Finasteride
updated
Oral finasteride 1 mg has large controlled trials for androgenetic alopecia in men. Its best-known result is a placebo-adjusted hair count in a defined vertex area after months of treatment. The evidence applies to male pattern hair loss and the oral product; compounded topical or injected forms have separate exposure and safety questions.
Type II 5-alpha-reductase inhibitor
- Oral Propecia is FDA approved for male pattern hair loss in men
- Reduces scalp and circulating DHT
- Continued treatment is needed to sustain benefit
Has this hair-loss pattern and formulation actually been studied?
The current Propecia label covers oral finasteride 1 mg for male pattern hair loss in men. The pivotal trials enrolled men aged 18 to 41 with mild to moderate androgenetic alopecia, chiefly vertex loss. Sudden shedding, patchy loss, scarring, inflammation, medication-related loss, and nutritional or endocrine causes need a diagnosis rather than an automatic finasteride answer.
The label says efficacy in bitemporal recession has not been established. Its anterior mid-scalp study excluded the bitemporal and frontal hairline areas from hair counts.
A 12-month label study in 137 postmenopausal women did not show benefit. That one null population does not answer every possible use in women, but it does explain why the cited U.S. indication is men only.
Propecia label · oral 1 mg
FDA prescribing information
Organon. PROPECIA (finasteride) tablets prescribing information. Label revised August 2022; DailyMed record updated October 2024.
Defines the men-only oral hair-loss indication, 1 mg schedule, treatment and stopping timeline, pivotal hair-count context, trial sexual-event rates, PSA effects, pregnancy handling, postmarketing events, and interaction record.
- Participants / model
- Men with male pattern hair loss under the labeled indication; pivotal trials chiefly involved men aged 18 to 41
- Treatment
- Finasteride 1 mg oral tablet once daily
- Follow-up
- Current DailyMed record updated October 2024; controlled and extension data through five years with declining follow-up
- Study design
- Regulatory prescribing information
The label does not approve topical finasteride, women, pediatric patients, or bitemporal-recession efficacy.
Read the original sourcePivotal hair trials · JAAD 1998
Randomized controlled trials
Kaufman KD et al. Journal of the American Academy of Dermatology. 1998;39(4 Pt 1):578-589. doi:10.1016/S0190-9622(98)70007-6. PMID: 9777765.
Two trials in 1,553 men found a 107-hair advantage over placebo at one year and a 138-hair advantage at two years in a 5.1 cm² vertex target area with mean baseline count 876.
- Participants / model
- Men aged 18 to 41 with male pattern hair loss
- Treatment
- Oral finasteride 1 mg daily versus placebo
- Follow-up
- One year; 1,215 elected to continue blinded follow-up for year two
- Study design
- Two randomized double-blind placebo-controlled trials with blinded extension
- Funding
- Merck; first author and several investigators were affiliated with Merck Research Laboratories
The reported hair-count difference applies to a fixed vertex circle. Year-two and later placebo groups were much smaller than at randomization.
Read the original sourceWhat does the famous 107-hair result actually mean?
Two one-year trials randomized 1,553 men aged 18 to 41 to oral finasteride 1 mg or placebo. Baseline hair count averaged 876 hairs in a one-inch-diameter, 5.1 cm² circle of active vertex hair loss. At 12 months, finasteride produced a 107-hair advantage over placebo in that circle, with 679 finasteride and 672 placebo participants in the analysis.
| Field | What was measured |
|---|---|
| Population | 1,553 men aged 18 to 41 with mild to moderate vertex androgenetic alopecia |
| Baseline | Mean 876 hairs in the target circle |
| Area | One-inch diameter, 5.1 cm², at active vertex hair loss |
| Year-one comparison | 107 more hairs with finasteride than placebo; 679 versus 672 analyzed |
| Other assessments | Patient reports, investigator ratings, and blinded standardized photographs favored finasteride |
The 107 is a between-group difference, not 107 new hairs guaranteed for every user or spread across the entire scalp. The placebo group continued to lose hair, so the difference includes both regrowth and slower progression.
Pivotal hair trials · JAAD 1998
Randomized controlled trials
Kaufman KD et al. Journal of the American Academy of Dermatology. 1998;39(4 Pt 1):578-589. doi:10.1016/S0190-9622(98)70007-6. PMID: 9777765.
Two trials in 1,553 men found a 107-hair advantage over placebo at one year and a 138-hair advantage at two years in a 5.1 cm² vertex target area with mean baseline count 876.
- Participants / model
- Men aged 18 to 41 with male pattern hair loss
- Treatment
- Oral finasteride 1 mg daily versus placebo
- Follow-up
- One year; 1,215 elected to continue blinded follow-up for year two
- Study design
- Two randomized double-blind placebo-controlled trials with blinded extension
- Funding
- Merck; first author and several investigators were affiliated with Merck Research Laboratories
The reported hair-count difference applies to a fixed vertex circle. Year-two and later placebo groups were much smaller than at randomization.
Read the original sourcePropecia label · oral 1 mg
FDA prescribing information
Organon. PROPECIA (finasteride) tablets prescribing information. Label revised August 2022; DailyMed record updated October 2024.
Defines the men-only oral hair-loss indication, 1 mg schedule, treatment and stopping timeline, pivotal hair-count context, trial sexual-event rates, PSA effects, pregnancy handling, postmarketing events, and interaction record.
- Participants / model
- Men with male pattern hair loss under the labeled indication; pivotal trials chiefly involved men aged 18 to 41
- Treatment
- Finasteride 1 mg oral tablet once daily
- Follow-up
- Current DailyMed record updated October 2024; controlled and extension data through five years with declining follow-up
- Study design
- Regulatory prescribing information
The label does not approve topical finasteride, women, pediatric patients, or bitemporal-recession efficacy.
Read the original sourceWhen should benefit appear, and what happens after stopping?
The label says three months or more of daily use is generally needed before benefit is observed. In the trials, hair-count separation was clear by six months, and the 1,215 men who chose to continue blinded treatment supplied the second-year record. The year-two between-group difference was 138 hairs in the same target circle, but the placebo denominator had fallen to 47, so it is less balanced than year one.
Continued use is recommended to sustain benefit. The label says withdrawal reverses effect within 12 months; in the extension, men switched from finasteride to placebo lost the hair-count increase by the next year.
Five-year label plots have heavy attrition: 323 finasteride participants and only 23 placebo participants entered year five, far fewer than the original randomized population.
Propecia label · oral 1 mg
FDA prescribing information
Organon. PROPECIA (finasteride) tablets prescribing information. Label revised August 2022; DailyMed record updated October 2024.
Defines the men-only oral hair-loss indication, 1 mg schedule, treatment and stopping timeline, pivotal hair-count context, trial sexual-event rates, PSA effects, pregnancy handling, postmarketing events, and interaction record.
- Participants / model
- Men with male pattern hair loss under the labeled indication; pivotal trials chiefly involved men aged 18 to 41
- Treatment
- Finasteride 1 mg oral tablet once daily
- Follow-up
- Current DailyMed record updated October 2024; controlled and extension data through five years with declining follow-up
- Study design
- Regulatory prescribing information
The label does not approve topical finasteride, women, pediatric patients, or bitemporal-recession efficacy.
Read the original sourcePivotal hair trials · JAAD 1998
Randomized controlled trials
Kaufman KD et al. Journal of the American Academy of Dermatology. 1998;39(4 Pt 1):578-589. doi:10.1016/S0190-9622(98)70007-6. PMID: 9777765.
Two trials in 1,553 men found a 107-hair advantage over placebo at one year and a 138-hair advantage at two years in a 5.1 cm² vertex target area with mean baseline count 876.
- Participants / model
- Men aged 18 to 41 with male pattern hair loss
- Treatment
- Oral finasteride 1 mg daily versus placebo
- Follow-up
- One year; 1,215 elected to continue blinded follow-up for year two
- Study design
- Two randomized double-blind placebo-controlled trials with blinded extension
- Funding
- Merck; first author and several investigators were affiliated with Merck Research Laboratories
The reported hair-count difference applies to a fixed vertex circle. Year-two and later placebo groups were much smaller than at randomization.
Read the original sourceHow does the evidence compare with dutasteride and topical minoxidil?
Dutasteride inhibits type I and type II 5-alpha-reductase and is not US approved for hair loss. A direct 24-week trial in 917 men found dutasteride 0.5 mg superior to finasteride 1 mg on target-area hair count, hair width, and frontal photographic assessment, but it did not measure long-term comparative safety or durability.
| Option | Direct evidence | Main limitation |
|---|---|---|
| Oral finasteride 1 mg | Large placebo-controlled trials through two years, with selected long extensions | Best quantified result is vertex-area hair count in men |
| Oral dutasteride 0.5 mg | Beat finasteride 1 mg on several 24-week outcomes in 917 men | US hair use is off-label; 24 weeks is short for durability and uncommon harms |
| Topical minoxidil 5% | A 12-month randomized study in 450 Chinese men compared finasteride, minoxidil, and combination | 428 were evaluated; categorical improvement was 80.5%, 59.0%, and 94.1%, an endpoint unlike the pivotal finasteride hair count |
In the 450-person study, both monotherapies improved its categorical outcome and the combination had the highest response. Its route, endpoint, population, blinding, and tolerability differ from the pivotal vertex hair-count trials.
Dutasteride head-to-head · JAAD 2014
Randomized active- and placebo-controlled trial
Gubelin Harcha W et al. Journal of the American Academy of Dermatology. 2014;70(3):489-498.e3. doi:10.1016/j.jaad.2013.10.049. PMID: 24411083.
Among 917 men, dutasteride 0.5 mg exceeded finasteride 1 mg and placebo on several hair-count, width, and photographic outcomes at 24 weeks.
- Participants / model
- 917 men aged 20 to 50 with androgenetic alopecia
- Treatment
- Three dutasteride doses, finasteride 1 mg, or placebo daily
- Follow-up
- 24 weeks
- Study design
- Randomized active- and placebo-controlled dose-ranging trial
- Funding
- GlaxoSmithKline; three authors were company employees
The study was limited to 24 weeks and does not change US approval status or establish long-term comparative safety.
Read the original sourceFinasteride-minoxidil comparison · 2015
Randomized comparative trial
Hu R et al. Dermatologic Therapy. 2015;28(5):303-308. doi:10.1111/dth.12246. PMID: 26031764.
At 12 months, categorical improvement was reported in 80.5% with finasteride, 59.0% with topical minoxidil, and 94.1% with the combination among 428 evaluated men.
- Participants / model
- 450 Chinese men with androgenetic alopecia; 428 evaluated at treatment end
- Treatment
- Oral finasteride, topical 5% minoxidil, or their combination
- Follow-up
- 12 months
- Study design
- Randomized three-group comparative study
- Funding
- Not stated in the indexed abstract
The categorical improvement endpoint is not directly interchangeable with the pivotal 5.1 cm² hair-count result, and blinding was not described in the abstract.
Read the original sourceDoes a compounded topical product inherit Propecia's approval?
No. FDA states that no topical finasteride formulation is FDA approved. Compounded products do not have FDA-approved labeling and were not reviewed for safety, effectiveness, or quality before marketing. Skin absorption into the bloodstream is expected, so topical does not mean scalp-only.
FDA's April 2025 alert described 32 adverse-event cases reported from 2019 through 2024. That count is a pharmacovigilance signal, not an incidence rate or a causal estimate. The agency also highlighted local irritation and inadvertent transfer to others, including potential pregnancy exposure, as route-specific concerns.
FDA topical-finasteride alert · April 2025
FDA safety communication
US Food and Drug Administration. Potential risks associated with compounded topical finasteride products. April 22, 2025.
States there is no FDA-approved topical finasteride, systemic absorption is expected, and compounded products raise systemic, local, and transfer risks.
- Participants / model
- Consumers using compounded topical finasteride and people exposed through transfer
- Treatment
- Compounded topical finasteride alone or with other ingredients
- Follow-up
- Alert issued April 2025; 32 FAERS cases from 2019 through 2024 discussed
- Study design
- Regulatory safety communication based on approval status and spontaneous reports
The 32 cases are not an incidence rate and do not establish causality.
Read the original sourcePropecia label · oral 1 mg
FDA prescribing information
Organon. PROPECIA (finasteride) tablets prescribing information. Label revised August 2022; DailyMed record updated October 2024.
Defines the men-only oral hair-loss indication, 1 mg schedule, treatment and stopping timeline, pivotal hair-count context, trial sexual-event rates, PSA effects, pregnancy handling, postmarketing events, and interaction record.
- Participants / model
- Men with male pattern hair loss under the labeled indication; pivotal trials chiefly involved men aged 18 to 41
- Treatment
- Finasteride 1 mg oral tablet once daily
- Follow-up
- Current DailyMed record updated October 2024; controlled and extension data through five years with declining follow-up
- Study design
- Regulatory prescribing information
The label does not approve topical finasteride, women, pediatric patients, or bitemporal-recession efficacy.
Read the original sourceDoes more DHT suppression guarantee more hair?
Finasteride preferentially inhibits type II 5-alpha-reductase and reduces conversion of testosterone to dihydrotestosterone in scalp and systemic tissues. A 42-day randomized study in 249 men showed dose-related scalp and serum DHT suppression. That is a mechanistic surrogate, not proof that increasing a dose produces better long-term hair outcomes or a better benefit-risk balance.
The label reports about 65% serum DHT suppression within 24 hours after a 1 mg oral dose and says the relative contribution of scalp versus serum DHT reduction to the hair result is not defined.
Propecia label · oral 1 mg
FDA prescribing information
Organon. PROPECIA (finasteride) tablets prescribing information. Label revised August 2022; DailyMed record updated October 2024.
Defines the men-only oral hair-loss indication, 1 mg schedule, treatment and stopping timeline, pivotal hair-count context, trial sexual-event rates, PSA effects, pregnancy handling, postmarketing events, and interaction record.
- Participants / model
- Men with male pattern hair loss under the labeled indication; pivotal trials chiefly involved men aged 18 to 41
- Treatment
- Finasteride 1 mg oral tablet once daily
- Follow-up
- Current DailyMed record updated October 2024; controlled and extension data through five years with declining follow-up
- Study design
- Regulatory prescribing information
The label does not approve topical finasteride, women, pediatric patients, or bitemporal-recession efficacy.
Read the original sourceScalp and serum DHT study · 1999
Randomized dose-ranging biomarker study
Drake L et al. Journal of the American Academy of Dermatology. 1999;41(4):550-554. PMID: 10495374.
Multiple oral doses reduced scalp and serum DHT over 42 days in men with androgenetic alopecia.
- Participants / model
- 249 men with androgenetic alopecia
- Treatment
- Randomized oral finasteride dose groups and placebo
- Follow-up
- 42 days
- Study design
- Randomized dose-ranging scalp-biopsy and serum biomarker study
- Funding
- Merck-associated authorship
DHT suppression is a mechanistic surrogate and cannot by itself rank long-term hair benefit or safety.
Read the original sourceWhat did randomized trials show about sexual adverse effects?
In the first year of the controlled hair-loss trials, decreased libido was reported by 1.8% with finasteride and 1.3% with placebo; erectile dysfunction by 1.3% and 0.7%; and ejaculation disorder by 1.2% and 0.7%. At least one of those events occurred in 3.8% of 945 finasteride participants and 2.1% of 934 placebo participants.
Drug-related sexual events led 1.2% on finasteride and 0.9% on placebo to stop. The label says events resolved in those who discontinued and in most who continued; each event's reported incidence fell to 0.3% or less by year five. Attrition and continued-treatment selection still matter when interpreting later years.
Propecia label · oral 1 mg
FDA prescribing information
Organon. PROPECIA (finasteride) tablets prescribing information. Label revised August 2022; DailyMed record updated October 2024.
Defines the men-only oral hair-loss indication, 1 mg schedule, treatment and stopping timeline, pivotal hair-count context, trial sexual-event rates, PSA effects, pregnancy handling, postmarketing events, and interaction record.
- Participants / model
- Men with male pattern hair loss under the labeled indication; pivotal trials chiefly involved men aged 18 to 41
- Treatment
- Finasteride 1 mg oral tablet once daily
- Follow-up
- Current DailyMed record updated October 2024; controlled and extension data through five years with declining follow-up
- Study design
- Regulatory prescribing information
The label does not approve topical finasteride, women, pediatric patients, or bitemporal-recession efficacy.
Read the original sourceWhat is known about persistent sexual and mood reports?
The current Propecia label lists voluntary postmarketing reports of sexual dysfunction continuing after discontinuation, male infertility or poor seminal quality, testicular pain, male breast cancer, breast tenderness or enlargement, depression, and suicidal ideation and behavior. Because the exposed population is uncertain, the reports cannot supply frequency or establish that finasteride caused every event.
Propecia label · oral 1 mg
FDA prescribing information
Organon. PROPECIA (finasteride) tablets prescribing information. Label revised August 2022; DailyMed record updated October 2024.
Defines the men-only oral hair-loss indication, 1 mg schedule, treatment and stopping timeline, pivotal hair-count context, trial sexual-event rates, PSA effects, pregnancy handling, postmarketing events, and interaction record.
- Participants / model
- Men with male pattern hair loss under the labeled indication; pivotal trials chiefly involved men aged 18 to 41
- Treatment
- Finasteride 1 mg oral tablet once daily
- Follow-up
- Current DailyMed record updated October 2024; controlled and extension data through five years with declining follow-up
- Study design
- Regulatory prescribing information
The label does not approve topical finasteride, women, pediatric patients, or bitemporal-recession efficacy.
Read the original sourceFDA topical-finasteride alert · April 2025
FDA safety communication
US Food and Drug Administration. Potential risks associated with compounded topical finasteride products. April 22, 2025.
States there is no FDA-approved topical finasteride, systemic absorption is expected, and compounded products raise systemic, local, and transfer risks.
- Participants / model
- Consumers using compounded topical finasteride and people exposed through transfer
- Treatment
- Compounded topical finasteride alone or with other ingredients
- Follow-up
- Alert issued April 2025; 32 FAERS cases from 2019 through 2024 discussed
- Study design
- Regulatory safety communication based on approval status and spontaneous reports
The 32 cases are not an incidence rate and do not establish causality.
Read the original sourceWhich non-hair safety details change care?
Finasteride lowers prostate-specific antigen. In men aged 18 to 41 taking 1 mg, mean PSA fell from 0.7 to 0.5 ng/mL at 12 months. A confirmed rise from the person's lowest value while taking finasteride needs evaluation even if it remains inside a reference range for untreated men.
- People who are pregnant or may become pregnant should not handle crushed or broken tablets because absorption can harm development of external genitalia in a male fetus. Intact tablets are coated for normal handling.
- The high-grade prostate-cancer signal in the label came from men aged 55 or older taking 5 mg daily for seven years, five times the Propecia dose. The label says its significance for men taking 1 mg for hair loss is unknown.
- No clinically important drug interactions were identified in the label's studied set, and finasteride does not appear to affect CYP-linked metabolism. Liver abnormalities still warrant caution because finasteride is extensively metabolized there.
Propecia label · oral 1 mg
FDA prescribing information
Organon. PROPECIA (finasteride) tablets prescribing information. Label revised August 2022; DailyMed record updated October 2024.
Defines the men-only oral hair-loss indication, 1 mg schedule, treatment and stopping timeline, pivotal hair-count context, trial sexual-event rates, PSA effects, pregnancy handling, postmarketing events, and interaction record.
- Participants / model
- Men with male pattern hair loss under the labeled indication; pivotal trials chiefly involved men aged 18 to 41
- Treatment
- Finasteride 1 mg oral tablet once daily
- Follow-up
- Current DailyMed record updated October 2024; controlled and extension data through five years with declining follow-up
- Study design
- Regulatory prescribing information
The label does not approve topical finasteride, women, pediatric patients, or bitemporal-recession efficacy.
Read the original sourceWhich records support these conclusions?
The current Propecia label supplies the indication, timeline, trial tables, maintenance data, and safety provenance. The primary hair-count and DHT reports define efficacy and mechanism. FDA supplies the current topical-compounding status, and direct trials provide the dutasteride and minoxidil comparisons.
Propecia label · oral 1 mg
FDA prescribing information
Organon. PROPECIA (finasteride) tablets prescribing information. Label revised August 2022; DailyMed record updated October 2024.
Defines the men-only oral hair-loss indication, 1 mg schedule, treatment and stopping timeline, pivotal hair-count context, trial sexual-event rates, PSA effects, pregnancy handling, postmarketing events, and interaction record.
- Participants / model
- Men with male pattern hair loss under the labeled indication; pivotal trials chiefly involved men aged 18 to 41
- Treatment
- Finasteride 1 mg oral tablet once daily
- Follow-up
- Current DailyMed record updated October 2024; controlled and extension data through five years with declining follow-up
- Study design
- Regulatory prescribing information
The label does not approve topical finasteride, women, pediatric patients, or bitemporal-recession efficacy.
Read the original sourcePivotal hair trials · JAAD 1998
Randomized controlled trials
Kaufman KD et al. Journal of the American Academy of Dermatology. 1998;39(4 Pt 1):578-589. doi:10.1016/S0190-9622(98)70007-6. PMID: 9777765.
Two trials in 1,553 men found a 107-hair advantage over placebo at one year and a 138-hair advantage at two years in a 5.1 cm² vertex target area with mean baseline count 876.
- Participants / model
- Men aged 18 to 41 with male pattern hair loss
- Treatment
- Oral finasteride 1 mg daily versus placebo
- Follow-up
- One year; 1,215 elected to continue blinded follow-up for year two
- Study design
- Two randomized double-blind placebo-controlled trials with blinded extension
- Funding
- Merck; first author and several investigators were affiliated with Merck Research Laboratories
The reported hair-count difference applies to a fixed vertex circle. Year-two and later placebo groups were much smaller than at randomization.
Read the original sourceScalp and serum DHT study · 1999
Randomized dose-ranging biomarker study
Drake L et al. Journal of the American Academy of Dermatology. 1999;41(4):550-554. PMID: 10495374.
Multiple oral doses reduced scalp and serum DHT over 42 days in men with androgenetic alopecia.
- Participants / model
- 249 men with androgenetic alopecia
- Treatment
- Randomized oral finasteride dose groups and placebo
- Follow-up
- 42 days
- Study design
- Randomized dose-ranging scalp-biopsy and serum biomarker study
- Funding
- Merck-associated authorship
DHT suppression is a mechanistic surrogate and cannot by itself rank long-term hair benefit or safety.
Read the original sourceFDA topical-finasteride alert · April 2025
FDA safety communication
US Food and Drug Administration. Potential risks associated with compounded topical finasteride products. April 22, 2025.
States there is no FDA-approved topical finasteride, systemic absorption is expected, and compounded products raise systemic, local, and transfer risks.
- Participants / model
- Consumers using compounded topical finasteride and people exposed through transfer
- Treatment
- Compounded topical finasteride alone or with other ingredients
- Follow-up
- Alert issued April 2025; 32 FAERS cases from 2019 through 2024 discussed
- Study design
- Regulatory safety communication based on approval status and spontaneous reports
The 32 cases are not an incidence rate and do not establish causality.
Read the original sourceDutasteride head-to-head · JAAD 2014
Randomized active- and placebo-controlled trial
Gubelin Harcha W et al. Journal of the American Academy of Dermatology. 2014;70(3):489-498.e3. doi:10.1016/j.jaad.2013.10.049. PMID: 24411083.
Among 917 men, dutasteride 0.5 mg exceeded finasteride 1 mg and placebo on several hair-count, width, and photographic outcomes at 24 weeks.
- Participants / model
- 917 men aged 20 to 50 with androgenetic alopecia
- Treatment
- Three dutasteride doses, finasteride 1 mg, or placebo daily
- Follow-up
- 24 weeks
- Study design
- Randomized active- and placebo-controlled dose-ranging trial
- Funding
- GlaxoSmithKline; three authors were company employees
The study was limited to 24 weeks and does not change US approval status or establish long-term comparative safety.
Read the original sourceFinasteride-minoxidil comparison · 2015
Randomized comparative trial
Hu R et al. Dermatologic Therapy. 2015;28(5):303-308. doi:10.1111/dth.12246. PMID: 26031764.
At 12 months, categorical improvement was reported in 80.5% with finasteride, 59.0% with topical minoxidil, and 94.1% with the combination among 428 evaluated men.
- Participants / model
- 450 Chinese men with androgenetic alopecia; 428 evaluated at treatment end
- Treatment
- Oral finasteride, topical 5% minoxidil, or their combination
- Follow-up
- 12 months
- Study design
- Randomized three-group comparative study
- Funding
- Not stated in the indexed abstract
The categorical improvement endpoint is not directly interchangeable with the pivotal 5.1 cm² hair-count result, and blinding was not described in the abstract.
Read the original sourceStudies and sources
Propecia label · oral 1 mg
FDA prescribing information
Organon. PROPECIA (finasteride) tablets prescribing information. Label revised August 2022; DailyMed record updated October 2024.
Defines the men-only oral hair-loss indication, 1 mg schedule, treatment and stopping timeline, pivotal hair-count context, trial sexual-event rates, PSA effects, pregnancy handling, postmarketing events, and interaction record.
- Participants / model
- Men with male pattern hair loss under the labeled indication; pivotal trials chiefly involved men aged 18 to 41
- Treatment
- Finasteride 1 mg oral tablet once daily
- Follow-up
- Current DailyMed record updated October 2024; controlled and extension data through five years with declining follow-up
- Study design
- Regulatory prescribing information
The label does not approve topical finasteride, women, pediatric patients, or bitemporal-recession efficacy.
Read the original sourcePivotal hair trials · JAAD 1998
Randomized controlled trials
Kaufman KD et al. Journal of the American Academy of Dermatology. 1998;39(4 Pt 1):578-589. doi:10.1016/S0190-9622(98)70007-6. PMID: 9777765.
Two trials in 1,553 men found a 107-hair advantage over placebo at one year and a 138-hair advantage at two years in a 5.1 cm² vertex target area with mean baseline count 876.
- Participants / model
- Men aged 18 to 41 with male pattern hair loss
- Treatment
- Oral finasteride 1 mg daily versus placebo
- Follow-up
- One year; 1,215 elected to continue blinded follow-up for year two
- Study design
- Two randomized double-blind placebo-controlled trials with blinded extension
- Funding
- Merck; first author and several investigators were affiliated with Merck Research Laboratories
The reported hair-count difference applies to a fixed vertex circle. Year-two and later placebo groups were much smaller than at randomization.
Read the original sourceScalp and serum DHT study · 1999
Randomized dose-ranging biomarker study
Drake L et al. Journal of the American Academy of Dermatology. 1999;41(4):550-554. PMID: 10495374.
Multiple oral doses reduced scalp and serum DHT over 42 days in men with androgenetic alopecia.
- Participants / model
- 249 men with androgenetic alopecia
- Treatment
- Randomized oral finasteride dose groups and placebo
- Follow-up
- 42 days
- Study design
- Randomized dose-ranging scalp-biopsy and serum biomarker study
- Funding
- Merck-associated authorship
DHT suppression is a mechanistic surrogate and cannot by itself rank long-term hair benefit or safety.
Read the original sourceFDA topical-finasteride alert · April 2025
FDA safety communication
US Food and Drug Administration. Potential risks associated with compounded topical finasteride products. April 22, 2025.
States there is no FDA-approved topical finasteride, systemic absorption is expected, and compounded products raise systemic, local, and transfer risks.
- Participants / model
- Consumers using compounded topical finasteride and people exposed through transfer
- Treatment
- Compounded topical finasteride alone or with other ingredients
- Follow-up
- Alert issued April 2025; 32 FAERS cases from 2019 through 2024 discussed
- Study design
- Regulatory safety communication based on approval status and spontaneous reports
The 32 cases are not an incidence rate and do not establish causality.
Read the original sourceDutasteride head-to-head · JAAD 2014
Randomized active- and placebo-controlled trial
Gubelin Harcha W et al. Journal of the American Academy of Dermatology. 2014;70(3):489-498.e3. doi:10.1016/j.jaad.2013.10.049. PMID: 24411083.
Among 917 men, dutasteride 0.5 mg exceeded finasteride 1 mg and placebo on several hair-count, width, and photographic outcomes at 24 weeks.
- Participants / model
- 917 men aged 20 to 50 with androgenetic alopecia
- Treatment
- Three dutasteride doses, finasteride 1 mg, or placebo daily
- Follow-up
- 24 weeks
- Study design
- Randomized active- and placebo-controlled dose-ranging trial
- Funding
- GlaxoSmithKline; three authors were company employees
The study was limited to 24 weeks and does not change US approval status or establish long-term comparative safety.
Read the original sourceFinasteride-minoxidil comparison · 2015
Randomized comparative trial
Hu R et al. Dermatologic Therapy. 2015;28(5):303-308. doi:10.1111/dth.12246. PMID: 26031764.
At 12 months, categorical improvement was reported in 80.5% with finasteride, 59.0% with topical minoxidil, and 94.1% with the combination among 428 evaluated men.
- Participants / model
- 450 Chinese men with androgenetic alopecia; 428 evaluated at treatment end
- Treatment
- Oral finasteride, topical 5% minoxidil, or their combination
- Follow-up
- 12 months
- Study design
- Randomized three-group comparative study
- Funding
- Not stated in the indexed abstract
The categorical improvement endpoint is not directly interchangeable with the pivotal 5.1 cm² hair-count result, and blinding was not described in the abstract.
Read the original sourceWhy is Finasteride in S tier?
The S tier reflects an approved oral medicine with large randomized hair-loss trials and long follow-up. It applies to the studied male androgenetic-alopecia population and 1 mg oral product, not every hair-loss pattern, every population, or every finasteride formulation.
read Finasteride in the reptides guide, chapter 12: 12 pages, free to read.