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Calcium Carbonate

  • Nutrient
  • 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 Calcium Carbonate does in the body

Heartburn and indigestion, and topping up dietary calcium

In the stomach it is a straightforward acid-base reaction: chalk plus stomach acid gives calcium, water and carbon dioxide, which is why relief is quick and why it can make you belch. In the intestine, a fraction of the freed calcium crosses into the blood, and that requires stomach acid to have dissolved it first — which is why this particular calcium salt is absorbed poorly by people on acid-blocking drugs.

What happened in people

Hip bone density 1.06% higher than placebo after 7.0 years in 36,282 women (P<0.01)

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

That a 1.06% gain in hip bone density is a fracture benefit — in the same trial it was not

Where it acts
The stomach lumen, where it neutralises acid, and the small intestine, where a fraction of the calcium is absorbed
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 · H0G9379FGK · read 2026-08-29

  • The supplement label database classes it as mineral, under the name Calcium.

    NIH Dietary Supplement Label Database · 27 · read 2026-08-29

Where each sentence above came from

No recorded sentence describes the change this makes in a way that stands on its own. The page opens with what it is taken for instead, and the recorded explanation follows below.

Shown as the opening line on this page.

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

The four opening statements run to 99 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
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.
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 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.
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 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
Strength
improvement in muscle strength
Body weight
body weight
Blood sugar
glucose metabolism

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.
Waiting for a reviewer
1 registered performance measure of this kind.
Not recorded
Harms were not a registered measure for this goal.
Only a number moved
1 registered test measure.

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.

Hip fracture

The study did not show it

Who was studied
WHI Calcium/Vitamin D Supplementation Study (NCT00000611)
How many people
36282
Study design
Phase 3, randomised, double-blind, placebo-controlled, average 7.0 years
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
Hazard ratio 0.88 (95% CI 0.72 to 1.08); hip bone density +1.06% (P<0.01); renal calculi hazard ratio 1.17 (1.02 to 1.34)
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. Roughly 46% of participants were already taking personal calcium supplements at randomisation, which a later reanalysis showed obscured a cardiovascular interaction. The on-treatment hazard ratio of 0.71 is widely quoted without noting that it is not a randomised comparison.

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

Form and route. Oral chewable tablet, swallowable tablet, and liquid suspension

Interval reported. 95% CI 0

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

Myocardial infarction and composite cardiovascular events

The study did not show it

Who was studied
Bolland 2010 patient-level and trial-level meta-analysis of calcium supplements
How many people
20072
Study design
Meta-analysis of 15 randomised placebo-controlled trials
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
Patient-level hazard ratio for myocardial infarction 1.31 (95% CI 1.02 to 1.67, P=0.035); trial-level pooled relative risk 1.27 (1.01 to 1.59, P=0.038)
Repeated elsewhere
Partially 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. Cardiovascular outcomes came from self-reports, hospital admissions and death certificates rather than from adjudicated endpoints prespecified in the constituent trials, since none of those trials was designed to measure them.

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

Form and route. Oral chewable tablet, swallowable tablet, and liquid suspension

Interval reported. 95% CI 1

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

What we know
RNAWiki holds 2 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.15 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), Drosophila (fruit fly), Mouse, Rat, Dog, 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

    Calcium Carbonate

    What a person takes: Oral chewable tablet, swallowable tablet, and liquid suspension.

    The measurement behind this step

    Chewed or swallowed. As an antacid it works within minutes because no absorption is needed. As a calcium source it depends on gastric acid to dissolve, so it is taken with food and is a poor choice for anyone on long-term acid suppression.

  2. Getting in

    In the stomach it is simply an acid-base reaction

    Chalk meets stomach acid and neutralises it within minutes. The carbon dioxide produced is why it can make you belch.

    Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.

    The measurement behind this step

    CaCO3 plus two HCl gives CaCl2, H2O and CO2. Onset is a matter of minutes because no absorption is required, and duration is short because the stomach continues to secrete acid. The functional specification for an antacid tablet is acid-neutralising capacity, measured by titration, not a plasma concentration.

  3. Reaching the cell

    The same reaction is what makes the calcium absorbable

    The calcium in chalk is locked up until acid dissolves it. That is why this particular calcium salt works poorly in people taking acid-blocking drugs.

    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

    Dissolution of calcium carbonate requires an acidic environment to liberate ionised calcium. Under proton pump inhibition or after gastric surgery, absorption falls markedly, which is the one clinically actionable difference between this salt and calcium citrate, whose dissolution is acid-independent.

  4. Reaching the cell

    A fraction crosses the intestinal wall

    Only some of the calcium is absorbed, and the proportion falls as the dose rises. Splitting a large dose gets more in than taking it all at once.

    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

    Absorption is transcellular and saturable at low luminal concentrations, mediated by TRPV6 and calbindin under vitamin D control, and paracellular and non-saturable at high concentrations. Fractional absorption therefore falls as dose rises, which is a mass-action property rather than a formulation one.

  5. The change it makes

    Blood calcium rises sharply for a few hours

    A supplement produces a spike in blood calcium that food does not. This difference is the leading explanation for why supplements carry a heart signal that dietary calcium does not.

    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

    A bolus supplement produces a measurable acute rise in serum calcium over several hours, unlike calcium distributed across a meal. The hypothesis linking that excursion to vascular events is unproven, but it is the mechanistic account offered for a difference that is consistent across the observational and randomised literatures.

  6. What that does for a person

    Some is deposited in bone; some appears in urine

    Absorbed calcium either goes into bone or is filtered out by the kidney. More in the urine means more raw material for a stone.

    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

    Calcium not incorporated into hydroxyapatite is excreted renally. In WHI CaD the direct consequence was measured: renal calculi hazard ratio 1.17 (95% CI 1.02 to 1.34), the one clearly significant effect the trial found in either direction.

  7. What that does for a person

    Density rises by about one percent; fractures did not significantly fall

    Seven years of it raised hip bone density by roughly one percent in the largest trial ever run. Hip fractures did not fall significantly, and kidney stones did rise.

    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

    WHI CaD: hip bone density +1.06% (P<0.01); hip fracture hazard ratio 0.88 (95% CI 0.72 to 1.08); total fracture 0.96 (0.91 to 1.02); renal calculi 1.17 (1.02 to 1.34). This is the cleanest illustration in the file of a bone-density gain that did not deliver a fracture reduction.

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

What we know
The record describes 6 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 by test at 1 and 2 years
  • bone mineral density under treatment an anabolic agent
  • lumbar spine bone mineral density at 12 months
  • bone mineral density
  • bone mineral density t from baseline to 12 months
  • blood lead concentration plasma lead concentration
  • serum age levels
  • ambulatory blood pressure
  • lumbar spine bone mineral density at month 24
  • improvement in muscle strength

and 6 more.

Meaningful

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

  • cardiovascular event free survival time

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 (23)
  • mammographic density at 1 year on exemestane
  • time to first skeletal related event
  • 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
  • base study + first extension rate of adverse events
  • second extension number of who experienced an adverse event
  • bone formation rate
  • that experienced an adverse event
  • that discontinued study drug due to an ae
  • that discontinued study treatment due to an ae
  • kidney stones
  • bone neoplasms
  • postoperative parathyroid hormone level
  • predefined tier 1 adverse events
  • all type cancer
  • who experienced an adverse event
  • who discontinued treatment due to an ae

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, for heartburn. And a very large number of postmenopausal women, daily and for years, for bone.

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 largest trial ever run of calcium and vitamin D missed hip fracture, clinical spine fracture and total fracture
  • Kidney stones rose significantly, and the USPSTF later graded that harm as adequately evidenced
  • The cardiovascular signal was invisible in WHI itself because 46% of participants were already taking their own calcium at randomisation
  • Milk-alkali syndrome, thought to have been abolished by acid-suppressing drugs, returned as calcium-alkali syndrome driven by supplements
  • 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.

Something else had to happen too

In the studies it was paired with training, a diet or another treatment.

On this record: A supplement produces a spike in blood calcium that food does not. This difference is the leading explanation for why supplements carry a heart signal that dietary calcium does not.

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.

Other reasons RNAWiki checked and found nothing for (9)
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. 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.
The product may not be what it says
Contents of a sold product are not always what the label states. 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 chewable tablet, swallowable tablet, and liquid suspension

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

Chewed or swallowed. As an antacid it works within minutes because no absorption is needed. As a calcium source it depends on gastric acid to dissolve, so it is taken with food and is a poor choice for anyone on long-term acid suppression.

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 and what that means for what is in the pack.

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

Sold over the counter without a boxed warning. The label limits antacid use to the stated maximum in 24 hours and to two weeks without medical supervision, and warns of interactions with prescription drugs. Constipation and bloating are the common effects. The measured harms in the randomised literature are kidney stones, hazard ratio 1.17 (95% CI 1.02 to 1.34) in WHI, and a contested increase in myocardial infarction, relative risk 1.24 (1.07 to 1.45) in pooled trials. High-dose use with alkali can produce calcium-alkali syndrome: hypercalcaemia, metabolic alkalosis and renal insufficiency. It binds thyroid hormone, tetracyclines, quinolones, iron and bisphosphonates in the gut.

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.

Calcium Carbonate appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 23386 reaction mentions were counted. One report can name several reactions.

The recorded terms (10)
  • pain — 2918 reaction mentions
  • alopecia — 2566 reaction mentions
  • abdominal discomfort — 2535 reaction mentions
  • pemphigus — 2523 reaction mentions
  • systemic lupus erythematosus — 2523 reaction mentions
  • fatigue — 2384 reaction mentions
  • rheumatoid arthritis — 2312 reaction mentions
  • glossodynia — 2063 reaction mentions
  • swelling — 1859 reaction mentions
  • hand deformity — 1703 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 unclearRead from sources, not yet reviewed

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 chewable tablet, swallowable tablet, and liquid suspension

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

As an antacid it works within minutes because no absorption is needed. As a calcium source it depends on gastric acid to dissolve, so it is taken with food and is a poor choice for anyone on long-term acid suppression.

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.

What is recorded as being sold

  • 1095 products list this as an active ingredient in the United States drug directory. 640 of them contain it and nothing else.

    FDA National Drug Code directory · 71971-6036 · read 2026-08-29

  • They are sold as bar, chewable, capsule, capsule, gelatin coated, gel, granule and gum, chewing, taken auricular (otic), dental, nasal and oral.

    FDA National Drug Code directory · 71971-6036 · read 2026-08-29

  • The regulator's established pharmacologic class for it is blood coagulation factor [epc], calcium [cs] and cations.

    FDA National Drug Code directory · 71971-6036 · read 2026-08-29

  • 983 published labels name it as an active ingredient. 544 of them describe this substance alone, which is where its own label text on this page comes from.

    US prescribing information · 899f057a-914d-49ca-a9fd-9fc48149782a · read 2026-08-29

  • Those labels are classed as human otc drug and human prescription drug.

    US prescribing information · 899f057a-914d-49ca-a9fd-9fc48149782a · read 2026-08-29

  • 16381 marketed supplement labels list this ingredient, classed as mineral, other combinations and single vitamin and mineral.

    NIH Dietary Supplement Label Database · 221401 · read 2026-08-29

  • Those labels carry all other, nutrient and structure/function claims. A claim of that kind is written by the manufacturer and is not assessed by any regulator, so its presence says nothing about whether it is true.

    NIH Dietary Supplement Label Database · 221401 · read 2026-08-29

  • Recorded price in US: 0.00812 USD per one unit as the pricing file counts it — a tablet, capsule, patch or single item, for the one priced product, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..

    Recorded source · 2026-08-26 · read 2026-08-28

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 by test at 1 and 2 years; bone mineral density under treatment an anabolic agent; 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.

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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 a 1.06% gain in hip bone density is a fracture benefit — in the same trial it was not

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 calcium supplements substitute for the drugs elsewhere in this file, when those trials gave calcium to their placebo arms too

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 an essential nutrient is harmless as a supplement, when the randomised pooled estimate for myocardial infarction is above 1

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 on-treatment hip fracture hazard ratio of 0.71 in WHI is the trial’s result — it is an adherence-censored analysis, not the randomised comparison

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 Calcium Carbonate 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.

In 36,282 women over seven years, hip fracture was not significantly reduced
In plain words
The largest trial ever run of calcium and vitamin D gave it to more than thirty-six thousand postmenopausal women for seven years. Hip bone density rose by about one percent. Hip fractures did not fall significantly. Kidney stones went up.
What was measured
Hip fracture hazard ratio 0.88 (95% CI 0.72 to 1.08); renal calculi hazard ratio 1.17 (1.02 to 1.34)
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The Women’s Health Initiative Calcium/Vitamin D trial randomised 36,282 postmenopausal women aged 50 to 79 to 1000 mg of elemental calcium as calcium carbonate with 400 IU of vitamin D3 daily or placebo, with fractures ascertained over an average of 7.0 years. Hip bone density was 1.06% higher on treatment (P<0.01). In intention-to-treat analysis the hazard ratio was 0.88 for hip fracture (95% CI 0.72 to 1.08), 0.90 for clinical spine fracture (0.74 to 1.10) and 0.96 for total fractures (0.91 to 1.02) — none significant. Renal calculi increased, hazard ratio 1.17 (95% CI 1.02 to 1.34). Censoring at non-adherence lowered the hip fracture hazard ratio to 0.71 (0.52 to 0.97), which is an on-treatment analysis rather than a randomised comparison. Effects did not vary by prerandomisation serum vitamin D.
Source
Jackson RD et al., N Engl J Med 2006;354:669-683 (WHI CaD, NCT00000611)
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
The cardiovascular signal that changed how supplements are viewed
In plain words
Pooling the randomised trials, people taking calcium supplements had more heart attacks than people taking placebo. The largest trial had missed it because nearly half its participants were already taking calcium of their own before they were randomised.
What was measured
That a supplement of an essential nutrient must be at worst harmless — the pooled randomised evidence puts myocardial infarction at a relative risk of 1.24 (95% CI 1.07 to 1.45)
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Bolland and colleagues pooled 15 randomised placebo-controlled trials of calcium supplements of at least 500 mg per day without co-administered vitamin D. In the five with patient-level data (8151 participants, median follow-up 3.6 years), 143 allocated to calcium had a myocardial infarction against 111 on placebo, hazard ratio 1.31 (95% CI 1.02 to 1.67, P=0.035); stroke 1.20 (0.96 to 1.50) and death 1.09 (0.96 to 1.23) were not significant. Trial-level data in 11,921 participants gave a pooled relative risk of 1.27 (1.01 to 1.59, P=0.038). The following year the same group reanalysed the WHI limited-access dataset and found an interaction with personal calcium supplement use at randomisation: in the 16,718 women (46%) not already taking supplements, hazard ratios for cardiovascular events ran 1.13 to 1.22, while in women already taking them risk did not change with allocation. Meta-analysis across eight trials plus the WHI non-users, 28,072 participants and 1384 events, gave a relative risk of 1.24 (1.07 to 1.45, P=0.004) for myocardial infarction and 1.15 (1.03 to 1.27, P=0.009) for myocardial infarction or stroke. The authors of both papers called for a reassessment of the role of calcium supplements in osteoporosis management. The finding has been disputed, and the disclosure statement records the senior author’s research support from a dairy company.
Source
Bolland MJ et al., BMJ 2010;341:c3691; Bolland MJ et al., BMJ 2011;342:d2040
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
The USPSTF recommends against it for fracture prevention in healthy postmenopausal women
In plain words
The United States preventive task force looked at the evidence and issued its second-strongest negative grade: do not take 1000 mg of calcium with 400 IU of vitamin D to prevent fractures if you are a healthy postmenopausal woman living at home.
What was measured
D recommendation against ≤400 IU vitamin D with ≤1000 mg calcium for primary fracture prevention in community-dwelling postmenopausal women
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The 2018 USPSTF statement found adequate evidence that daily supplementation with 400 IU or less of vitamin D and 1000 mg or less of calcium has no benefit for the primary prevention of fractures in community-dwelling postmenopausal women, and issued a D recommendation against it. It found inadequate evidence to estimate benefits at higher doses, or in men and premenopausal women at any dose, issuing I statements for both. It found adequate evidence that supplementation with vitamin D and calcium increases the incidence of kidney stones. The recommendations explicitly exclude people with osteoporosis, vitamin D deficiency, a previous fracture, or long-term steroid use — which is most of the population the drugs elsewhere in this file are for.
Source
US Preventive Services Task Force. JAMA 2018;319:1592-1599
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
It is the invisible floor under every other page in this file
In plain words
Almost every osteoporosis drug trial gave calcium and vitamin D to both groups, including the placebo group. So the benefits reported on those pages are benefits on top of calcium, not instead of it.
What was measured
Calcium and vitamin D supplied to both arms in the pivotal trials of alendronate, risedronate, raloxifene and zoledronic acid
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
In the Fracture Intervention Trial, all participants reporting calcium intake of 1000 mg per day or less received a supplement containing 500 mg of calcium and 250 IU of cholecalciferol. In VERT-NA all subjects received 1000 mg of calcium daily with up to 500 IU of vitamin D where baseline levels were low. In MORE all women received supplemental calcium and cholecalciferol. In HORIZON-RFT all patients received supplemental vitamin D and calcium. This is the reason the drug effects elsewhere in this file are increments rather than totals, and it is also why calcium cannot be presented as an alternative to those drugs: it was present in both arms of the trials that established them.
Source
Cummings SR et al., JAMA 1998;280:2077-2082; Harris ST et al., JAMA 1999;282:1344-1352; Ettinger B et al., JAMA 1999;282:637-645; Lyles KW et al., N Engl J Med 2007;357:1799-1809
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
Taken with an alkali at high dose it can cause a named syndrome
In plain words
Large amounts of calcium taken with something alkaline — which chalk itself is — can produce a triad of high blood calcium, alkaline blood and failing kidneys. It used to come from milk and bicarbonate for ulcers; now it comes from supplements.
What was measured
The defining triad: hypercalcaemia, metabolic alkalosis and renal insufficiency after combined calcium and alkali ingestion
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Ingestion of calcium with alkali produces hypercalcaemia, metabolic alkalosis and renal insufficiency. Originally described as milk-alkali syndrome in patients treating peptic ulcer with milk and bicarbonate, the condition largely disappeared with the arrival of acid-suppressing drugs and returned as calcium-alkali syndrome, driven by calcium carbonate taken for bone or for heartburn. The reviewers describe it as an important cause of morbidity that may be rising, and as an unintended consequence of shifts in calcium and vitamin D intake in segments of the population. Calcium carbonate supplies both halves of the syndrome at once, which is why it is the salt most often implicated.
Source
Patel AM, Adeseun GA, Goldfarb S. Nutrients 2013;5:4880-4893
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

FDA substance identifier (UNII)
H0G9379FGK
RxNorm concept
308892

Checks this page had to pass

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    Trial roles classified for highlighted evidence

    No registered study is classified as testing this substance.

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    Safety mode resolved

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

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What is missing or unclearRead from sources, not yet reviewed

How this medicine reached us

Kept near the foot of the page. A historical event moves up only when it changes something about this substance today.

What the approval register records

  • 6 approved applications cover products containing this substance. The earliest was NDA018519, approved 19820622 to BAXTER HLTHCARE.

    Drugs@FDA application register · NDA018519 · read 2026-08-29

  • Marketing status on the register: discontinued and over-the-counter.

    Drugs@FDA application register · NDA018519 · read 2026-08-29

  • The earliest marketing start date recorded for a listed product is 19830303.

    FDA National Drug Code directory · 71971-6036 · read 2026-08-29

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What to learn next

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

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What is not here

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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.

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Chalk, which neutralises stomach acid in minutes and supplies the mineral bone is built from — and which, given with 400 IU of vitamin D to 36,282 postmenopausal women for seven years, raised hip bone density by 1.06% while missing hip fracture at a hazard ratio of 0.88 (95% CI 0.72 to 1.08) and significantly increasing kidney stones at 1.17 (1.02 to 1.34).

Recorded evidence blocks (13)

What did Calcium Carbonate's largest trial (16071 people) and its longest (12 years) measure?


16071 people in Calcium Carbonate's largest registered study, 12 years in its longest registered window, measuring Rate of Biological Aging. ClinicalTrials.gov · 2026-09-01

84 na, 42 phase2, 32 phase3, 23 phase4, 17 phase1, 4 early phase1; NCT00153816; 2016-06. Last human test completed 2026, NCT07570043.

Interpretation These counts include studies where Calcium Carbonate 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
    84
  • phase2
    42
  • phase3
    32
  • phase4
    23
  • phase1
    17
  • early phase1
    4
1 more recorded row
  • Last recorded human test NCT07570043
    2026-05-27

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

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


C. elegans: lifespan, Drosophila: lifespan, NHP: biomarker, mouse: lifespan, rat: lifespan, dog: lifespan and human: mechanism-only (196): the rungs where Calcium Carbonate has a recorded finding. Europe PMC and ClinicalTrials.gov · organism ladder · 2026-09-01

Interpretation Rate of Biological Aging — the recorded outcome words.

Yeast C. elegans lifespanDrosophila lifespanMouse lifespanRat lifespanDog lifespanNon-human primate biomarkerHuman mechanism-only
Show the evidence
  • C. elegans
    lifespan
  • Drosophila
    lifespan
  • NHP
    biomarker
  • mouse
    lifespan
  • rat
    lifespan
  • dog
    lifespan
1 more recorded row
  • human NCT05302713
    mechanism-only; Rate of Biological Aging; 196

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

8 of Calcium Carbonate's trials stopped: safety, accrual/recruitment, other?


safety (1), accrual/recruitment (4) and other (3): Calcium Carbonate's stop wording, clustered. ClinicalTrials.gov · 2026-09-01

"Withdrawn due to poor accrual/lack of funding"; 8 of 196 registered studies

Show the evidence

Trial

  • NCT00470353
    terminated; "Withdrawn due to poor accrual/lack of funding"
  • NCT00650637
    terminated; "The study was prematurely discontinued due to administrative reasons on August 18, 2003. There were no safety concerns that led to the decision to terminate."
  • NCT00837655
    withdrawn; "PI retired"
  • NCT02282384
    withdrawn; "Sites were unable to recruit participants"
  • NCT03113994
    terminated; "COVID-19 Pandemic"
  • NCT03612466
    withdrawn; "Study withdrawn before any participants could be enrolled. Issues being able to effectively recruit participants into the study."
2 further recorded trials
  • NCT03751813
    terminated; "IRB had concerns about study; terminated"
  • NCT05302713
    withdrawn; "No participants were enrolled"

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

Human studies of Calcium Carbonate used Calcium Supplement 500 mg — over how long?


Human studies of Calcium Carbonate used "Calcium Supplement 500 mg". ClinicalTrials.gov · 2026-09-01

6 recorded entries; human; also "Calcium Carbonate 1200 mg", "1500 mg Calcium and 1200 IU Vitamin D for 2 months", "Calcium Carbonate 500 MG"

Show the evidence

human

  • NCT00692913
    Calcium Supplement 500 mg
  • NCT01762995
    Calcium Carbonate 1200 mg
  • NCT02706158
    1500 mg Calcium and 1200 IU Vitamin D for 2 months
  • NCT04479566
    Calcium Carbonate 500 MG
  • NCT05577507
    Calcium Carbonate 500 MG Oral Tablet
  • NCT07763509
    500 mg calcium from milk-derived minerals

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

Could one person measure Calcium Carbonate's effect on bone mineral density by test at 1 and 2 years?


Bone mineral density by test at 1 and 2 years: measured in Calcium Carbonate's trials.

bone mineral density by test at 1 and 2 years is the recorded endpoint.

Show the evidence

biomarkers

  • bone mineral density by test at 1 and 2 years; 2026-09-01
  • mammographic density at 1 year on exemestane; 2026-09-01
  • bone mineral density under treatment an anabolic agent; 2026-09-01
  • time to first skeletal related event; 2026-09-01
  • lumbar spine bone mineral density at 12 months; 2026-09-01
  • lumbar spine bmd at 24 months; 2026-09-01
14 more recorded rows
  • biomarkers
    lumbar spine bmd at 36 months; 2026-09-01
  • 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
    bone mineral density; 2026-09-01
  • biomarkers
    bone mineral density t from baseline to 12 months; 2026-09-01
  • biomarkers
    base study + first extension rate of adverse events; 2026-09-01
  • biomarkers
    second extension number of who experienced an adverse event; 2026-09-01
  • biomarkers
    blood lead concentration plasma lead concentration; 2026-09-01
  • biomarkers
    bone formation rate; 2026-09-01
  • biomarkers
    that experienced an adverse event; 2026-09-01
  • biomarkers
    that discontinued study drug due to an ae; 2026-09-01
  • biomarkers
    that discontinued study treatment due to an ae; 2026-09-01
  • biomarkers
    kidney stones; 2026-09-01
  • human trials at or under30
    53
  • Not recorded for this substance
    a recorded half-life
  • smallest human trial
    0; NCT00837655; NA; the smallest recorded human enrolment at or below 30; the registry states no direction of its result; WITHDRAWN

Which of all type cancer, ambulatory blood pressure and base study + first extension rate of adverse events did Calcium Carbonate's trials measure?


all type cancer, ambulatory blood pressure and base study + first extension rate of adverse events lead 40 outcome terms across Calcium Carbonate's trials. ClinicalTrials.gov · 2026-09-01

time to first skeletal related event, 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 and lumbar spine bmd at 120 months follow.

Show the evidence
  • bone mineral density by test at 1 and 2 years
    1
  • mammographic density at 1 year on exemestane
    1
  • bone mineral density under treatment an anabolic agent
    1
  • time to first skeletal related event
    1
  • lumbar spine bone mineral density at 12 months
    1
  • lumbar spine bmd at 24 months
    1
14 more recorded rows
  • lumbar spine bmd at 36 months
    1
  • lumbar spine bmd at 60 months
    1
  • lumbar spine bmd at 120 months
    1
  • colorectal adenomas
    1
  • bone mineral density
    1
  • bone mineral density t from baseline to 12 months
    1
  • base study + first extension rate of adverse events
    1
  • second extension number of who experienced an adverse event
    1
  • blood lead concentration plasma lead concentration
    1
  • bone formation rate
    1
  • that experienced an adverse event
    1
  • that discontinued study drug due to an ae
    1
  • that discontinued study treatment due to an ae
    1
  • kidney stones
    1

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

Which of Calcium Carbonate's 23 ongoing trials reports first?


23 registered trials of Calcium Carbonate are open; earliest completion 2025-02-07. ClinicalTrials.gov · 2026-09-01

Percent change from baseline in areal bone mineral density (via DXA) of the lumbar spine, total hip, and femoral neck; Effects of treatment with TPTD+cinacalcet compared to TPTD+PBO on lumbar spine BMD in men with low bone mass; latest 2029-12

Show the evidence

Trial

  • NCT02822378
    "Dried Plums and Bone Health in Postmenopausal Women"; n 322; "Percent change from baseline in areal bone mineral density (via DXA) of the lumbar spine, total hip, and femoral neck"; 2027-12-31
  • NCT03994172
    "Novel Combination Therapy for Osteoporosis in Men"; n 40; "Effects of treatment with TPTD+cinacalcet compared to TPTD+PBO on lumbar spine BMD in men with low bone mass"; 2026-06-30
  • NCT05115760
    "Pea Protein Oral Nutrition Supplement for the Reduction of Gastrostomy Tube Placement Rate in Patients With Locally Advanced Head and Neck Cancer Undergoing Chemoradiation Therapy"; n 57; "Compliance rate"; 2028-06-01
  • NCT05571514
    "Study of the Impact of Mother-of-pearl Nutritional Supplementation on the Prevention of Post-menopausal Osteoporosis"; n 200; "Change in bone loss at lumbar site"; 2028-11
  • NCT05976035
    "Exercise vs. Supplements in Rotator Cuff-Related Shoulder Pain"; n 58; "Visual Analog Scale (VAS)"; 2026-12-01
  • NCT06214598
    "Anti-Inflammatory Diet in BRC Patients on Aromatase Inhibitors"; n 90; "Nutritional status"; 2026-11-30
14 further recorded trials
  • NCT06241183
    "Famotidine and Antacids for Treatment of Dyspepsia"; n 80; "Verbal Numerical Pain Score"; 2027-12-31
  • NCT06352775
    "Calcium Carbonate on Labor Induction"; n 250; "Duration of induction time"; 2026-12-30
  • NCT06467825
    "Effect of Sex on Orthostatic Intolerance and Cardiovascular Response During Lunar Descent and Ascent"; n 38; "Plasma Volume"; 2025-09
  • NCT06503978
    "Microbiota Transplant Therapy for Children With Both Autism Spectrum Disorder and Gastrointestinal Disorders"; n 60; "Childhood Autism Rating Scale (CARS-2)"; 2026-08-17
  • NCT06580782
    "Calcium Carbonate to Augment Labor Contractions"; n 60; "Number of Participants Consented"; 2025-12
  • NCT06660524
    "Calcium-Phosphorus Regulation Therapy on Heart Valve Disease"; n 196; "The change of valve calcification score on CT scan from baseline to 1 year of treatment."; 2025-12
  • NCT06722898
    "Rapid BAC Reduction with Nutraceutical Blend Study"; n 35; "Blood Alcohol Concentration"; 2025-02-07
  • NCT06763536
    "Oral Nicotine Pouches Versus Nicotine Replacement Therapy to Reduce Cigarette Use for Smokers in Rural Appalachia"; n 1000; "Biochemically verified 7-day point prevalence abstinence from cigarettes"; 2028-12-31
  • NCT06841458
    "Six-Month Single-Blind, Placebo-Controlled Study of a Dietary Supplement Supplement on Hair Growth in 45 Volunteers"; n 45; "Objective Evaluation of Hair Health Benefits After Six Months of Treatment"; 2025-06-01
  • NCT07024940
    "Short-term Effects of Caffeine and a Multi-ingredient Pre-workout on Exercise Performance"; n 12; "Change in anaerobic power measured by a 30-second all-out effort on a cycle ergometer"; 2026-09-01
  • NCT07117110
    "Lycopene as a Dietary Compliance Biomarker"; n 10; "To measure lycopene concentration after a single dose of dietary lycopene."; 2025-12-31
  • NCT07120997
    "Prunes Preventing Bone Loss in Perimenopause"; n 124; "Percent change from baseline in areal bone mineral density (via DXA) of the lumbar spine, total hip, and femoral neck"; 2029-12
  • NCT07213063
    "Effects of Chronic Creatine and Beta-Hydroxy-Beta-Methylbutyrate Supplementation on Oxidative Stress, Inflammation, Muscle Strength, and Body Composition in Individuals With Down Syndrome"; n 50; "Lean mass"; 2026-05-30
  • NCT07242365
    "Soylent in Reducing Gastrostomy Tube Rates in Patients With Locally Advanced Head and Neck Cancer Undergoing Chemoradiotherapy"; n 60; "Compliance with Soylent nutritional supplementation"; 2027-12-31

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

Which running trial of Calcium Carbonate could settle function?


NCT07602426 measures Change From Baseline to Week 4 in PROMIS Physical Function T-score, reading out 2026-05-31.

1 open trial; n 40; "A Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Effects of resO™ Bone and Joint Support Postbiotic on Physical Function, Pain Interference, and Mobility in Adults With Joint…"

Show the evidence
  • Trial NCT07602426
    "A Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Effects of resO™ Bone and Joint Support Postbiotic on Physical Function, Pain Interference, and Mobility in Adults With Joint Discomfort"; n 40; "Change From Baseline to Week 4 in PROMIS Physical Function T-score"; 2026-05-31

Which 90 trials of Calcium Carbonate posted no result?


Posted no result
90 of 90 completed trials
Registrations
NCT00670501, NCT00000426, NCT00000429, NCT01723007, NCT00686192 and NCT00004488, and 84 more
Completion dates
oldest 1999-04; newest 2024-05-27
Show the evidence

Trial

  • NCT00670501
    1999-04
  • NCT00000426
    2000-06
  • NCT00000429
    2001-05
  • NCT01723007
    2001-06
  • NCT00686192
    2002-07
  • NCT00004488
    2002-09
14 further recorded trials
  • NCT00004489
    2002-09
  • NCT00302627
    2002-11
  • NCT00000415
    2003-03
  • NCT00558623
    2005-04
  • NCT03813329
    2005-12-31
  • NCT03878667
    2005-12-31
  • NCT00630214
    2006-02
  • NCT01514851
    2006-05
  • NCT00061256
    2006-09
  • NCT00560300
    2006-11
  • NCT03286673
    2007-03
  • NCT00461448
    2007-04
  • NCT00030238
    2007-12-14
  • NCT00054418
    2008-05

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


Median enrolment
60
Largest enrolment
16071
Registered trials counted
196

What do 23386 spontaneous reports say about Calcium Carbonate — 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.

Calcium Carbonate appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 23386 reaction mentions were counted: pain 2918; alopecia 2566; abdominal discomfort 2535; pemphigus 2523. open-targets-adr · CHEMBL1200539 · 2026-06-24

Show the evidence
  • pain
    2918
  • alopecia
    2566
  • abdominal discomfort
    2535
  • pemphigus
    2523
  • systemic lupus erythematosus
    2523
  • fatigue
    2384
4 more recorded rows
  • rheumatoid arthritis
    2312
  • glossodynia
    2063
  • swelling
    1859
  • hand deformity
    1703

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

Was Calcium Carbonate studied with exercise?


exercise is named in Calcium Carbonate's label sentences: "Using a randomized crossover design, 20 participants (age: 36±5years; BMI: 38.7±7.6kg/m2) completed high-intensity interval exercise (HIIE; 10x1-min cycling intervals at ≥90%HRmax) followed by consumption of GY (247kcal, 14g carbohydrate, 32g protein, 350mg calcium) or isoenergetic CP (247kcal, 62g…" openfda-label+europepmc · 2026-08-06

1 recorded statement; exercise

Show the evidence
  • exercise
    Using a randomized crossover design, 20 participants (age: 36±5years; BMI: 38.7±7.6kg/m2) completed high-intensity interval exercise (HIIE; 10x1-min cycling intervals at ≥90%HRmax) followed by consumption of GY (247kcal, 14g carbohydrate, 32g protein, 350mg calcium) or isoenergetic CP (247kcal, 62g carbohydrate, 0g protein, 0mg calcium).

recorded 2026-08-06 · last checked 2026-09-04

What is recorded about Calcium Carbonate and mTOR?


"In this study, we demonstrate for the first time that <i>miR-17-5p</i> inhibits CSFV replication through an autophagy-dependent mechanism by targeting polycystin-2 (<i>PKD2</i>), a key calcium channel protein that regulates the AMPK/mTOR signaling pathway." — where Calcium Carbonate and mTOR appear together. Europe PMC · pathway abstract search · 2026-06-11

mTOR, AMPK, autophagy, NAD+, sirtuin, IGF-1; PMID 41656913, 40905115, 42353025, 39636756

Show the evidence
  • mTOR PMID 41656913
    "In this study, we demonstrate for the first time that <i>miR-17-5p</i> inhibits CSFV replication through an autophagy-dependent mechanism by targeting polycystin-2 (<i>PKD2</i>), a key calcium channel protein that regulates the AMPK/mTOR signaling pathway."
  • AMPK PMID 41656913
    "In this study, we demonstrate for the first time that <i>miR-17-5p</i> inhibits CSFV replication through an autophagy-dependent mechanism by targeting polycystin-2 (<i>PKD2</i>), a key calcium channel protein that regulates the AMPK/mTOR signaling pathway."
  • autophagy PMID 41656913
    "In this study, we demonstrate for the first time that <i>miR-17-5p</i> inhibits CSFV replication through an autophagy-dependent mechanism by targeting polycystin-2 (<i>PKD2</i>), a key calcium channel protein that regulates the AMPK/mTOR signaling pathway."
  • mTOR PMID 41656913
    "Mechanistically, <i>PKD2</i> regulates intracellular calcium dynamics, modulating the AMPK/mTOR-autophagy axis to promote CSFV proliferation."
  • AMPK PMID 41656913
    "Mechanistically, <i>PKD2</i> regulates intracellular calcium dynamics, modulating the AMPK/mTOR-autophagy axis to promote CSFV proliferation."

autophagy

  • PMID 41656913
    "Mechanistically, <i>PKD2</i> regulates intracellular calcium dynamics, modulating the AMPK/mTOR-autophagy axis to promote CSFV proliferation."
  • PMID 41656913
    "This work uncovers a novel host antiviral mechanism in which a miRNA controls virus-induced autophagy via calcium signaling."
  • NAD+ PMID 40905115
    "Alizarin red staining and calcium content assay revealed that pharmacological inhibition or knockdown of NAMPT exacerbated vascular smooth muscle cell calcification, whereas overexpression of NAMPT reduced mineral deposition under osteogenic conditions."
  • mTOR
    "Fluctuating energetic states reconfigure AMP‑activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), calcium/calmodulin‑dependent protein kinase II (CaMKII) and sirtuin‑1 (SIRT1) signaling, influencing DNA methylation, histone acetylation, and microRNA programs governed by peroxisome proliferator‑activated receptor‑γ coactivator‑1α (PGC‑1α) and brain‑derived neurotrophic factor…"
  • AMPK
    "Fluctuating energetic states reconfigure AMP‑activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), calcium/calmodulin‑dependent protein kinase II (CaMKII) and sirtuin‑1 (SIRT1) signaling, influencing DNA methylation, histone acetylation, and microRNA programs governed by peroxisome proliferator‑activated receptor‑γ coactivator‑1α (PGC‑1α) and brain‑derived neurotrophic factor…"

sirtuin

  • "Fluctuating energetic states reconfigure AMP‑activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), calcium/calmodulin‑dependent protein kinase II (CaMKII) and sirtuin‑1 (SIRT1) signaling, influencing DNA methylation, histone acetylation, and microRNA programs governed by peroxisome proliferator‑activated receptor‑γ coactivator‑1α (PGC‑1α) and brain‑derived neurotrophic factor…"
  • PMID 42353025
    "Mechanistically, SC regulated multiple signaling pathways, including mitogen-activated protein kinase (MAPK), toll-like receptor 4/nuclear factor kappa B (TLR4/ NF-κB), PI3K/AKT, nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1), and the calcium/calmodulin-dependent protein kinase kinase-AMP-activated protein kinase-sirtuin 1 (CaMKK-AMPK-Sirt1) axis."
  • PMID 39636756
    "Overall, SIRT1 plays a protective role in diabetic cardiomyopathy by reducing apoptosis, regulating autophagy and mitophagy, and modulating calcium channel activity."
  • IGF-1
    "In neocortical neurons, by contrast, IGF-1 consistently reduced glutamate- and AMPA-evoked calcium peaks, suggesting an inhibitory effect on AMPA receptors."

recorded 2026-06-11 · last checked 2026-09-04

Where it is registered
Identifiers, relations and other names

The exact record

ChEMBL id
CHEMBL1200539
PubChem CID
10112
CAS number
471-34-1
RxCUI
1897
InChIKey
VTYYLEPIZMXCLO-UHFFFAOYSA-L
Trade name
Adcal, Albacar, Cacit, Calc 500, Calcette, Calcichew, Calcichew fte, Calcidrink, Citrical, Os-cal, Purecal, Remegel
Also called
Calcii carbonas, Calcite, Calcitum, Chalk, Ci 77220, E170, Glauberitum, Han shui shi, Hydrolyzed pearl, Limestone, Limestone, ground, Marble dust
Salt form
Calcium (as calcium carbonate), Calcium carbonate component of pepcid complete, Precpitated calcium carbonate, calcium supplement, Calcium Antacid
Development code
E-170(I), INS-170(I), INS NO.170(I), NDI 443
Sources (10)

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 pathway abstract search ·
  • Europe PMC search ·
4 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: 10 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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