ResearchSafe

Finasteride (Finasteride (Propecia/Proscar))

Category: Hair Growth. Status: FDA Approved (hair loss & BPH).

The first-line FDA-approved treatment for male pattern hair loss. Selectively inhibits type II 5-alpha reductase, reducing scalp DHT levels by ~60-70% to slow or reverse follicular miniaturization.

How it works

Selectively inhibits type II 5-alpha reductase (predominant in hair follicles), reducing conversion of testosterone to dihydrotestosterone. Serum DHT decreases ~70%, scalp DHT ~40%, allowing follicle recovery.

Key facts

  • Molecular weight: 372.54 Da
  • Half-life: ~6-8 hours (but DHT suppression lasts 24h)
  • Bioavailability: ~80% oral
  • Storage: Room temperature. Do not handle crushed tablets if pregnant.

Dosing overview

  • Typical dose: 1 mg (hair) or 5 mg (prostate)
  • Frequency: Daily
  • Duration: 12+ months for full assessment
  • Route: Oral tablet

Reported benefits

  • Halts hair loss progression (90% of men)
  • Regrows hair (65% of men)
  • Well-studied long-term safety
  • FDA-approved
  • Available generic
  • Topical option available

Possible side effects

  • Decreased libido (2-3%)
  • Erectile dysfunction (1-2%)
  • Decreased ejaculate volume
  • Gynecomastia (rare)
  • Depression (rare)

Research

  • Finasteride 10-year follow-up (2019): 10-year data showed 86% of treated men maintained or improved hair counts, with only 14% showing continued loss.
  • Topical vs oral finasteride (2022): Topical finasteride 0.25% achieved equivalent hair counts to oral 1mg with 50% less systemic DHT suppression, reducing side effect risk.

Community reviews of Finasteride

Rated 4.6 out of 5 from 5 community reviews by ResearchSafe members.

  • cycle_sage rated it 5/5 - Worth adding to the protocol: Finasteride has been a worthwhile addition. I am data-driven and tracked relevant markers before, during, and after. The improvement is measurable and correlates with the intervention timeline. What sets this apart from some compounds I have tried is the consistency. Benefits did not fluctuate wildly or disappear. They built up and maintained. That gives me confidence in the mechanism. Tolerance has been excellent. Nothing in my bloodwork or subjective experience raised any flags. This is the kind of compound that does its job quietly without causing problems. Exactly what you want.
  • steady_state_stan rated it 4/5 - Genuinely effective after 6 months: Been using Finasteride for about 6 months and the results are clear. Not overnight dramatic, but a steady, consistent improvement that became undeniable by the end of the first month. The mechanism makes sense based on what I have read in the literature, and my subjective experience matches the expected timeline. Benefits built gradually and plateaued at a good level. Side effects were minimal to none at the dose I used. Followed proper protocols for sourcing, storage, and administration. Would recommend to others who have done their research and have realistic expectations.
  • recovery_rachel rated it 5/5 - Noticed clear benefits within weeks: Added Finasteride to my protocol about 2 months ago and it has earned its place. The benefits became noticeable around week 2-3 and have been consistent since. What I appreciate about this compound is the predictability. It does what the research suggests it should do, at roughly the timeline you would expect. No surprises, no dramatic swings, just steady improvement. No notable side effects to report at my dose. Sourcing is always the challenge with research compounds, insist on third-party testing. Storage and reconstitution per standard protocols. Plan to continue.
  • bio_optimal rated it 4/5 - Solid compound with real results: Been using Finasteride for about 3 months and the results are clear. Not overnight dramatic, but a steady, consistent improvement that became undeniable by the end of the first month. The mechanism makes sense based on what I have read in the literature, and my subjective experience matches the expected timeline. Benefits built gradually and plateaued at a good level. Side effects were minimal to none at the dose I used. Followed proper protocols for sourcing, storage, and administration. Would recommend to others who have done their research and have realistic expectations.
  • researcher_humble rated it 5/5 - Eight Weeks, My Hairline Finally Quit Backing Up: I’m 46, on my feet all day as a PA, and my old temple line was starting to bug me every time I caught my reflection in a hospital bathroom in Jersey. I gave finasteride about 8 weeks, mostly because I wanted to stop the slide before it got uglier. For me, the shed calmed down and my hair looked a little fuller around the front, which surprised me. Could be partly placebo, but I was pretty happy with it.

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Community discussions about Finasteride

Research and educational reference only. Not medical advice.