recorded notes on how this is sold. The rest of the recorded wording: D3 raises and maintains serum 25(OH)D more effectively than D2. It is fat-soluble, so absorption depends on a fat-containing meal and on intact bile flow.

No source is stored against this line.

Where it is registered

Regulatory records are listed in the technical disclosure at the foot of this page.

Counted from records

Where this came from

A count of rows RNAWiki holds. It describes our records, not your body.

Register entries are stored per jurisdiction and shown with their dates.

No source is stored against this line.

Why people stop

Not recorded.

Nothing recorded

Where this came from

RNAWiki holds nothing here and says so rather than guessing.

No record of why people stopped taking it is stored for this substance.

No source is stored against this line.

What it would be like to takeRead from sources, not yet reviewed

What can go wrong

Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.

Worth asking a clinician aboutWritten into the record from the studies named on this page

At ordinary intakes, well tolerated: VITAL found no excess hypercalcaemia at 2000 IU/day across 25,871 participants over five years. The risks appear at the extremes and in intermittent dosing. A single 500,000 IU annual dose increased falls (RR 1.15) and fractures (RR 1.26). Three years at 4000 or 10,000 IU daily lowered radial bone density dose-dependently. True toxicity — hypercalcaemia, hypercalciuria, nephrocalcinosis — requires sustained very high intake or a CYP24A1 loss-of-function mutation, and cannot be caused by sunlight, because cutaneous synthesis is self-limiting.

Nobody counted how many people took this and were fine, so this cannot be turned into a rate.

Where this came from

Reports sent to a regulator

  • These are reports people sent to a regulator. They do not show the medicine caused the reaction.
  • Nobody counted how many people took the medicine and reported nothing.
  • The same event can be reported more than once, and many reports are incomplete.
  • News coverage, lawsuits and new warnings change how often people report.
  • A count is not a rate and not a risk.

Colecalciferol appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 23937 reaction mentions were counted. One report can name several reactions.

The recorded terms (10)
  • pain — 3057 reaction mentions
  • alopecia — 2627 reaction mentions
  • fatigue — 2618 reaction mentions
  • abdominal discomfort — 2565 reaction mentions
  • systemic lupus erythematosus — 2532 reaction mentions
  • pemphigus — 2530 reaction mentions
  • rheumatoid arthritis — 2330 reaction mentions
  • glossodynia — 2063 reaction mentions
  • swelling — 1906 reaction mentions
  • hand deformity — 1709 reaction mentions
  • open-targets-adr · recorded 2026-06-24 · a recorded source, not a stored snapshot

Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.

Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.

What is missing or unclearNothing found in the sources checked

Does the exact form matter?

Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.

The form that was studied

Oral capsule, softgel, tablet or oil drops, cholecalciferol (D3) or ergocalciferol (D2)

Source-linked record

Where this came from

A person wrote this into the record with the study named beside it. No reviewer has signed it off.

The form used in the studies cited on this page.

No source is stored against this line.

What is sold

D3 raises and maintains serum 25(OH)D more effectively than D2. It is fat-soluble, so absorption depends on a fat-containing meal and on intact bile flow.

Source-linked record

Where this came from

A person wrote this into the record with the study named beside it. No reviewer has signed it off.

Recorded notes on which forms are sold and how they compare.

No source is stored against this line.

Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.

What it would be like to takeRead from sources, not yet reviewed

What you could measure

Watching one thing carefully can tell you whether it moved. It cannot tell you what moved it.

This is sold without a prescription, so a person can sensibly watch one thing and see whether it moves.

  1. Pick one goal. One goal only. Two at once cannot be told apart afterwards.

  2. Pick one thing to watch. Registered studies measured things like: bone mineral density in the lumbar spine; bone mineral density by test at 1 and 2 years; lumbar spine bone mineral density at 12 months.

  3. Measure before you start. Take the same measurement several times first. One reading is not a starting point.

  4. Know the swing. Write down how much it moves on its own across a normal week.

  5. Change one thing. Change nothing else at the same time, including training and sleep.

  6. Give it the study length. No finished study window is recorded, so no length is suggested here.

  7. Track whether you took it. Missed days are the most common reason a home test shows nothing.

  8. Read the trend. Look at the line across weeks. A single reading tells you almost nothing.

What not to measure

  • Anything that swings more day to day than the change you are looking for.
  • A wearable estimate of sleep stages, which is an estimate and not a measurement.
  • Weight on one morning, which mostly records water.
  • A feeling you did not write down before starting.

When to stop

  • Stop if something new and unpleasant starts, and ask a pharmacist or doctor.
  • Stop if you cannot keep everything else steady, because the result will not mean anything.
  • Stop at the end of the window you set, and read the trend then.

Tracking can show whether something changed for you. It cannot show what caused it.

RNAWiki does not work out an amount for anyone.

What is missing or unclearRead from sources, not yet reviewed

Claims that go past the evidence

Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.

Goes past the evidence

That vitamin D prevents cancer — 25,871 randomised participants, HR 0.96, P = 0.47

Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.

The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.

What would change this

A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.

RNAWiki has not yet published a reviewed conclusion for this use.

Goes past the evidence

That it prevents cardiovascular events — same trial, HR 0.97, P = 0.69

Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.

The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.

What would change this

A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.

RNAWiki has not yet published a reviewed conclusion for this use.

Goes past the evidence

That it prevents fractures in the general population — HR 0.98 total, 1.01 hip, with no subgroup effect by baseline level

Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.

The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.

What would change this

A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.

RNAWiki has not yet published a reviewed conclusion for this use.

Goes past the evidence

That it reduces mortality — 21,315 randomised participants, HR 1.04

Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.

The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.

What would change this

A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.

RNAWiki has not yet published a reviewed conclusion for this use.

Goes past the evidence

That the enormous observational literature reflects causation rather than 25(OH)D falling with illness, obesity and inactivity

Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.

The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.

What would change this

A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.

RNAWiki has not yet published a reviewed conclusion for this use.

What is missing or unclearRead from sources, not yet reviewed

What nobody knows yet

Open questions, each with why it is open and what would close it.

How fast does the body clear it?

The sources RNAWiki checked hold nothing for this field.

Why it matters. Without this, nothing on this page can say how long anything lasts.

What would answer it

A stored source that records it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Missing populations

Which groups were under-represented in the studies has not been recorded.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Missing long-term data

No completed tested study window is recorded.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

No reviewed conclusion

RNAWiki has not yet published a reviewed conclusion for this use.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Missing interaction studies

No interaction was found in the registers checked. Not finding one is not the same as showing there is none.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Formulation uncertainty

Several salts, forms or products of Colecalciferol are recorded. Results from one form may not transfer to another.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Mechanism not reviewed

No reviewed mechanism story exists for this substance.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

What happened in peopleRead from sources, not yet reviewed

Check any of this yourself

Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.

Every line above can be traced to the study named beside it. Follow the link and read it.

Chapuy 1992: hip fractures fell 43% — in 84-year-old deficient women
In plain words
In very old, frail, institutionalised French women with low vitamin D and overactive parathyroid glands, vitamin D3 with calcium cut hip fractures by nearly half. This is the real effect, in the real population.
What was measured
Radiologically confirmed hip and nonvertebral fracture incidence, serum PTH, 25(OH)D and femoral bone mineral density over 18 months
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Three thousand two hundred and seventy healthy ambulatory women with a mean age of 84 +/- 6 years received either 1.2 g of elemental calcium as tricalcium phosphate plus 800 IU of vitamin D3 daily, or double placebo, for 18 months. Among completers, hip fractures were 43% lower (P = 0.043) and total nonvertebral fractures 32% lower (P = 0.015). Mean serum parathyroid hormone fell 44% from baseline (P < 0.001) and 25-hydroxyvitamin D rose 162% (P < 0.001). Proximal femoral bone density rose 2.7% on treatment and fell 4.6% on placebo (P < 0.001). Every element of this result — the age, the institutional setting, the baseline secondary hyperparathyroidism, the co-administered calcium — is part of the finding and none of it transfers automatically to a replete 55-year-old.
Source
Chapuy MC et al. N Engl J Med 1992;327:1637-1642
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
verified
Review state
Written into the record, not signed off as a reviewed claim
VITAL: 25,871 people, 5.3 years, no effect on cancer or cardiovascular disease
In plain words
The largest randomised test of vitamin D for the two diseases it is most often sold against found nothing. Cancer risk was unchanged. Heart attack and stroke risk was unchanged. So was death from any cause.
What was measured
Incident invasive cancer and major cardiovascular events over a median 5.3 years
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
A nationwide two-by-two factorial randomised placebo-controlled trial of vitamin D3 2000 IU/day and marine n-3 fatty acids 1 g/day in 25,871 US adults (men 50 and over, women 55 and over, including 5,106 Black participants), median follow-up 5.3 years. Invasive cancer of any type: 793 cases on vitamin D against 824 on placebo, hazard ratio 0.96 (95% CI 0.88 to 1.06), P = 0.47. Major cardiovascular events: 396 against 409, hazard ratio 0.97 (95% CI 0.85 to 1.12), P = 0.69. Death from any cause across 978 deaths: hazard ratio 0.99 (95% CI 0.87 to 1.12). Secondary endpoints were uniformly null except a non-significant signal for death from cancer, hazard ratio 0.83 (95% CI 0.67 to 1.02). No excess hypercalcaemia. Participants were not selected for deficiency, which is both the trial's limitation and precisely the point: it tested the population that actually buys the product.
Source
Manson JE et al. N Engl J Med 2019;380:33-44
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
verified
Review state
Written into the record, not signed off as a reviewed claim
VITAL fractures: no effect on total, nonvertebral or hip fracture
In plain words
Vitamin D is recommended for bone health more than for anything else. Tested for fractures in the same 25,871 people, it made no difference — including in those who started with the lowest blood levels.
What was measured
Adjudicated incident total, nonvertebral and hip fractures
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The prespecified fracture ancillary study of VITAL confirmed 1,991 incident fractures in 1,551 participants over a median 5.3 years, adjudicated by centralised medical record review. Total fractures occurred in 769 of 12,927 on vitamin D3 and 782 of 12,944 on placebo: hazard ratio 0.98 (95% CI 0.89 to 1.08), P = 0.70. Nonvertebral fractures 0.97 (0.87 to 1.07), P = 0.50. Hip fractures 1.01 (0.70 to 1.47), P = 0.96. Critically, there was no modification of the treatment effect by baseline serum 25-hydroxyvitamin D concentration, age, sex, race or body-mass index — the subgroup rescue that is usually offered for a null vitamin D trial was tested for and was not there.
Source
LeBoff MS et al. N Engl J Med 2022;387:299-309
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
verified
Review state
Written into the record, not signed off as a reviewed claim
D-Health: 21,315 people, no mortality benefit, and a cancer-death signal the wrong way
In plain words
An Australian trial gave 21,315 older adults monthly vitamin D for five years. Deaths were not reduced. When the first two years were excluded, death from cancer was numerically higher on vitamin D.
What was measured
All-cause mortality over five years of monthly dosing, plus cause-specific mortality
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
A randomised double-blind placebo-controlled trial of 60,000 IU vitamin D3 monthly in 21,315 Australians aged 60 and over, median follow-up 5.7 years. Serum 25-hydroxyvitamin D reached 115 (SD 30) nmol/L on treatment against 77 (SD 25) on placebo, so the intervention plainly worked biochemically. All-cause mortality: 562 deaths (5.3%) on vitamin D against 538 (5.1%) on placebo, hazard ratio 1.04 (95% CI 0.93 to 1.18), P = 0.47. Cardiovascular mortality 0.96 (0.72 to 1.28). Cancer mortality 1.15 (0.96 to 1.39), P = 0.13. In an exploratory analysis excluding the first two years, cancer mortality was 1.24 (95% CI 1.01 to 1.54), P = 0.05. The authors wrote that the precautionary principle suggests this dosing regimen might not be appropriate in people who are already vitamin D-replete.
Source
Neale RE et al. Lancet Diabetes Endocrinol 2022;10:120-128
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
caution
Review state
Written into the record, not signed off as a reviewed claim
DO-HEALTH: six primary endpoints in 2,157 older adults, none met
In plain words
A European trial tested vitamin D, fish oil and strength training in every combination against six different health outcomes in older adults. Nothing worked, individually or together.
What was measured
Blood pressure, physical performance, cognition, nonvertebral fracture and infection incidence over three years
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
A double-blind placebo-controlled two-by-two-by-two factorial trial in 2,157 adults aged 70 and over without major health events in the preceding five years, randomised to 2000 IU/day vitamin D3, 1 g/day omega-3s and a home strength-training programme in eight combinations for three years. The six primary outcomes were change in systolic and diastolic blood pressure, Short Physical Performance Battery, Montreal Cognitive Assessment, and incidence rates of nonvertebral fractures and infections, with 99% confidence intervals and P < .01 required for significance. There were no statistically significant benefits of any intervention individually or in combination for any of the six endpoints. The largest observed effect was a 0.8 mm Hg difference in systolic blood pressure.
Source
Bischoff-Ferrari HA et al. JAMA 2020;324:1855-1868
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
verified
Review state
Written into the record, not signed off as a reviewed claim
The dose-response went into reverse: large intermittent doses caused falls
In plain words
For a decade the argument for null vitamin D trials was that the dose was too small. Then trials of very large doses found more falls, more fractures and lower bone density — not fewer.
What was measured
That the null results of vitamin D trials are explained by insufficient dosing, and that higher doses would therefore have worked
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Sanders et al. gave 2,256 community-dwelling women aged 70 and over a single annual oral dose of 500,000 IU cholecalciferol or placebo for three to five years. The vitamin D group had 171 fractures against 135 on placebo and fell at 83.4 per 100 person-years against 72.7, incidence rate ratio 1.15 (95% CI 1.02 to 1.30, P = .03) for falls and 1.26 (95% CI 1.00 to 1.59, P = .047) for fracture, with the excess concentrated in the three months after each dose. Separately, Burt et al. randomised 311 healthy adults aged 55 to 70 with normal baseline 25(OH)D to 400, 4000 or 10,000 IU daily for three years: radial volumetric bone mineral density fell by -1.2%, -2.4% and -3.5% respectively, a significant dose-dependent loss, with no difference in bone strength. The field's position moved from "the dose was too low" to a documented ceiling above which the direction of effect changes.
Source
Sanders KM et al. JAMA 2010;303:1815-1822; Burt LA et al. JAMA 2019;322:736-745
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
contested
Review state
Written into the record, not signed off as a reviewed claim
Two things did survive: autoimmune disease and, weakly, respiratory infection
In plain words
Out of an enormous randomised programme, two positive findings held up — a 22% reduction in new autoimmune disease, and a small reduction in respiratory infections at moderate daily doses.
What was measured
Medical-record-confirmed incident autoimmune disease; proportion of participants with one or more acute respiratory infections
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
In the VITAL autoimmune ancillary, confirmed incident autoimmune disease over a median 5.3 years occurred in 123 participants on vitamin D against 155 on placebo: hazard ratio 0.78 (95% CI 0.61 to 0.99, P = 0.05), a 22% reduction, with the omega-3 arm at 0.85 (0.67 to 1.08, P = 0.19), not significant. Separately, an aggregate-data meta-analysis of 46 randomised trials in 75,541 participants found a lower proportion of participants with one or more acute respiratory infections on vitamin D, odds ratio 0.92 (95% CI 0.86 to 0.99, 37 studies). The protection was seen with daily rather than bolus dosing (OR 0.78, 0.65 to 0.94), at 400 to 1000 IU daily equivalents (0.70, 0.55 to 0.89), and in participants aged 1 to 16 (0.71, 0.57 to 0.90) — but no significant interaction with dose, frequency or age was demonstrated, so those subgroups are hypothesis-generating rather than established. Notably, no effect was seen in any subgroup defined by baseline 25(OH)D concentration.
Source
Hahn J et al. BMJ 2022;376:e066452; Jolliffe DA et al. Lancet Diabetes Endocrinol 2021;9:276-292
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
verified
Review state
Written into the record, not signed off as a reviewed claim
The observational case rests on a marker that falls when you are ill
In plain words
Low vitamin D is associated with almost every disease studied. That is partly because being ill, inactive, obese or indoors lowers your vitamin D — not the other way round.
What was measured
That the very large body of observational associations between low 25-hydroxyvitamin D and disease reflects vitamin D causing the disease rather than the disease lowering vitamin D
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
25-hydroxyvitamin D is an acute-phase reactant that falls during systemic inflammation, is sequestered in adipose tissue so falls with obesity, and falls with reduced outdoor activity, which is itself a consequence of most chronic disease. That makes reverse causation and confounding the default explanation for any observational vitamin D association until a randomised trial says otherwise. The D2d trial supplies the cleanest worked example: 2,423 adults with prediabetes randomised to 4000 IU/day, an amount well above what observational data implied was needed, with a hazard ratio for progression to diabetes of 0.88 (95% CI 0.75 to 1.04, P = 0.12) — the direction observational work predicted, the magnitude it predicted, and not statistically significant.
Source
Pittas AG et al. (D2d Research Group). N Engl J Med 2019;381:520-530
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
caution
Review state
Written into the record, not signed off as a reviewed claim

Where else this substance is registered

CAS registry number
67-97-0
PubChem compound
5280795
RxNorm concept
2418

Checks this page had to pass

  • Passed

    Identity resolved

    no open identity hold

  • Passed

    No unresolved merge across substance families

    no quarantine open

  • Passed

    Every public sentence names a source

    The opening statement carries the origin: Written into the record, not signed off.

  • Not passed

    Trial roles classified for highlighted evidence

    No registered study is classified as testing this substance.

  • Passed

    No internal keys in reader text

    enforced by the copy-contract test over the rendered page

  • Passed

    Safety mode resolved

    The identity record classes it as a supplement ingredient; no medicines register records an approval.

  • Passed

    Canonical metadata present

    slug and display name present

What is missing or unclearRead from sources, not yet reviewed

What to learn next

Ordered by what would most change how you read this page, starting with what is easiest to misunderstand.

This order is fixed in code and does not count clicks or time on the page.

What is not here

5 questions this page could not answer

These sections were prepared and left out because there was nothing to put in them. They are listed rather than hidden, so the gaps in this record are visible.

  • How long anything takes — found nothing in the sources checked.
  • What it may clash with — found nothing in the sources checked.
  • Other ways to the same goal — found nothing in the sources checked.
  • How this medicine reached us — found nothing in the sources checked.
  • What changed on this page — found nothing in the sources checked.

The record as stored

The full record, for auditing

Everything above is built from what is below. This layer keeps the technical vocabulary, record identifiers and every stored row, so a reader who wants to check the page can.

The older medicine-wide conclusion held in this record

Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.

A genuine hormone precursor that genuinely cures a genuine deficiency disease, and which — tested at 2000 IU daily in 25,871 people for cancer and cardiovascular disease, in 21,315 for mortality, and in 25,871 for fractures — did not change any of them.

Recorded evidence blocks (13)

What did Colecalciferol's largest trial (25871 people) and its longest (16 years) measure?


25871 people in Colecalciferol's largest registered study, 16 years in its longest registered window, measuring Mortality. ClinicalTrials.gov · 2026-09-01

87 na, 71 phase2, 57 phase3, 40 phase4, 22 phase1, 5 early phase1, 3 na or unstated; NCT01169259; 2026-10. Last human test completed 2025, NCT01351805.

Interpretation These counts include studies where Colecalciferol was a comparison treatment, a background treatment or an exposure in an observational study, and the longest window may be a planned end date. Trial roles have not yet been classified for this record.

Show the evidence
  • na
    87
  • phase2
    71
  • phase3
    57
  • phase4
    40
  • phase1
    22
  • early phase1
    5
2 more recorded rows
  • na or unstated
    3
  • Last recorded human test NCT01351805
    2025-02

recorded 2026-09-01 · last checked 2026-09-04

From C. elegans to human: where has Colecalciferol shown lifespan?


C. elegans: lifespan, NHP: mechanism-only, mouse: lifespan, rat: mechanism-only and human: lifespan (266): the rungs where Colecalciferol has a recorded finding. Europe PMC and ClinicalTrials.gov · organism ladder · 2026-09-01

Interpretation Mortality — the recorded outcome words.

Yeast C. elegans lifespanDrosophila Mouse lifespanRat mechanism-onlyDog Non-human primate mechanism-onlyHuman lifespan
Show the evidence
  • C. elegans
    lifespan
  • NHP
    mechanism-only
  • mouse
    lifespan
  • rat
    mechanism-only
  • human NCT00415402
    lifespan; Mortality; 266

recorded 2026-09-01 · last checked 2026-09-04

27 of Colecalciferol's trials stopped: futility/efficacy, accrual/recruitment, funding/business, other?


futility/efficacy (2), accrual/recruitment (16), funding/business (3) and other (6): Colecalciferol's stop wording, clustered. ClinicalTrials.gov · 2026-09-01

"Closed by the research committee"; 27 of 266 registered studies

Show the evidence

Trial

  • NCT00058188
    terminated; "Closed by the research committee"
  • NCT00104806
    terminated; "sponsor discontinues support"
  • NCT00279461
    withdrawn; "Dr. Levy terminated from IU in December 2009. Indiana University has no record that this study was initiated prior to his termination."
  • NCT00470353
    terminated; "Withdrawn due to poor accrual/lack of funding"
  • NCT00621257
    terminated; "Maintenance phase outcome unattenable"
  • NCT00762918
    withdrawn; "Recruitment"
14 further recorded trials
  • NCT00788320
    withdrawn; "Inadequate enrollment"
  • NCT00870961
    terminated; "PI changed institutions and accrual was not completed."
  • NCT00974922
    terminated; "Administrative/Sponsor Business Decision - terminated - study was not completed"
  • NCT00996866
    terminated; "Enable to further recruit study subjects"
  • NCT01005095
    terminated; "Interim analysis showed that the odds for proving primary hypothesis are low."
  • NCT01046773
    terminated; "Low enrollment"
  • NCT01145703
    terminated; "Investigator terminated study due to low enrollment of eligible subjects"
  • NCT01170442
    terminated; "In adequate enrollment"
  • NCT01170468
    terminated; "inadequate enrollement"
  • NCT01198548
    terminated; "Lack of funding"
  • NCT01230307
    terminated; "Unable to recruit sufficient number of patients."
  • NCT01264874
    terminated; "poor accrual rate"
  • NCT01274104
    withdrawn; "PI resigned."
  • NCT01284907
    withdrawn; "No Participants"

recorded 2026-09-01 · last checked 2026-09-04

Human studies of Colecalciferol used 2400 IU Vitamin D3 (cholecalciferol) — over how long?


Human studies of Colecalciferol used "2400 IU Vitamin D3 (cholecalciferol)". ClinicalTrials.gov · 2026-09-01

14 recorded entries; human; orally, capsule; also "Vitamin D3 1000 IU", "Cholecalciferol supplementation (400 IU and 4000 IU)", "Cholecalciferol (Vitamin D3) 70 µg"

Show the evidence

human

  • NCT00412074
    2400 IU Vitamin D3 (cholecalciferol)
  • NCT00732758
    Vitamin D3 1000 IU
  • NCT00907270
    Cholecalciferol supplementation (400 IU and 4000 IU)
  • NCT01038453
    Cholecalciferol (Vitamin D3) 70 µg
  • NCT01067898
    Vigantol vitamin D3 (cholecalciferol) oil 20 000 IU/ml
  • NCT01170494
    orally; cholecalciferol 2000 IU orally daily
8 more recorded rows
  • human NCT01170494
    orally; Cholecalciferol 25000 IU orally every 2 weeks
  • human NCT01306656
    10,000 IU Vitamin D3
  • human NCT01325610
    capsule; Maximum D3, cholecalciferol, 10,000IU/capsule, 0.25mg USP, Pro-Pharma LLA, Kirksville, Mo
  • human NCT01349127
    20µg Vitamin D3
  • human NCT01349127
    20µg Vitamin D3 + 500 mg Calcium
  • human NCT01417351
    2,000 IU Vitamin D3
  • human NCT01477034
    capsule; Carlson Labs Vitamin D3 capsules (2,000/4,000 IU/capsule)
  • human NCT05018585
    Colecalciferol 2000 IU

recorded 2026-09-01 · last checked 2026-09-04

Did Colecalciferol move Horvath, and by how much?


Horvath: "After the adjustment of multi-covariates, vitamin D3 supplementation of 4,000 IU/d was associated with 1.85 years decrease in Horvath epigenetic aging compared with placebo (p value = .046), and 2,000 IU/d was associated with 1.90 years decrease in Hannum epigenetic aging (p value = .044)." Europe PMC · epigenetic clock search · 2019-01-01

1 recorded sentence; 2019; biomarker

Show the evidence
  • Horvath PMID 30256915
    2019; "After the adjustment of multi-covariates, vitamin D3 supplementation of 4,000 IU/d was associated with 1.85 years decrease in Horvath epigenetic aging compared with placebo (p value = .046), and 2,000 IU/d was associated with 1.90 years decrease in Hannum epigenetic aging (p value = .044)."

recorded 2019-01-01 · last checked 2026-09-04

Could one person measure Colecalciferol's effect on bone mineral density in the lumbar spine?


Bone mineral density in the lumbar spine: measured in Colecalciferol's trials.

Interpretation bone mineral density in the lumbar spine is the recorded endpoint.

Show the evidence

biomarkers

  • bone mineral density in the lumbar spine; 2026-09-01
  • bone mineral density by test at 1 and 2 years; 2026-09-01
  • complete response rate; 2026-09-01
  • lumbar spine bone mineral density at 12 months; 2026-09-01
  • lumbar spine bmd at 24 months; 2026-09-01
  • lumbar spine bmd at 36 months; 2026-09-01
14 more recorded rows
  • biomarkers
    lumbar spine bmd at 60 months; 2026-09-01
  • biomarkers
    lumbar spine bmd at 120 months; 2026-09-01
  • biomarkers
    colorectal adenomas; 2026-09-01
  • biomarkers
    body weight; 2026-09-01
  • biomarkers
    body composition; 2026-09-01
  • biomarkers
    insulin sensitivity; 2026-09-01
  • biomarkers
    muscle strength; 2026-09-01
  • biomarkers
    depression; 2026-09-01
  • biomarkers
    blood pressure; 2026-09-01
  • biomarkers
    acr20; 2026-09-01
  • biomarkers
    vitamin d ria and hplc; 2026-09-01
  • biomarkers
    parathyroid hormone ipth and 3rd generation ria; 2026-09-01
  • biomarkers
    25 hydroxyvitamin d concentration; 2026-09-01
  • biomarkers
    bone mineral density; 2026-09-01
  • human trials at or under30
    69
  • Not recorded for this substance
    a recorded half-life
  • smallest human trial
    0; NCT00279461; PHASE2; the smallest recorded human enrolment at or below 30; the registry states no direction of its result; WITHDRAWN

Which of 25 hydroxyvitamin d, 25 hydroxyvitamin d concentration and acr20 did Colecalciferol's trials measure?


25 hydroxyvitamin d, 25 hydroxyvitamin d concentration and acr20 lead 40 outcome terms across Colecalciferol's trials. ClinicalTrials.gov · 2026-09-01

lumbar spine bone mineral density at 12 months, lumbar spine bmd at 24 months, lumbar spine bmd at 36 months, lumbar spine bmd at 60 months, lumbar spine bmd at 120 months and colorectal adenomas follow.

Show the evidence
  • bone mineral density in the lumbar spine
    1
  • bone mineral density by test at 1 and 2 years
    1
  • complete response rate
    1
  • lumbar spine bone mineral density at 12 months
    1
  • lumbar spine bmd at 24 months
    1
  • lumbar spine bmd at 36 months
    1
14 more recorded rows
  • lumbar spine bmd at 60 months
    1
  • lumbar spine bmd at 120 months
    1
  • colorectal adenomas
    1
  • body weight
    1
  • body composition
    1
  • insulin sensitivity
    1
  • muscle strength
    1
  • depression
    1
  • blood pressure
    1
  • acr20
    1
  • vitamin d ria and hplc
    1
  • parathyroid hormone ipth and 3rd generation ria
    1
  • 25 hydroxyvitamin d concentration
    1
  • bone mineral density
    1

recorded 2026-09-01 · last checked 2026-09-04

Which of Colecalciferol's 2 ongoing trials reports first?


2 registered trials of Colecalciferol are open; earliest completion 2026-10. ClinicalTrials.gov · 2026-09-01

Number of Participants With Invasive Cancer of Any Type; Measure the Amount of Bone Mineral Density Loss in Non-metastatic Breast Cancer Patients Receiving a High Dose Vitamin D Therapy Along With a Structured Home-based Walking and…; latest 2026-12-30

Show the evidence

Trial

  • NCT01169259
    "Vitamin D and Omega-3 Trial (VITAL)"; n 25871; "Number of Participants With Invasive Cancer of Any Type"; 2026-10
  • NCT01419730
    "Vitamin D and Physical Activity on Bone Health"; n 191; "Measure the Amount of Bone Mineral Density Loss in Non-metastatic Breast Cancer Patients Receiving a High Dose Vitamin D Therapy Along With a Structured Home-based Walking and Progressive Resistance Exercise Program."; 2026-12-30

recorded 2026-09-01 · last checked 2026-09-04

Which 135 trials of Colecalciferol posted no result?


Posted no result
135 of 135 completed trials
Registrations
NCT00570934, NCT00004488, NCT00004489, NCT00267540, NCT00068276 and NCT00724178, and 129 more
Completion dates
oldest 2002-02; newest 2021-11-22
Show the evidence

Trial

  • NCT00570934
    2002-02
  • NCT00004488
    2002-09
  • NCT00004489
    2002-09
  • NCT00267540
    2003-12
  • NCT00068276
    2006-09
  • NCT00724178
    2006-12
14 further recorded trials
  • NCT00141986
    2007-03
  • NCT00397475
    2007-03
  • NCT00473239
    2007-03
  • NCT00949832
    2007-04
  • NCT00656929
    2007-06
  • NCT00288873
    2007-07
  • NCT00400491
    2007-09
  • NCT00243256
    2007-12
  • NCT00644904
    2008-02
  • NCT00749918
    2008-06
  • NCT00718276
    2008-09
  • NCT01019642
    2008-10
  • NCT00692120
    2008-11
  • NCT00022087
    2009-02

At the median, Colecalciferol's trials enrolled 60 people — anything larger?


Median enrolment
60
Largest enrolment
25871
Registered trials counted
265

What do 23937 spontaneous reports say about Colecalciferol — and not say?


These are reports people sent to a regulator. They do not show the medicine caused the reaction. Nobody counted how many people took the medicine and reported nothing. The same event can be reported more than once, and many reports are incomplete. News coverage, lawsuits and new warnings change how often people report. A count is not a rate and not a risk.

Colecalciferol appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 23937 reaction mentions were counted: pain 3057; alopecia 2627; fatigue 2618; abdominal discomfort 2565. open-targets-adr · CHEMBL1042 · 2026-06-24

Show the evidence
  • pain
    3057
  • alopecia
    2627
  • fatigue
    2618
  • abdominal discomfort
    2565
  • systemic lupus erythematosus
    2532
  • pemphigus
    2530
4 more recorded rows
  • rheumatoid arthritis
    2330
  • glossodynia
    2063
  • swelling
    1906
  • hand deformity
    1709

recorded 2026-06-24 · last checked 2026-09-04

Was Colecalciferol studied with fasting and exercise?


fasting and exercise are named in Colecalciferol's label sentences: "Participants with 25(OH)D concentrations <30 ng/mL and at least one metabolic abnormality, including metabolic syndrome, impaired fasting glucose, dyslipidemia, elevated blood pressure, or increased WC, were randomly assigned to receive placebo, cholecalciferol 14,000 IU/week, or cholecalciferol…" openfda-label+europepmc · 2026-08-21

2 recorded statements; fasting, exercise

Show the evidence
  • fasting
    Participants with 25(OH)D concentrations <30 ng/mL and at least one metabolic abnormality, including metabolic syndrome, impaired fasting glucose, dyslipidemia, elevated blood pressure, or increased WC, were randomly assigned to receive placebo, cholecalciferol 14,000 IU/week, or cholecalciferol 28,000 IU/week for 4 months.
  • exercise
    This parallel-group randomized controlled trial investigated the effects of water-based aerobic exercise training and vitamin D3 supplementation on body mass index (BMI) and physical performance in postmenopausal women who were overweight or obese and had insufficient or deficient levels of serum vitamin D.

recorded 2026-08-21 · last checked 2026-09-04

What is recorded about Colecalciferol and sirtuin?


"Given the neuroprotective properties of Vitamin D3 (VitD3) and resveratrol, this study examined whether their combined administration could modulate Sirt1 and Lingo-1 expression and attenuate neurodegeneration in a 6-hydroxydopamine (6-OHDA) model of PD." — where Colecalciferol and sirtuin appear together. Europe PMC · pathway abstract search · 2026-08-01

sirtuin, mTOR, autophagy, AMPK; PMID 42605571, 40144137, 38259281, 36314337

Show the evidence
  • sirtuin PMID 42605571
    "Given the neuroprotective properties of Vitamin D3 (VitD3) and resveratrol, this study examined whether their combined administration could modulate Sirt1 and Lingo-1 expression and attenuate neurodegeneration in a 6-hydroxydopamine (6-OHDA) model of PD."
  • mTOR PMID 40144137
    "<b>Introduction:</b> This study investigated the effect of vitamin D3 injection combined with high-intensity interval training on cell signaling pathways involved in excessive autophagy, specifically the mTOR (mechanistic target of rapamycin)-Beclin-1-Fyco-1 (FYVE and coiled-coil domain-containing protein 1)-cathepsin D pathway, in the heart tissue of Type 2 diabetes-induced rats. <b>Method:</b>…"
  • autophagy PMID 40144137
    "<b>Introduction:</b> This study investigated the effect of vitamin D3 injection combined with high-intensity interval training on cell signaling pathways involved in excessive autophagy, specifically the mTOR (mechanistic target of rapamycin)-Beclin-1-Fyco-1 (FYVE and coiled-coil domain-containing protein 1)-cathepsin D pathway, in the heart tissue of Type 2 diabetes-induced rats. <b>Method:</b>…"
  • mTOR PMID 40144137
    "HIIT sessions were conducted for 8 weeks, five times per week, at an intensity of 85%-95% of maximum running speed (<i>V</i> <sub>max</sub>), while vitamin D3 was administered weekly via subcutaneous injection at a dose of 10,000 IU/kg. Twenty-four hours after the intervention period, heart and left ventricular tissues were collected for analysis of the levels of autophagy signaling proteins…"
  • autophagy PMID 40144137
    "HIIT sessions were conducted for 8 weeks, five times per week, at an intensity of 85%-95% of maximum running speed (<i>V</i> <sub>max</sub>), while vitamin D3 was administered weekly via subcutaneous injection at a dose of 10,000 IU/kg. Twenty-four hours after the intervention period, heart and left ventricular tissues were collected for analysis of the levels of autophagy signaling proteins…"
  • mTOR PMID 38259281
    "Western blotting was applied to detect p53/AMPK/mTOR signaling, as well as autophagy-, cell cycle-, and apoptosis-related proteins. <b>Results:</b> A total of 485 targets of vitamin D3 activity were obtained and 1200 gastric cancer disease-related targets discovered."
3 more recorded rows
  • AMPK PMID 38259281
    "Western blotting was applied to detect p53/AMPK/mTOR signaling, as well as autophagy-, cell cycle-, and apoptosis-related proteins. <b>Results:</b> A total of 485 targets of vitamin D3 activity were obtained and 1200 gastric cancer disease-related targets discovered."
  • autophagy PMID 38259281
    "Western blotting was applied to detect p53/AMPK/mTOR signaling, as well as autophagy-, cell cycle-, and apoptosis-related proteins. <b>Results:</b> A total of 485 targets of vitamin D3 activity were obtained and 1200 gastric cancer disease-related targets discovered."
  • AMPK PMID 38259281
    "Further, vitamin D3 promoted apoptosis and inhibited the cell cycle in those cell lines, as well as activating the p53/AMPK/mTOR pathway, which promotes autophagy and inhibits tumor development. <b>Conclusion:</b> Our network pharmacological analyses provide preliminarily data supporting a role for vitamin D3 in promoting autophagy and apoptosis in gastric cancer cells, and in activating the…"

sirtuin

  • PMID 36314337
    "Cisplatin treatment in the presence of vitamin D3 inhibited cell invasion and migration and induced apoptosis and enhancing the sirtuin 1 gene abolished the effect of vitamin D3 by regulating mitochondrial reactive oxygen species accumulation and autophagosome formation."
  • PMID 37801071
    "To assess the impact of vitamin D3 (Vit.D) on neurogenesis, we investigated its role in mitigating cognitive impairment and mitochondrial dysfunction through calcium/calmodulin-dependent protein kinase kinase 2 (CAMKK2)-mediated phosphorylation of Sirtuin1 (SIRT1) in an aluminum-chloride-D-galactose (AlCl3-D-gal)-induced AD rat model."
  • AMPK PMID 37801071
    "The hippocampal tissue was used to assess vitamin D3 receptor (VDR) and peroxisome-proliferator-activated-receptor-γ-coactivator-1α (PGC-1α) expression by quantitative real-time polymerase chain reaction (qRT-PCR), CAMKK2, p-SIRT1, phosphorylated-AMP-activated protein kinase (p-AMPK), dynamin-related-protein-1 (Drp1), and mitofusin-1 (Mnf1) proteins by western blot and Ca<sup>2+</sup> levels,…"

recorded 2026-08-01 · last checked 2026-09-04

Where it is registered
Identifiers, relations and other names

The exact record

ChEMBL id
CHEMBL1042
PubChem CID
5283711
CAS number
22350-41-0
RxCUI
2418
InChIKey
QYSXJUFSXHHAJI-YRZJJWOYSA-N
Also called
CHOLECALCIFEROL, 7-dehydrocholesterol, activated, Colecalciferolum, Delsterol, Delta-d, Deparal, Ebivit, Provitina, Ricketon, Vigantoletten
Trade name
Accrete d3, Aciferol d3, Adcal-d3, Biolife vitamin d3, Cacit d3, Calceos, Calcichew d3, Calcichew d3 fte, Calcichew d3 once daily, Calci-d, Cholecalciferol component of dp-r206 vitamin d3, Cholecalciferol component of fosamax plus d
Development code
CHOLECALCIFEROL COMPONENT OF AK R215 COLECALCIFEROL, NSC-375571
Sources (11)

Sources

  • ClinicalTrials.gov clinicaltrials.gov ·
  • ClinicalTrials.gov ClinicalTrials.gov API v2 snapshot 2026-09-01T09:00:05 ·
  • this record's own fields 2,3,5 ·
  • Europe PMC dose-response search ·
  • Europe PMC epigenetic clock search ·
  • Europe PMC pathway abstract search ·
5 more sources

ChEMBL ATC CC BY-SA · ClinicalTrials.gov — US Government work · Europe PMC — metadata only, under the recorded legal gate · Open Targets 26.06 — CC0 · derived from this page's own recorded fields; no external licence · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work

How these records are assembled · Which registers were checked

Index-quality checks
  • identity passed: no open identity hold
  • required summary fields resolved: 5 required field(s) not terminal: Why people use it, Best-supported result, Most important common problem, Biggest unanswered question, Human evidence
  • public claims reviewed: 0 reviewed claim(s); drafts are never rendered
  • source coverage passed: 11 source rows
  • no critical contamination: no quarantine open
  • canonical metadata passed: slug and display name present
  • no raw internal fields: enforced by the copy-contract test over the rendered page

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