Reference

Compare peptides

Two to four compounds, field by field: identity, United States regulatory status, and what kinds of documents are on file. The table records differences. It does not rank them.

Compound 1

Compound 2

Compound 3 (optional)

Compound 4 (optional)

No winner, no score, no recommendation. Counts describe how many documents of each kind Therapept has indexed — not how well a compound works, and not how much has been published overall.

Link to this comparison: /compare?peptides=ru58841,pyrilutamide,clascoterone

Side-by-side comparison of RU58841, Pyrilutamide, Clascoterone
Identity
	RU58841	Pyrilutamide	Clascoterone
Class	Nonsteroidal arylhydantoin androgen-receptor antagonist, studied as a topical solution and supplied as a research chemical	Investigational topical nonsteroidal androgen-receptor antagonist	Topical androgen-receptor inhibitor (cortexolone 17α-propionate), supplied as a 1% cream
Also listed as	RU 58841, RU-58841, PSK-3841, HMR-3841	KX-826, KX826, Pyrilutamide topical	Winlevi, CB-03-01, Cortexolone 17α-propionate, Breezula
Molecular formula	C17H18F3N3O3	Not recorded	C24H34O5
Molecular weight	369.34 g/mol	Not recorded	402.5 g/mol
CAS	154992-24-2	Not recorded	Not recorded
PubChem CID	132981	Not recorded	Not recorded
Sequence length	Not recorded	Not recorded	Not recorded
Data caveat	PSK-3841 and HMR-3841 refer to the same molecule. Full caveat	None recorded	None recorded
United States regulatory status
Status	No FDA-approved product	Investigational	FDA-approved drug substance
FDA application	None recorded	None recorded	NDA 213433 (WINLEVI) — approved 26 August 2020
Compounding	No FDA compounding entry recorded	No FDA compounding entry recorded	No FDA compounding entry recorded
WADA	Not named in this record	Not named in this record	Not named in this record
Research profile
Research purpose	Topical androgen-receptor blockade (unpublished trials)	Topical androgen-receptor blockade	Topical androgen-receptor inhibition for AGA
Proposed mechanism	Binds the androgen receptor and was designed as a rapidly metabolised topical drug to limit systemic exposure. A 2026 human study detected parent drug in blood after a topical dose, so the local-only assumption needs qualification.	A nonsteroidal androgen-receptor antagonist applied to the scalp, intended to reduce androgen signalling in follicle cells. The clinical advantage over existing treatments is not established.	Blocks androgen receptors in the skin. The hair-loss hypothesis is that local blockade reduces follicular androgen signalling. The acne approval does not establish a hair-growth mechanism.
Human evidence	Two completed human trials registered under PSK-3841 in the early 2000s, with no published results. A 2026 study in six men characterised metabolism and systemic exposure.	Phase 2 trials in men and women and a Phase 3 trial in Chinese men are registered; the Phase 2 studies are listed as completed. No approved product.	A Phase 3, vehicle-controlled trial in men with androgenetic alopecia completed in January 2026. No peer-reviewed hair-loss results were indexed at this review.
Evidence tier	Phase 2 trials registered or reported	Phase 3 trials registered or reported	Phase 3 trials registered or reported
Known safety concerns	Systemic exposure has been demonstrated after topical administration. No published human safety dataset from the completed trials is available. Research-chemical supply is not pharmaceutical-grade; identity, purity and sterility are not guaranteed by an approval.	Topical androgen-receptor blockade may still produce systemic effects; the trials are designed to measure this. Phase 3 safety data are not available here as a peer-reviewed report. Long-term safety is unknown.	The acne label lists local skin reactions; the product is applied to the skin, not injected. Systemic androgen suppression is a theoretical concern with any topical antiandrogen; the hair-loss trial was designed to measure it. Hair-loss safety data are not available here as a peer-reviewed report.
Evidence gaps	Any published efficacy result from the completed trials. A human safety dataset and long-term outcomes. Whether the demonstrated systemic exposure has meaningful hormonal effects. Independent quality standards for commercially supplied material.	Peer-reviewed Phase 3 efficacy and safety results. Whether topical delivery avoids meaningful systemic androgen blockade. Durability and any regulatory decision.	Peer-reviewed Phase 3 efficacy and safety results in androgenetic alopecia. Whether scalp androgen blockade produces hair benefit without meaningful systemic effects. Long-term safety and durability.
Head-to-head evidence	No published head-to-head trial against finasteride or any other hair-loss treatment.	No published head-to-head trial against finasteride or minoxidil.	No published head-to-head trial against finasteride, minoxidil or pyrilutamide.
Named pathways	Androgen receptor · DHT signalling · Follicular miniaturisation	Androgen receptor · DHT signalling · Follicular miniaturisation	Androgen receptor · DHT signalling · Follicular miniaturisation
Evidence on file
Records	3Open evidence file	2Open evidence file	2Open evidence file
Human-interventional records	3	2	1
Human-observational records	0	0	0
Animal records	0	0	0
In-vitro records	0	0	0
Reviews	0	0	0
Regulatory documents	0	0	1
Earliest indexed	2005	2022	2022
Latest indexed	2026	2024	2026

Every identity and regulatory value above is taken from the compound’s record, where its sources are listed. Evidence counts are derived from the published evidence file at build time. A missing class means no document of that kind is indexed — not that none exists.

Overlapping pathways

Named in the mechanism discussion for at least two of these compounds: Androgen receptor · DHT signalling · Follicular miniaturisation.

Shared biology is not shared evidence. No claim of synergy is made here, and overlapping pathways do not mean the compounds have been studied together.