Finasteride: Pills vs Topical, Sexual Side Effects and Pregnancy Rules, by the Trials and the Label

Finasteride 1 mg is the FDA-approved pill for male pattern hair loss, in men only. What the trials show, the sexual and mental-health warnings on the label, topical sprays, pregnancy handling, and pairing it with minoxidil.

By Kymata Health Editorial Last checked For everyone

Key takeaways

5 points
  • Finasteride 1 mg (Propecia) is indicated for male pattern hair loss in men only; it is not indicated for women and is contraindicated in pregnancy1.
  • In two 1-year trials of 1,553 men, finasteride improved hair by every measure used while placebo users kept losing hair2.
  • In the label's 1-year trials, 3.8% of men on finasteride reported a sexual side effect vs 2.1% on placebo; a meta-analysis of 15 trials found a 1.66-fold risk15.
  • The label lists sexual dysfunction that continued after stopping, depression and suicidal ideation among post-marketing reports1.
  • No topical finasteride is FDA-approved; the FDA has warned about compounded topical versions3.

Guides in this hub

3 guides
  1. Finasteride Sexual Side Effects and Post-Finasteride Syndrome: What the Trials, the Label and the Reviews SayIn trials, sexual side effects on finasteride were uncommon and mostly resolved. The label also lists cases that continued after stopping. What is known, what is not, and when to stop and call.
  2. Topical vs Oral Finasteride: What the Spray Trial Shows and Why US Topicals Are CompoundedA finasteride spray beat placebo in a 24-week European trial and looked similar to tablets. In the US, no topical version is FDA-approved, and the FDA has warned about compounded ones.
  3. Finasteride and Minoxidil Together: What Combination Trials Show for Men's Hair LossThe two drugs work in different ways, and trials that paired them found more men with marked improvement than either alone, with similar side effects. What that evidence covers, and what combination pills add.

Researched and written by Kymata Health Editorial; sources cited inline. Drawn from the studies and documents cited below. Educational only, not medical advice.

What finasteride is

Finasteride blocks type II 5-alpha-reductase, the enzyme that turns testosterone into DHT, the hormone behind pattern hair loss1. Propecia (finasteride 1 mg once daily) is indicated for male pattern hair loss in men only, and efficacy at the temples (bitemporal recession) has not been established1.

The label says daily use for 3 months or more is generally needed before benefit is seen, and that stopping reverses the effect within 12 months1.

What the trials show

In two 1-year trials of 1,553 men aged 18 to 41, finasteride improved hair counts, photographs and patient and investigator ratings, while placebo users kept losing hair; the trials were led by researchers at Merck, Propecia's original maker2. The label reports improvement over placebo as early as 3 months, maintained over 5 years1.

In a 2022 network meta-analysis of trials in men, 5 mg oral minoxidil led on hair counts at 24 weeks, and 1 mg finasteride led at 48 weeks9.

Sexual and mental-health side effects

In the label's 1-year trials (945 men on finasteride, 934 on placebo), decreased libido affected 1.8% vs 1.3%, erectile dysfunction 1.3% vs 0.7% and ejaculation disorder 1.2% vs 0.7%; they resolved in men who stopped and in most who continued1. A meta-analysis of 15 randomized trials (4,495 men) found a 1.66-fold risk of sexual dysfunction with finasteride 1 mg5.

Post-marketing reports, which cannot establish how often something happens, include sexual dysfunction that continued after stopping, male infertility or poor semen quality, depression, and suicidal ideation and behavior1. A 2020 review of so-called post-finasteride syndrome concluded that current studies can neither confirm nor rule it out as a distinct condition6. More detail: finasteride sexual side effects. For thoughts of self-harm, get help right away (in the US, call or text 988).

Pregnancy, handling and women

Finasteride is contraindicated in women who are or may be pregnant, because it may cause abnormalities of a male fetus's external genitalia1. Women who are or may be pregnant should not handle crushed or broken tablets; the coating on whole tablets prevents contact during normal handling1.

In a year-long trial of 137 postmenopausal women, finasteride 1 mg did not increase hair growth or slow thinning compared with placebo8. Our finasteride for women guide covers the off-label evidence.

Topical finasteride

No topical finasteride is FDA-approved. The FDA has warned about compounded topical products sold by compounders and telemedicine platforms, citing adverse-event reports such as erectile dysfunction, anxiety, depression and suicidal ideation, and a risk of transfer to others3. In a 24-week European trial of 458 men, run largely by the spray's developer, a finasteride spray beat placebo on hair counts (20.2 vs 6.7 more hairs) and was numerically similar to tablets4. Compared in depth: topical vs oral finasteride.

Finasteride with minoxidil

In a meta-analysis of 5 randomized trials, finasteride plus topical minoxidil gave better photographic scores and more men with marked improvement than either drug alone, with similar side effects7. See finasteride and minoxidil together and the minoxidil page.

PSA and prostate cancer

Finasteride lowers PSA, so tell anyone checking your PSA that you take it; a confirmed rise while on it should be evaluated1. The label also says 5-alpha-reductase inhibitors may increase the risk of high-grade prostate cancer1.

Guides for men and for women

For men: finasteride for men's hair loss and dutasteride vs finasteride. For women: finasteride for women. Both men's and women's hair loss hubs cover the other options.

Find the evidence

Ask our graded human trials about a goal, a grade, a trial size, two supplements or a medicine. Answers are assembled on your device from the rows.

Evidence finder

3,342 trial rows · 869 interaction rows

14 graded trial rows on hair loss, across 10 supplements. Best grade among rows showing a benefit: C.

Verdicts: 14 improved.

Grades of the 14 rows: C 4D 10

Strongest row showing a benefit, per supplement

  1. Purple nutsedge (Cyperus rotundus)Grade C

    Pain and redness after laser hair removal

    Improved · 153 people · RCT · 2022 · 1 more matching row

  2. Rosemary OilGrade C

    Hair count in pattern hair loss (androgenetic alopecia)

    Improved · 100 people · RCT · 2015 · 1 more matching row

  3. Pumpkin seed oilGrade C

    Hair count in male pattern hair loss

    Improved · 76 people · RCT · 2014

Assembled from 14 graded trial rows when this page was built.

Fixed sentence templates filled from our rows; every line links to its row. Not medical advice.

Where to buy

Clinics and services

  • Happy Head: An online hair-loss clinic for men and women. A dermatologist reviews your online consultation and decides whether to prescribe; options include standalone oral finasteride and minoxidil, and custom topicals and capsules that combine them. Its custom formulas are compounded, so they are not FDA-approved, and the FDA has warned about compounded topical finasteride. Happy Head lists custom formulas at $59 to $119 a month (checked Oct 17, 2026).

    Start a Happy Head consultation (paid link, opens in new tab)

  • MangoRx: An online men's health clinic. Its Grow chewable combines oral minoxidil 2.5 mg and finasteride 1 mg with biotin and vitamin D3, prescribed after an online consultation. It is compounded, so it is not FDA-approved, and oral minoxidil for hair loss is off-label. MangoRx lists Grow starting at $90 a month.

    Read our review

Regulatory and legal notes

  • Propecia (finasteride 1 mg) is indicated for male pattern hair loss in men only and is contraindicated in pregnancy1.
  • There is no FDA-approved topical finasteride; in 2025 the FDA warned health care providers, compounders and consumers about compounded topical finasteride3.

References

Every study and document cited on this page, numbered as in the text.

Sources

9 sources
  1. 1PROPECIA (finasteride) tablets, film coated: prescribing information. DailyMed, U.S. National Library of Medicine, 2024.
  2. 2Finasteride in the treatment of men with androgenetic alopecia. Finasteride Male Pattern Hair Loss Study Group. J Am Acad Dermatol, 1998. PMID 9777765
  3. 3FDA alerts health care providers, compounders and consumers of potential risks associated with compounded topical finasteride products. U.S. Food and Drug Administration, 2025.
  4. 4Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia: a phase III, randomized, controlled clinical trial. J Eur Acad Dermatol Venereol, 2022. PMID 34634163
  5. 5Adverse Sexual Effects of Treatment with Finasteride or Dutasteride for Male Androgenetic Alopecia: A Systematic Review and Meta-analysis. Acta Derm Venereol, 2019. PMID 30206635
  6. 6Post-finasteride syndrome. An Bras Dermatol, 2020. PMID 32317131
  7. 7The Efficacy and Safety of Finasteride Combined with Topical Minoxidil for Androgenetic Alopecia: A Systematic Review and Meta-analysis. Aesthetic Plast Surg, 2020. PMID 32166351
  8. 8Lack of efficacy of finasteride in postmenopausal women with androgenetic alopecia. J Am Acad Dermatol, 2000. PMID 11050579
  9. 9Relative Efficacy of Minoxidil and the 5-α Reductase Inhibitors in Androgenetic Alopecia Treatment of Male Patients: A Network Meta-analysis. JAMA Dermatol, 2022. PMID 35107565

Dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Prescription options need a licensed clinician. Talk to your clinician or pharmacist before starting anything new, especially if you take prescription medicines, are pregnant or breastfeeding.

Educational only. Not medical advice. Some links earn us a commission: kymatahealth.com/affiliate-disclosure.