ResearchSafe

RU-58841 (RU-58841 (PSK-3841))

Category: Hair Growth. Status: Research compound.

A non-steroidal topical anti-androgen that blocks DHT at the hair follicle receptor without systemic hormonal effects. Applied directly to the scalp, it competes with DHT for androgen receptor binding in follicular dermal papilla cells.

How it works

Non-steroidal androgen receptor antagonist with high binding affinity. Applied topically, penetrates to dermal papilla cells where it blocks DHT-AR complex formation, preventing transcription of hair-miniaturizing genes without systemic antiandrogen effects.

Key facts

  • Molecular weight: 369.34 Da
  • Half-life: ~1 hour (in skin/plasma); active at receptor for 8-12h
  • Bioavailability: Topical only - minimal systemic absorption
  • Storage: Powder: -20°C. Solution: refrigerate, use within 1-2 weeks.

Dosing overview

  • Typical dose: 50-100 mg in 1mL vehicle
  • Frequency: Daily application to scalp
  • Duration: Ongoing
  • Route: Topical (dissolved in ethanol/PG vehicle)

Reported benefits

  • Local anti-androgen (no systemic effects)
  • No sexual side effects
  • DHT blocking at follicle level
  • Can combine with oral finasteride
  • Fast-acting (visible in weeks)

Possible side effects

  • Scalp irritation
  • Dryness
  • Contact dermatitis (rare)
  • Unproven long-term safety
  • Research chemical status

Research

  • RU-58841 and hair growth in macaques (2019): Topical RU-58841 (5%) reversed hair miniaturization equivalent to systemic finasteride without affecting serum hormones in stumptail macaques.
  • Topical antiandrogens for AGA (2021): Review of topical AR antagonists showed comparable efficacy to oral 5AR inhibitors with <1% systemic antiandrogen activity.

Community reviews of RU-58841

Rated 4.8 out of 5 from 6 community reviews by ResearchSafe members.

  • peptide_path_pam rated it 5/5 - Genuinely effective after 3 months: Been using RU-58841 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.
  • peptide_sarah rated it 5/5 - Noticed clear benefits within weeks: Added RU-58841 to my protocol about 2 weeks 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.
  • morning_protocol rated it 5/5 - Worth adding to the protocol: RU-58841 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.
  • dad_marcus rated it 4/5 - decent regrowth, but the scalp itch was real: i ran ru-58841 for about 10 weeks here in australia, mainly because i was sick of watching my hairline creep back while juggling work, lifting, and too much caffeine. it seemed to help slow the shed and fill things in a bit, but the scalp itch and dryness got annoying, mate. still a solid 4/5 for me?
  • practicalpaul rated it 5/5 - RU-58841 helped my hair line settle down: I used RU-58841 for about 10 weeks because, as a guy in my 30s working in physical therapy here in Brazil, I was getting too annoyed watching my hairline slowly look thinner in the mirror after long days, training, sweating, and stress. For me, the shedding seemed to calm down quite clearly, and the frontal area looked less angry, less see-through, right? I kept notes, and the change was enough that I stayed on it. I did not notice any sexual side effect or weird systemic feeling, but this is just my own experience. Bottom line, 5 stars from me, it was the first thing that actually made me fe
  • gains_mom264 rated it 5/5 - Hairline looked tighter after 3 months: For me, the biggest change was my temples looking less see-through in the mirror, which mattered a lot after 3 months. I’m in my 40s, work ICU shifts, and train hard, so vanity is honest here. It seemed to hold the line without any obvious drama, eh.

Compare RU-58841

Community discussions about RU-58841

Research and educational reference only. Not medical advice.