Does RU58841 work for hair loss?

Honestly: WE DON'T KNOW. The concept (local androgen-receptor blockade) is logical, and in animal models (macaque, hamster, rat) it showed antiandrogen/hair-growth effects. BUT there is no completed, published HUMAN clinical trial, so human efficacy and safety are unproven. Positive user reports are anecdotal and do not substitute for controlled data. Anyone who wants a treatment with proven effect should consider minoxidil + finasteride as the sensible starting combination.

This is not known either. Since there is no human safety study, the side-effect profile, the extent of absorption and the long-term risks are not documented. As an androgen-receptor antagonist, a theoretical systemic antiandrogen effect (libido, mood) is possible if absorbed. On top of that, the purity of "research chemical" sources is unverified. Overall: experimental, unproven and unpredictable – not a validated, safe treatment.

EmergingResearch compound

RU58841

Name: RU58841
Creator: MolekulaX

Nonsteroidal topical androgen-receptor antagonist (PSK-3841), developed by Roussel-Uclaf in the 1980s. NEVER licensed; only ANIMAL data + grey-market anecdote exist, with NO completed human clinical trial. Experimental, unproven and unverified.

Related comparisons

Clascoterone vs Pyrilutamide vs RU58841

WHAT IS RU58841?

Detailed overview

RU58841 (also coded PSK-3841) is a nonsteroidal, topically acting androgen-receptor (AR) antagonist developed by Roussel-Uclaf in the 1980s for the local treatment of acne, androgenetic alopecia and hirsutism. Its theoretical appeal is that it blocks the action of DHT at the level of the hair follicle while having little systemic effect. HOWEVER: the published evidence is EXCLUSIVELY preclinical/animal (Syrian hamster flank-organ and sebaceous-gland model, fuzzy rat, and the stumptail macaque that shows AGA-like balding) – these described a local antiandrogen effect and hair growth in the macaque (PMID 8136306, 7625751, 9449168). THERE IS NO COMPLETED, PUBLISHED HUMAN CLINICAL TRIAL: the agent was never marketed, and its later development (PSK-3841, ProStrakan) was halted. It is a popular "research chemical" in hair-loss communities, but human efficacy and safety are UNPROVEN and the purity of the sources is unverified. This card is therefore an honest presentation of an experimental compound, NOT a treatment recommendation.

Other code

PSK-3841 · RU-58841 (Roussel-Uclaf)

Status

EXPERIMENTAL – never licensed; no completed human trial

Mechanism of action

Nonsteroidal topical androgen-receptor antagonist (local anti-DHT)

Evidence

ONLY animal/preclinical + anecdote – NO human data

Access

Not available as a drug; only unverified grey market

Data console

Lab data

/lab/molecular-data.jsonLIVE
> Classification-
> StructureN/A
> Molecular weightN/A
> Target area-
> Storage2–8°C
> Stability~30 days reconstituted

Safety

Side effects, stop signs, contraindications

Side effects · 4

NO human safety data: the human side-effect profile of RU58841 is unknown, as no completed human clinical trial was conducted/published. All "experience" is anecdotal, from unregulated grey-market use.
Local scalp irritation (anecdotal): user reports mention redness, itching, flaking; this is NOT controlled data.
Theoretical systemic antiandrogen risk: if absorbed, as an AR antagonist it could in theory cause systemic antiandrogen effects (libido, mood, hormonal); there are no human PK/safety data to judge this.
Unverified purity: RU58841 sold as a "research chemical" has unverified identity, purity, dose and contaminants, posing additional unpredictable risk.

Contraindications · 3

NOT a drug, not an approved agent: there is no approved therapeutic indication or dose; human use outside a clinical study cannot be supported.
Pregnancy, breastfeeding, childbearing potential: as an AR antagonist a theoretical risk to male fetal development; strictly avoid.
Any hormone-sensitive condition, unknown history: without human data the risk cannot be assessed, so it cannot be recommended.

Related Hair & Skin

Same therapeutic category

Studies

Related research and clinical findings

J Steroid Biochem Mol Biol. 1994;48(1):55-60. (PRECLINICAL)

RU 58841, a new specific topical antiandrogen: a candidate of choice for the treatment of acne, androgenetic alopecia and hirsutism

Battmann T, Bonfils A, Branche C, et al.

PMID: 8136306Open

Ann N Y Acad Sci. 1995;761:341-343. (PRECLINICAL)

Local inhibition of sebaceous gland growth by topically applied RU 58841

Chen W, Zouboulis CC, Orfanos CE.

PMID: 7625751Open

Skin Pharmacol. 1997;10(3):131-137. (ANIMAL MODEL)

Effects of topical antiandrogen and 5-alpha-reductase inhibitors on sebaceous glands in male fuzzy rats

Chen W, Zouboulis CC, Fritsch M, et al.

PMID: 9449168Open

Have a question about RU58841?

Educational hair and skin info from official sources (PubMed, FDA, EMA). Does NOT replace medical consultation. Talk to a dermatologist!

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MolekulaX Editorial Team·Source-verified · PubMed · FDA · EMA

Updated: June 19, 2026

The information here is strictly for educational and scientific purposes. It does not replace medical advice or clinical consultation, and it does not encourage illegal substance or pharmaceutical use. Data is sourced. When in doubt, consult your doctor.