This page shows what was measured, who it was measured in, and what that does not settle.
What Finasteride does in the body
Finasteride blocks that enzyme, so the local supply of the growth signal falls by roughly seventy per cent and the gland slowly shrinks.
The prostate grows under the influence of a hormone called dihydrotestosterone, which the gland makes from testosterone using a specific enzyme. Because this is a change in tissue rather than in muscle tone, nothing happens for months — and because the gland is genuinely smaller afterwards, the benefit is a different kind from the one an alpha-blocker gives. The same enzyme operates in hair follicles and in sexual tissue, which is why the drug also grows hair and why its adverse effects are sexual.
Why people take it. An enlarged prostate causing a weak stream and frequent urination, where the aim is to shrink the gland rather than relax it
What happened in people
15-year survival 78.0% against 78.2%, hazard ratio for death 1.02 (95% CI 0.97 to 1.08, P=0.46), with up to 18 years of follow-up
✎ 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.
MTOPS — Medical Therapy of Prostatic Symptoms (NCT00021814) · a recorded source, not a stored snapshot
The limit that matters most
Seven cents a tablet at United States pharmacy acquisition cost across fifty listed products — among the cheapest drugs in this file and the only one that halves an operation rate
Where it acts
Prostatic epithelial and stromal cells, where type II 5-alpha-reductase converts testosterone to dihydrotestosterone
Kind of result
Living longer, or avoiding a major event
Supervision
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
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 158 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 people◇Read 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 32 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.
Goal
Life outcome
What a body can do
How a person feels
A test result
A step in the body
Harms
How long
Who was studied
Strength
∅Nothing 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.
Fertility and sexual health
∅Nothing 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 sugar
∅Nothing 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.
Body weight
∅Nothing 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
1 repetition maximum strength testing
Fertility and sexual health
maximum testosterone concentration
Blood sugar
insulin sensitivity
Body weight
total body fat
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 people◇Read 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.
Incidence of acute urinary retention and of the need for BPH-related surgery over four years
✓ The study showed what it set out to show
Who was studied
PLESS — Finasteride Long-Term Efficacy and Safety Study
How many people
3040
Study design
Phase 3 randomised double-blind placebo-controlled, 4 years
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
Surgery 69/1513 (5%) on finasteride against 152/1503 (10%) on placebo, 55% risk reduction (95% CI 41 to 65). Acute urinary retention 42 (3%) against 99 (7%), 57% reduction (95% CI 40 to 69). Symptom score -3.3 against -1.3, P<0.001
Repeated elsewhere
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. Complete outcome data were available for 2,760 of the 3,040 randomised. Year-one sexual adverse effects were roughly double placebo: impotence 8.1% against 3.7%, decreased libido 6.4% against 3.4%.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral tablet, once daily; 5 mg for benign prostatic hyperplasia and 1 mg for androgenetic alopecia
Interval reported. 95% CI 41 to 65)
Written into the record, not signed off as a reviewed claim.
Overall clinical progression: a 4-point rise in AUA symptom score, acute urinary retention, incontinence, renal insufficiency or recurrent urinary tract infection
✓ The study showed what it set out to show
Who was studied
MTOPS — Medical Therapy of Prostatic Symptoms (NCT00021814)
How many people
3047
Study design
Randomised double-blind placebo-controlled four-arm, mean 4.5 years
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
Risk reduction against placebo: doxazosin 39% (P<0.001), finasteride 34% (P=0.002), combination 66% (P<0.001, and superior to each monotherapy at P<0.001). Acute urinary retention and invasive therapy reduced by finasteride and combination (both P<0.001) but not by doxazosin
Repeated elsewhere
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. The composite primary endpoint is dominated by the 4-point symptom-score threshold, which is why doxazosin and finasteride look comparable on it while diverging completely on catheters and operations.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral tablet, once daily; 5 mg for benign prostatic hyperplasia and 1 mg for androgenetic alopecia
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Prevalence of prostate cancer over the seven years of the study
✓ The study showed what it set out to show
Who was studied
PCPT — Prostate Cancer Prevention Trial
How many people
18882
Study design
Phase 3 randomised double-blind placebo-controlled, 7 years with 18-year follow-up
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
Prostate cancer 18.4% on finasteride against 24.4% on placebo, 24.8% reduction (95% CI 18.6 to 30.6, P<0.001). Gleason 7-10 in 6.4% against 5.1%, P=0.005. At 18-year follow-up, relative risk 0.70 (0.65 to 0.76) for any cancer and 1.17 (1.00 to 1.37, P=0.05) for high grade
Repeated elsewhere
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. The trial met its primary endpoint decisively and produced a label warning rather than an indication. At up to 18 years, 15-year survival was 78.0% against 78.2% and the hazard ratio for death was 1.02 (95% CI 0.97 to 1.08, P=0.46).
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral tablet, once daily; 5 mg for benign prostatic hyperplasia and 1 mg for androgenetic alopecia
Interval reported. 95% CI 18
Written into the record, not signed off as a reviewed claim.
Overall survival and survival after prostate cancer diagnosis among randomised participants
✓ The study showed what it set out to show
Who was studied
Long-term survival follow-up of PCPT (Thompson 2013)
How many people
18880
Study design
Observational survival follow-up of a randomised cohort, up to 18 years
Compared against
Not recorded for this study
Kind of result
Living longer, or avoiding a major event
What was found
15-year survival 78.0% on finasteride against 78.2% on placebo; unadjusted hazard ratio for death 1.02 (95% CI 0.97 to 1.08, P=0.46). Ten-year survival among men with high-grade cancer 73.0% against 73.6%
Repeated elsewhere
Unreplicated
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. Survival status was ascertained from the Social Security Death Index rather than by active follow-up, and cause of death is not reported. The finding is an absence of difference in all-cause mortality, which is the strongest available answer to the high-grade question and not a direct measurement of prostate-cancer mortality.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral tablet, once daily; 5 mg for benign prostatic hyperplasia and 1 mg for androgenetic alopecia
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
RNAWiki holds 4 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 people◇Read 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.
□Living longer, or avoiding a major eventNo evidence recorded. Death, a heart attack, a stroke, a hospital stay.No registered study measures this.
■What a body can do day to dayEvidence recorded. Walking, dressing, breathing, recovering.2 registered measures of this kind.
■Measured performanceEvidence recorded. How much was lifted, how far was run, how fast.2 registered measures of this kind.
■Symptoms and quality of lifeEvidence recorded. Pain, tiredness, mood, sleep, as the person rated it.1 registered measure of this kind.
■A number that stands in for healthEvidence recorded. Cholesterol, blood sugar, bone density. A stand-in, not the thing itself.7 registered measures of this kind.
■A step measured inside a personEvidence recorded. Something measured in human tissue or human cells.A human record sits on the stored organism ladder.
■AnimalsEvidence recorded. Mice, rats, dogs. Useful for ideas, not proof about people.Stored records in Mouse, Rat. A result in animals says what to test next. It does not say what happens in people.
■Cells in a dishEvidence recorded. Cells or chemistry on a bench, far from a whole body.Stored mechanism abstracts describe steps measured in cells or tissue.
□A guess from softwareNo 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 body◇Read 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.
Where a source records it acting
Skin: Decreases scalp DHT concentrations in men with male pattern hair loss (androgenetic alopecia), as recorded
US prescribing information · 00e934bb-c15b-490a-a852-839689a1231a · read 2026-08-27
Start
Finasteride
What a person takes: Oral tablet, once daily; 5 mg for benign prostatic hyperplasia and 1 mg for androgenetic alopecia.
The measurement behind this step
A conventional film-coated tablet taken once daily with or without food. The same molecule is licensed at a fifth of the dose for male pattern hair loss, because the type II enzyme operates in hair follicles as well as in prostate. Crushed or broken tablets should not be handled by women who are or may become pregnant, because dihydrotestosterone is required for normal development of the male external genitalia.
Getting in
A once-daily tablet with nothing to notice for months
One tablet daily. Unlike the drugs that relax muscle, nothing changes in the first days or weeks, because what has to happen is that the gland gets smaller.
╌╌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
Oral tablet, 5 mg once daily for the prostate indication. Serum dihydrotestosterone falls by approximately 70% within hours, but the tissue consequence — reduced glandular volume — accrues over months. In PLESS the retention and surgery separation accumulated across the full four years.
MTOPS — Medical Therapy of Prostatic Symptoms (NCT00021814) · a recorded source, not a stored snapshot
Reaching the cell
It has to get inside the cell, which nothing else on this page does
Every other drug in this group works on a receptor sitting on the outside of a cell. This one has to cross into the cell, because its target is an enzyme working inside.
──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
5-alpha-reductase is a membrane-bound intracellular enzyme of the endoplasmic reticulum and nuclear membrane, not a cell-surface receptor. Finasteride is a lipophilic steroid analogue and crosses the plasma membrane passively. This is why the laboratory workflow for this drug needs a genuine cell-entry step where the antimuscarinics and alpha-blockers do not.
MTOPS — Medical Therapy of Prostatic Symptoms (NCT00021814) · a recorded source, not a stored snapshot
What it acts on
It occupies the enzyme by pretending to be the reaction halfway through
The enzyme is built to grab testosterone and change it. Finasteride looks enough like testosterone mid-reaction that the enzyme grabs it and then cannot let go quickly.
╌╌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
The 4-azasteroid A-ring is an electronic mimic of the enolate intermediate formed during testosterone reduction, so finasteride binds the enzyme-NADPH complex and forms a slowly dissociating adduct. The label describes it as a competitive and specific inhibitor of type II 5-alpha-reductase; type I, expressed mainly in skin and liver, is inhibited far less, which is the difference from dutasteride.
MTOPS — Medical Therapy of Prostatic Symptoms (NCT00021814) · a recorded source, not a stored snapshot
The change it makes
Dihydrotestosterone falls seventy per cent and the gland stops being told to grow
The hormone that drives prostate growth drops by about seventy per cent. Deprived of it, the glandular tissue slowly involutes and the prostate becomes smaller.
╌╌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
Serum dihydrotestosterone falls approximately 70% on 5 mg daily. Intraprostatic dihydrotestosterone falls further, removing the androgen receptor signalling that sustains epithelial cell survival, and epithelial apoptosis reduces glandular volume. Serum testosterone rises modestly, which is why the drug does not produce the effects of androgen deprivation. Serum PSA falls by about 50% within six months as a direct consequence of the epithelial reduction.
MTOPS — Medical Therapy of Prostatic Symptoms (NCT00021814) · a recorded source, not a stored snapshot
What that does for a person
Two points on the questionnaire, and half as many operations
The symptom questionnaire improves by about two points more than placebo over four years, which is unremarkable. The proportion of men needing a catheter or an operation is roughly halved, which is 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
Symptom score fell 3.3 against 1.3 on placebo over four years. Acute urinary retention 2.8% against 6.6%, surgery 4.6% against 10.1%, with risk reductions of 57% (95% CI 40 to 69) and 55% (41 to 65). In MTOPS, retention and invasive therapy were reduced by finasteride and by combination but not by doxazosin. The cost is sexual: impotence 8.1% against 3.7% and decreased libido 6.4% against 3.4% in year one.
MTOPS — Medical Therapy of Prostatic Symptoms (NCT00021814) · a recorded source, not a stored snapshot
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 take◇Read 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.
international prostate symptom
Measured
Things only a test, a scale or a device shows.
1 repetition maximum strength testing
area under the curve serum t
cmax maximum observed concentration
maximum testosterone concentration
insulin sensitivity
hip bone mineral density
total body fat
urine growth factors level
Meaningful
Things that change how a life goes, not only a number.
walking speed
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 (22)
psa levels
bioequivalence
rate and extend of absorption
bioequivalence based on cmax and auc parameters
prostate volume
who experienced an adverse event
who discontinued treatment due to an adverse event
changes in muscle cross sectional area
apneic threshold a measure of breathing instability
cerebrovascular responsiveness to carbon dioxide
ventilatory responsiveness
carbon dioxide reserve
intraoperative blood loss
hair density
side effects
gut microbiota signature before 5 ari therapy
gut microbiota signature after 5 ari therapy
gut microbiota signature before adt
gut microbiota signature after adt
nuclear area size
These are harms, study-process measures, or names the rules did not recognise. They are shown rather than dropped.
What it would be like to take◇Read from sources, not yet reviewed
How long anything takes
Nine different lengths of time that get confused with each other. None of them is worked out from another.
Before anything is noticed.RNAWiki does not store this separately, and never works it out from another figure on this page.
Before a test result moves.RNAWiki does not store this separately, and never works it out from another figure on this page.
Before performance moves.RNAWiki does not store this separately, and never works it out from another figure on this page.
How long the result was watched.No finished study window is recorded for a study that tested this substance.
How long people took it.How long people actually took it is not stored. The study window is not the same thing.
How long people were followed.Follow-up length is not stored separately. It is never read off the study window, which would be a different thing.
How fast the body clears it. 4.5 hours (range, 3.3 to 13.4 hours) hours
Read from the label, which states: “Mean terminal half-life in plasma was 4.5 hours (range, 3.3 to 13.4 hours; n=12).”
How long effects linger.RNAWiki does not store this separately, and never works it out from another figure on this page.
Beyond the studies. Nothing is recorded about the long term.
The longest finished study sets the edge of what anyone measured.
A study window is not how long people took it, and neither is how long they were followed. Where RNAWiki holds only one of the three, it shows one.
What is missing or unclear◇Read 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.
Men with a demonstrably enlarged prostate, in whom the aim is to change the course of the condition rather than to relieve the symptom today. It works over months, not hours.
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.
What the label states about particular groups
On pediatric, the label states: “Safety and effectiveness in pediatric patients have not been established.”
US prescribing information · cdde1382-a995-4f53-9497-7724d5e25b66 · read 2026-08-30
On older people, the label states: “Of the total number of subjects included in a long-term efficacy and safety study, 1480 and 105 subjects were 65 and over and 75 and over, respectively.”
US prescribing information · cdde1382-a995-4f53-9497-7724d5e25b66 · read 2026-08-30
On people who are pregnant, the label states: “The fetal effects of maternal finasteride exposure during the period of embryonic and fetal development were evaluated in the rhesus monkey (gestation days 20 to 100), in a species and development period more predictive of specific effects in humans than the studies in rats and rabbits.”
US prescribing information · cdde1382-a995-4f53-9497-7724d5e25b66 · read 2026-08-30
On people who are breastfeeding, the label states: “8.3 Females and Males of Reproductive Potential Infertility Females Finasteride is not indicated for use in females.”
US prescribing information · cdde1382-a995-4f53-9497-7724d5e25b66 · read 2026-08-30
On people with reduced liver function, the label states: “Caution should be exercised in the administration of finasteride in those patients with liver function abnormalities, as finasteride is metabolized extensively in the liver [see ].”
US prescribing information · cdde1382-a995-4f53-9497-7724d5e25b66 · read 2026-08-30
On people with reduced kidney function, the label states: “No dosage adjustment is necessary in patients with renal impairment [see ] .”
US prescribing information · cdde1382-a995-4f53-9497-7724d5e25b66 · read 2026-08-30
Where the result stopped carrying
The prostate-cancer prevention indication, which the trial supported and the high-grade signal prevented
Saw palmetto as a natural equivalent, in the largest and best-dosed trial of it
Any expectation that the symptom questionnaire would show this drug's advantage — it does not, and the hard endpoints do
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 take◇Read 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.
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 (10)
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.
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.
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 take◇Read 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
Prescription only
❝ 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 tablet, once daily; 5 mg for benign prostatic hyperplasia and 1 mg for androgenetic alopecia
✎ 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
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Suppression classes recorded: S3.
No source is stored against this line.
What is in the pack
A conventional film-coated tablet taken once daily with or without food. The same molecule is licensed at a fifth of the dose for male pattern hair loss, because the type II enzyme operates in hair follicles as well as in prostate. Crushed or broken tablets should not be handled by women who are or may become pregnant, because dihydrotestosterone is required for normal development of the male external genitalia.
✎ 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 take◇Read 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
Sexual adverse effects dominate and are on-target: impotence 8.1% against 3.7% on placebo, decreased libido 6.4% against 3.4% and decreased ejaculate volume 3.7% against 0.8% in year one of the four-year trial. The label carries the PCPT high-grade prostate cancer finding as a warning, states that PSA falls by about 50% and must be interpreted accordingly, and notes breast changes including breast cancer reports in post-marketing use. Whether sexual effects persist after discontinuation in a minority of men remains disputed and has never been the subject of a randomised trial designed to answer it.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
MTOPS — Medical Therapy of Prostatic Symptoms (NCT00021814) · a recorded source, not a stored snapshot
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.
Finasteride appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 5880 reaction mentions were counted. One report can name several reactions.
The recorded terms (10)
erectile dysfunction — 1098 reaction mentions
sexual dysfunction — 925 reaction mentions
depression — 811 reaction mentions
anxiety — 722 reaction mentions
cognitive disorder — 541 reaction mentions
libido decreased — 516 reaction mentions
loss of libido — 373 reaction mentions
fatigue — 367 reaction mentions
gynaecomastia — 277 reaction mentions
insomnia — 250 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 unclear◇Read 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 tablet, once daily; 5 mg for benign prostatic hyperplasia and 1 mg for androgenetic alopecia
✎ 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
The same molecule is licensed at a fifth of the dose for male pattern hair loss, because the type II enzyme operates in hair follicles as well as in prostate. Crushed or broken tablets should not be handled by women who are or may become pregnant, because dihydrotestosterone is required for normal development of the male external genitalia.
✎ 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
102 products list this as an active ingredient in the United States drug directory. 98 of them contain it and nothing else.
FDA National Drug Code directory · 71610-520 · read 2026-08-29
They are sold as aerosol, foam, capsule, paste, powder, tablet and tablet, coated, taken oral and topical.
FDA National Drug Code directory · 71610-520 · read 2026-08-29
The regulator's established pharmacologic class for it is 5-alpha reductase inhibitor [epc] and 5-alpha reductase inhibitors [moa].
FDA National Drug Code directory · 71610-520 · read 2026-08-29
78 published labels name it as an active ingredient. 75 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · cdde1382-a995-4f53-9497-7724d5e25b66 · read 2026-08-29
Those labels are classed as human otc drug and human prescription drug.
US prescribing information · cdde1382-a995-4f53-9497-7724d5e25b66 · read 2026-08-29
1 marketed supplement label lists this ingredient, classed as botanical.
Those labels carry all other 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.
Finasteride is tablets, film coated at 1 mg, recorded as prescription product; fda label in effect 2017-07-28 in the United States.
US prescribing information · 00e934bb-c15b-490a-a852-839689a1231a · read 2026-08-27
Recorded price in US: 0.0426–0.06839 USD per one unit as the pricing file counts it — a tablet, capsule, patch or single item, across 38 priced products whose strengths and pack forms differ, 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 take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
Self-experiment planning is not offered for a prescription or clinician-supervised medicine. The questions below are for a clinician or pharmacist.
Questions worth asking
Which of the trials of Finasteride studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read 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 small symptom-score margin means a small clinical effect — the same two-point margin accompanies halved retention and surgery here and no change in retention for alfuzosin
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 high-grade cancer excess represents excess deaths — eighteen years of follow-up found no difference in overall survival or in survival after diagnosis
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 composite progression endpoints let two drug classes be compared — MTOPS shows doxazosin and finasteride at 39% and 34% on the composite and completely divergent on catheters and operations
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 saw palmetto delivers the same mechanism in a natural form — a 369-man trial at three times the commercial dose favoured placebo by 0.79 points
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 unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
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 Finasteride 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 people◇Read 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.
Retention and surgery both roughly halved over four years
In plain words
Three thousand men took finasteride or placebo for four years. Ten per cent of the placebo group needed an operation against five per cent on the drug, and seven per cent went into urinary retention against three per cent.
What was measured
Four-year incidence of acute urinary retention and of BPH-related surgery, finasteride versus placebo
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
PLESS randomised 3,040 men with moderate-to-severe symptoms and enlarged glands to finasteride 5 mg or placebo for four years. Surgery for benign prostatic hyperplasia was needed by 152 of 1,503 in the placebo group (10%) and 69 of 1,513 on finasteride (5%), a 55% risk reduction (95% CI 41 to 65). Acute urinary retention developed in 99 (7%) against 42 (3%), a 57% reduction (95% CI 40 to 69). The label states the same figures as 10.1% against 4.6% for surgery and 6.6% against 2.8% for retention. Prostate volume fell and flow rate rose, both P<0.001. This is the only entry in this file where an outcome a patient would recognise as serious — a catheter, an operation — is halved by a drug, and the numbers come from a four-year randomised trial rather than from a post hoc composite.
Written into the record, not signed off as a reviewed claim
The symptom-score margin is two points, the same as every alpha-blocker here
In plain words
On the questionnaire, finasteride beat placebo by two points on a thirty-four point scale over four years. That is no better than the alpha-blockers manage in twelve weeks. The difference is in what else happened.
What was measured
Mean change in symptom score over four years against placebo, compared with the alpha-blocker registration trials in this file
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
In PLESS, mean symptom score decreased 3.3 points on finasteride and 1.3 on placebo among men who completed the study, P<0.001 — a treatment effect of 2.0 points on a 34-point scale. For comparison within this file: alfuzosin delivered 2.0, 2.0 and 1.9 points across its three registration trials; silodosin 2.9 in both of its; tamsulosin 2.8 and 1.5. Finasteride is not better on the questionnaire and takes four years rather than four hours to get there. What separates it is that the same trial halved retention and surgery, and the alpha-blocker trials that measured those outcomes did not. Symptom score and disease course are different endpoints, and this pair of results is the clearest demonstration in urology that improving one does not imply improving the other.
Written into the record, not signed off as a reviewed claim
MTOPS: the alpha-blocker did not reduce retention or surgery and this drug did
In plain words
A three-thousand-man trial compared placebo, an alpha-blocker, finasteride and both together over four and a half years. On the composite score all the active arms looked similar. On catheters and operations, the alpha-blocker did nothing.
What was measured
Risk reduction for overall clinical progression, and separately for acute urinary retention and invasive therapy, by arm
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
MTOPS followed 3,047 men for a mean 4.5 years. Overall clinical progression — defined as a 4-point rise in AUA symptom score, acute urinary retention, incontinence, renal insufficiency or recurrent urinary tract infection — fell 39% on doxazosin (P<0.001) and 34% on finasteride (P=0.002), with combination at 66% (P<0.001), significantly better than either alone. The decisive sentence concerns the hard endpoints: "The risks of acute urinary retention and the need for invasive therapy were significantly reduced by combination therapy (P<0.001) and finasteride (P<0.001) but not by doxazosin." A composite endpoint dominated by a symptom-score threshold can make two drugs look equivalent while one of them is changing the course of the disease and the other is not.
Written into the record, not signed off as a reviewed claim
The prevention trial hit its endpoint and produced a warning, not an indication
In plain words
Nearly nineteen thousand men were randomised for seven years to see whether finasteride prevents prostate cancer. It did — by about a quarter. It also found more high-grade tumours in the treated group, and the result became a label warning rather than a new use.
What was measured
Seven-year prevalence of prostate cancer and of Gleason 7-10 disease, finasteride versus placebo
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The Prostate Cancer Prevention Trial randomised 18,882 men aged 55 and over with normal digital rectal examination and PSA of 3.0 ng/mL or lower to finasteride 5 mg or placebo for seven years, with prevalence of prostate cancer as the primary endpoint. Cancer was detected in 803 of 4,368 evaluable men on finasteride (18.4%) and 1,147 of 4,692 on placebo (24.4%), a 24.8% reduction in prevalence (95% CI 18.6 to 30.6, P<0.001). Tumours of Gleason grade 7 to 10 were more common on finasteride: 280 of 757 tumours (37.0%) against 237 of 1,068 (22.2%), P<0.001; or 6.4% of treated men against 5.1% of placebo men, P=0.005. The current US label carries the Gleason 8-10 figure as 1.8% against 1.1%. A trial that met its primary endpoint decisively, in nearly nineteen thousand men, and whose result appears on the label as a warning is a rare object, and the reason is that the field could not agree whether the high-grade excess was real disease or a detection artefact of a shrunken gland.
Written into the record, not signed off as a reviewed claim
Eighteen years later, the survival curves are on top of each other
In plain words
The high-grade cancer finding hung over this drug for a decade. When the same men were followed for up to eighteen years, fifteen-year survival was 78.0% on finasteride and 78.2% on placebo.
What was measured
Fifteen-year overall survival and hazard ratio for death, with up to 18 years of follow-up on the randomised cohort
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Thompson and colleagues followed the 18,880 randomised PCPT participants through October 2011 using the Social Security Death Index. Prostate cancer was diagnosed in 989 of 9,423 on finasteride (10.5%) and 1,412 of 9,457 on placebo (14.9%), relative risk 0.70 (95% CI 0.65 to 0.76, P<0.001). High-grade cancer occurred in 333 (3.5%) against 286 (3.0%), relative risk 1.17 (95% CI 1.00 to 1.37, P=0.05) — the confidence interval now touching unity. Deaths numbered 2,538 on finasteride and 2,496 on placebo; 15-year survival was 78.0% against 78.2%, unadjusted hazard ratio for death 1.02 (95% CI 0.97 to 1.08, P=0.46). Among men with high-grade cancer, 10-year survival was 73.0% against 73.6%. The excess of high-grade histology did not translate into an excess of deaths over eighteen years, which is the outcome that decides whether a grading artefact matters.
Written into the record, not signed off as a reviewed claim
It halves the PSA, which is a diagnostic problem rather than a side effect
In plain words
Finasteride cuts the PSA blood test result in half within six months. If nobody doubles it back, a rising cancer signal can look like a normal result.
What was measured
Percentage reduction in serum PSA concentration within six months
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The label states that finasteride reduced serum PSA concentration by approximately 50% within six months, and that any confirmed increase in PSA while on treatment may signal the presence of prostate cancer even if the value remains within the range considered normal for untreated men. The correction is a straightforward doubling, and the failure mode is entirely one of communication rather than pharmacology: a PSA measured in a laboratory that does not know the patient is on finasteride, reported to a clinician who does not either, is a normal-looking number that should have triggered a biopsy. This interacts directly with the PCPT finding, because a shrunken gland is easier to biopsy accurately, which is one of the mechanisms proposed for the apparent high-grade excess.
Source
US prescribing information for finasteride tablets 5 mg, Warnings and Precautions and Clinical Pharmacology sections (openFDA drug label endpoint)
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
Sexual adverse effects roughly double, and the label reports them by year
In plain words
In the first year of the four-year trial, impotence was reported by 8.1% on finasteride against 3.7% on placebo, and reduced libido by 6.4% against 3.4%. Reduced ejaculate volume was nearly five times the placebo rate.
What was measured
Year-one incidence of impotence, decreased libido and decreased ejaculate volume against placebo
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The US label reports year-one incidences from PLESS: impotence 8.1% against 3.7%, decreased libido 6.4% against 3.4%, decreased volume of ejaculate 3.7% against 0.8%. These are on-target effects rather than idiosyncratic ones: dihydrotestosterone is the androgen that mediates much of male sexual function, and lowering it by 70% is the drug's entire mechanism. The label reports the rates by year because in the pivotal trial they were highest in year one and fell thereafter, which is a real pattern and also the pattern a differential-dropout artefact would produce. The question of whether a minority of men experience effects persisting after discontinuation has been the subject of label revisions and continuing dispute, and no randomised trial has been designed to resolve it.
Source
US prescribing information for finasteride tablets 5 mg, Adverse Reactions section, four-year PLESS data (openFDA drug label endpoint)
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
Saw palmetto, the supplement sold as its natural equivalent, has a negative trial
In plain words
Saw palmetto is marketed as a natural 5-alpha-reductase inhibitor, the same mechanism as finasteride. A 369-man trial at up to three times the usual dose found placebo did slightly better.
What was measured
Change in AUA symptom index over 72 weeks, escalating-dose saw palmetto extract versus placebo
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The CAMUS trial randomised 369 men to escalating doses of saw palmetto extract or to placebo for 72 weeks, reaching three times the usual commercial dose. The AUA symptom index fell 2.20 points on extract and 2.99 points on placebo — a difference of 0.79 points favouring placebo, one-sided P = 0.91. The trial is included on this page because the proposed mechanism for saw palmetto is inhibition of the identical enzyme, which makes it the closest thing to a natural equivalent this drug has, and because the dose escalation removes the usual objection that commercial preparations are too weak. The mechanism was never the difficulty with saw palmetto; the outcome data were.
This order is fixed in code and does not count clicks or time on the page.
What is not here
3 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.
What it may clash with — found nothing in the sources checked.
Other ways to the same goal — 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 type II 5-alpha-reductase inhibitor that lowers serum dihydrotestosterone by about 70% and shrinks the gland rather than relaxing it: over four years in 3,040 men it improved the symptom score by only 3.3 points against 1.3 on placebo, and in the same trial cut acute urinary retention from 7% to 3% (57% risk reduction, 95% CI 40 to 69) and surgery from 10% to 5% (55%, 41 to 65) — the only drug on this page whose small symptom margin is accompanied by a halved rate of hard outcomes.
Recorded evidence blocks (12)
Q2
What did Finasteride's largest trial (54459 people) and its longest (15 years) measure?
54459 people in Finasteride's largest registered study, 15 years in its longest registered window, measuring Comparison of Biomarkers Between Treatment Arms: Percentage Change of Tumor Cells Exhibiting Detectable Staining Within Gleason Grade 3 (GG3) Biomarker Subgroups at Prostatectomy. ClinicalTrials.gov · 2026-09-01
19 phase2, 16 phase1, 11 phase3, 8 phase4, 4 na, 2 early phase1, 2 na or unstated; NCT01342367; 2026-02. Last human test completed 2022, NCT04032067.
Interpretation These counts include studies where Finasteride 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
phase2
19
phase1
16
phase3
11
phase4
8
na
4
early phase1
2
2 more recorded rows
na or unstated
2
Last recorded human testNCT04032067
2022-03-17
recorded 2026-09-01 · last checked 2026-09-04
Q3
From mouse to human: where has Finasteride shown biomarker?
Comparison of Biomarkers Between Treatment Arms: Percentage Change of Tumor Cells Exhibiting Detectable Staining Within Gleason Grade 3 (GG3) Biomarker… — the recorded outcome words.
Show the evidence
mouse
mechanism-only
rat
mechanism-only
humanNCT00438464
biomarker; Comparison of Biomarkers Between Treatment Arms: Percentage Change of Tumor Cells Exhibiting Detectable Staining Within Gleason Grade 3 (GG3) Biomarker Subgroups at Prostatectomy; 56
recorded 2026-09-01 · last checked 2026-09-04
Q4
7 of Finasteride's trials stopped: accrual/recruitment, funding/business, other?
accrual/recruitment (3), funding/business (3) and other (1): Finasteride's stop wording, clustered. ClinicalTrials.gov · 2026-09-01
"Change of practice pattern. Green light laser"; 7 of 56 registered studies
Show the evidence
Trial
NCT00564460
withdrawn; "Change of practice pattern. Green light laser"
NCT00600691
terminated; "Did not achieve enrollment goal and decided to terminate early"
NCT01534351
terminated; "Business Reasons"
NCT01585441
terminated; "This study was terminated early due to lack of enrollment."
NCT02248701
terminated; "Enrollment difficulties"
NCT02483195
withdrawn; "PI indicating she was withdrawing her study submission due to lack of funding as of 6/20/2016"
1 further recorded trialNCT02548117
withdrawn; "Funding was not available."
recorded 2026-09-01 · last checked 2026-09-04
Q5
Human studies of Finasteride used Finasteride Tablets 5 mg — over how long?
15 recorded entries; human; also "Finasteride Tablets 5 mg", "Proscar Tablets 5 mg", "Proscar® Tablets 5 mg"
Show the evidence
human
NCT00648791
Finasteride Tablets 5 mg
NCT00648791
Proscar Tablets 5 mg
NCT00650377
Proscar® Tablets 5 mg
NCT00835666
Finasteride 5 mg tablets
NCT00835796
PROSCAR® 5mg tablets
NCT00870480
Finasteride 5 mg Tablet, single dose
9 more recorded rows
humanNCT00870480
Proscar® 5 mg Tablet, single dose
humanNCT02483195
5mg Finasteride
humanNCT02502669
Finasteride 23.5 mg tablets
humanNCT02502669
Finasteride 33.5 mg tablets
humanNCT04945226
Finasteride 1mg Tablet
humanNCT05611593
Propecia 1Mg Tablet
humanNCT06001619
Finasteride 5 MG
humanNCT06590779
Finasteride 1mg
humanNCT07731802
Finasteride 1 mg
recorded 2026-09-01 · last checked 2026-09-04
Q6
Finasteride's half-life is 4.5 hours (range, 3.3 to 13.4 hours) — which schedules were studied?
4.5 hours (range, 3.3 to 13.4 hours), the half-life Finasteride's label states. openfda-label · a7a3af01-de3f-4cd4-ba05-a41ca0544ac2 · 2026-08-27
bioavailability 65% (range 26 to 170%) %.
Show the evidence
half life
4.5 hours (range, 3.3 to 13.4 hours) hours; Mean terminal half-life in plasma was 4.5 hours (range, 3.3 to 13.4 hours; n=12).
bioavailability
65% (range 26 to 170%) %; In a study in 15 healthy young male subjects, the mean bioavailability of finasteride 1-mg tablets was 65% (range 26 to 170%), based on the ratio of area under the curve (AUC) relative to an intravenous (IV) reference dose.
metabolism
Metabolism Finasteride is extensively metabolized in the liver, primarily via the cytochrome P450 3A4 enzyme subfamily.
recorded 2026-08-27 · last checked 2026-09-04
Q7
Which of 1 repetition maximum strength testing, apneic threshold a measure of breathing instability and area under the curve serum t did Finasteride's trials measure?
1 repetition maximum strength testing, apneic threshold a measure of breathing instability and area under the curve serum t lead 32 outcome terms across Finasteride's trials. ClinicalTrials.gov · 2026-09-01
Interpretation area under the curve serum t, cmax maximum observed concentration, maximum testosterone concentration, rate and extend of absorption, bioequivalence based on cmax and auc parameters and international prostate symptom follow.
Show the evidence
psa levels
1
1 repetition maximum strength testing
1
bioequivalence
1
area under the curve serum t
1
cmax maximum observed concentration
1
maximum testosterone concentration
1
14 more recorded rows
rate and extend of absorption
1
bioequivalence based on cmax and auc parameters
1
international prostate symptom
1
prostate volume
1
who experienced an adverse event
1
who discontinued treatment due to an adverse event
1
insulin sensitivity
1
hip bone mineral density
1
changes in muscle cross sectional area
1
total body fat
1
walking speed
1
apneic threshold a measure of breathing instability
1
cerebrovascular responsiveness to carbon dioxide
1
ventilatory responsiveness
1
recorded 2026-09-01 · last checked 2026-09-04
Q8
Which of Finasteride's 7 ongoing trials reports first?
Quality of Life Was Measured by the Expanded Prostate Cancer Index Composite (EPIC) Hormonal Health-related Quality of Life Questionnaire; Apneic threshold- a measure of breathing instability; latest 2032-03-31
Show the evidence
Trial
NCT01342367
"Feasibility of Hormones and Radiation for Intermediate or High Risk Prostate Cancer"; n 74; "Quality of Life Was Measured by the Expanded Prostate Cancer Index Composite (EPIC) Hormonal Health-related Quality of Life Questionnaire"; 2026-02
NCT02703220
"Sleep Apnea in Elderly"; n 100; "Apneic threshold- a measure of breathing instability"; 2027-12-31
NCT04288427
"5-Alpha Reductase 2 as a Marker of Resistance to 5ARI Therapy"; n 120; "Finasteride treatment effect on lower urinary tract symptom improvement by urinary symptom score"; 2026-11-30
NCT06001619
"Prostate Medication, Metabolism and Gut Microbiota"; n 100; "Gut microbiota signature before 5-ARI therapy"; 2026-12-31
NCT06944145
"New Treatment Strategies and Epigenetic Biomarker for Management of Benign Prostatic Hyperplasia"; n 242; "Clinical response to at 12 months after study enrollment"; 2030-08-31
NCT07731802
"Finasteride and Cutibacterium"; n 40; "Cutibacterium skin load"; 2027-08-31
1 further recorded trialNCT07742553
"Testosterone Therapy With or Without Finasteride After Spinal Cord Injury: TRT-SCI Trial"; n 300; "Change in lower limb fat-free mass"; 2032-03-31
recorded 2026-09-01 · last checked 2026-09-04
Q9
Which 22 trials of Finasteride posted no result?
Posted no result
22 of 22 completed trials
Registrations
NCT00021814, NCT01133444, NCT01133457, NCT00648791, NCT00650377 and NCT00870480, and 16 more
Completion dates
oldest 2001-11-30; newest 2022-03-17
Show the evidence
Trial
NCT00021814
2001-11-30
NCT01133444
2002-05
NCT01133457
2002-05
NCT00648791
2004-10
NCT00650377
2004-10
NCT00870480
2004-11
14 further recorded trials
NCT00871247
2004-11
NCT01264289
2006-11
NCT01264302
2006-11
NCT00759135
2008-05
NCT01052870
2009-12
NCT00003323
2010-03
NCT01381510
2010-08
NCT01376258
2010-12
NCT00542243
2012-12
NCT01174953
2013-03
NCT06282731
2017-04-27
NCT02502669
2017-06-06
NCT06601205
2017-06-16
NCT04848181
2020-07-09
Q10
At the median, Finasteride's trials enrolled 47.5 people — anything larger?
Median enrolment
47.5
Largest enrolment
54459
Registered trials counted
56
Q11
What do 5880 spontaneous reports say about Finasteride — 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.
Finasteride appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 5880 reaction mentions were counted: erectile dysfunction 1098; sexual dysfunction 925; depression 811; anxiety 722. open-targets-adr · CHEMBL710 · 2026-06-24
Show the evidence
erectile dysfunction
1098
sexual dysfunction
925
depression
811
anxiety
722
cognitive disorder
541
libido decreased
516
4 more recorded rows
loss of libido
373
fatigue
367
gynaecomastia
277
insomnia
250
recorded 2026-06-24 · last checked 2026-09-04
Q12
Finasteride and cytochrome P450 and Cytochrome P450: shared by which compounds?
cytochrome P450 and Cytochrome P450 appear in Finasteride's recorded interaction sentences, 2 in all. openfda-label+europepmc · 2026-08-20
Interpretation drug_interactions
Show the evidence
Cytochrome P450drug_interactions
7 DRUG INTERACTIONS 7.1 Cytochrome P450-Linked Drug Metabolizing Enzyme System No drug interactions of clinical importance have been identified.
cytochrome P450drug_interactions
Finasteride does not appear to affect the cytochrome P450-linked drug metabolizing enzyme system.
recorded 2026-08-20 · last checked 2026-09-04
Q13
What is recorded about Finasteride and IGF-1?
"The in vitro results demonstrated that when BPH-1 cells were grown in monoculture, treatment with finasteride did not induce cell death and stimulated the expression of pro-proliferative signaling molecules, while in the presence of fibroblasts containing c-Jun, finasteride treatment repressed epithelial cell proliferation, the level of…" — where Finasteride and IGF-1 appear together. Europe PMC · pathway abstract search · 2017-02-14
IGF-1, NAD+; PMID 28196103, 8654202
Show the evidence
IGF-1PMID 28196103
"The in vitro results demonstrated that when BPH-1 cells were grown in monoculture, treatment with finasteride did not induce cell death and stimulated the expression of pro-proliferative signaling molecules, while in the presence of fibroblasts containing c-Jun, finasteride treatment repressed epithelial cell proliferation, the level of IGF-1 in the medium, and the activation of downstream…"
NAD+PMID 8654202
"In addition, NAD-dependent enzymes in cytosolic, microsomal, and mitochondrial fractions were capable of oxidizing omega-aldehyde finasteride to omega-oic acid finasteride."
recorded 2017-02-14 · last checked 2026-09-04
Where it is registeredIdentifiers, relations and other names
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
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✓ public claims reviewed: 0 reviewed claim(s); drafts are never rendered
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