RU58841
RU58841 is a non-steroidal androgen-receptor antagonist developed for topical treatment of androgenetic alopecia and acne, later abandoned in clinical development. It survives as a grey-market research chemical popular among hair-loss forum users seeking DHT blockade at the follicle without systemic anti-androgen exposure.
01 Overview
RU58841 was studied in the 1990s (originally by Roussel-Uclaf) as a topical AR antagonist. It never reached market and its human data is limited to early trials and animal studies. Today it is sold as a powder or pre-mixed solution by research-chemical vendors with no purity guarantees or oversight.
Users apply it hoping for topical-only anti-androgen action. Because no long-term human safety data exists and product quality is unverified, its risk profile is genuinely uncharacterised — reported benefits are almost entirely anecdotal.
02 Mechanism
Competitively binds the androgen receptor in the hair follicle, blocking DHT- and testosterone-driven miniaturisation. Designed for local action with rapid metabolism to limit systemic androgen blockade.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Anecdotal | 25–50 mg/day | Transdermal | Forum-reported 3-5% solution applied to scalp; no validated dosing |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Reduced hair miniaturisationUsers report slowed loss and some regrowth; supported mainly by animal data and self-report. | Variable | Anecdotal | |
| Local androgen blockadeBlocks AR at the scalp in animal models without lowering serum androgens. | Follicle-localised | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Unknown systemic anti-androgen effectSystemic absorption and potential feminising or libido effects are not characterised in humans. | Moderate | Unknown | Unconfirmed | |
| Product impurity and contaminationGrey-market powder may be underdosed, degraded, or contaminated. | Moderate | Common | Anecdotal |