RU-58841 for Topical Anti-Androgen Hair Loss Treatment — Skin & Hair
Non-steroidal topical anti-androgen research compound used off-label for androgenetic alopecia, with no regulatory approval.
Overview
RU-58841 (also known as PSK-3841 or HMR-3841) is a non-steroidal anti-androgen developed by Roussel Uclaf in the 1980s for topical treatment of androgen-dependent conditions including androgenetic alopecia, acne, and hirsutism. It acts as a competitive antagonist at the androgen receptor (AR), directly blocking DHT and testosterone binding at the hair follicle without systemic anti-androgen effects when applied topically. In preclinical studies using stumptail macaque monkeys (a validated model for AGA), topical RU-58841 demonstrated significant hair regrowth comparable to or superior to finasteride, with minimal systemic absorption. However, RU-58841 never progressed beyond early clinical development. ProStrakan acquired the rights and initiated Phase 1/2 trials under the name PSK-3841, but development was abandoned — likely due to formulation instability, short shelf life, and concerns about systemic absorption at higher concentrations. Despite no regulatory approval, RU-58841 is widely available through research chemical vendors and grey-market suppliers. Its use represents uncontrolled self-experimentation with a compound that lacks human safety data, standardized manufacturing, or quality assurance.
Indications
- Investigational only: Topical treatment of androgenetic alopecia
- Investigational only: Topical anti-androgen for acne (preclinical)
- NOT approved for any clinical use in any jurisdiction
Mechanism of Action
Competitively binds to the androgen receptor at the hair follicle dermal papilla, blocking DHT and testosterone from binding
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| RU-58841 | 5% solution (50 mg/mL) | Once daily to scalp | Research-only; no validated dosing. Based on preclinical macaque studies |
| RU-58841 | 2-3% solution | Once daily | Lower concentration — may reduce systemic absorption risk |
Safety & Contraindications
- NO human clinical trial safety data available
- No standardized manufacturing — product quality varies dramatically between vendors
- Potential for systemic absorption at higher concentrations — anti-androgenic effects possible
- Chemical instability in solution — degrades rapidly without proper formulation
- Heart palpitations and chest discomfort reported anecdotally by users (unverified)
- Skin irritation and contact dermatitis reported
- Long-term safety completely unknown — no chronic toxicology studies
- STRONG CAUTION: Using an unregulated research chemical with no human safety data carries significant risk