Lower numbers = closer to natural. Higher numbers = more enhanced.
Why this rating?
A topical androgen receptor antagonist in clinical development for androgenetic alopecia. It blocks androgen signalling at the follicle rather than supplying any anabolic effect, so it does not move the natural ceiling. Rated 1 (basically natty).
Overview
A topical androgen receptor antagonist: the same mechanistic idea as RU58841, but actually taken through formal clinical trials. That makes it the most credible member of the topical-antiandrogen category. The results, however, are genuinely mixed: its US Phase 2 failed to separate from placebo, while later and longer Chinese trials reported clear statistically significant benefit.
Important Warnings
- •NOT approved by any regulator: investigational, with an NDA only anticipated in China
- •The evidence is mixed: the 24-week US Phase 2 and a 24-week Chinese Phase 3 failed to beat placebo
- •Headline Phase III efficacy and safety figures are sponsor-reported top-line announcements
- •Consumer-obtained material is a research chemical of unverified concentration, not the trial formulation
- •Prohibited under WADA S0 as a non-approved substance, relevant to tested athletes
- •Its use specifically alongside AAS has never been studied
Purpose & Use Cases
Receptor-Level Blockade Where 5-AR Inhibitors Do Not Apply
Blocking the receptor rather than DHT production means it theoretically covers DHT-derivatives, 19-nors and trenbolone. The compounds finasteride cannot help with. Note this specific application has never been trialled; the trials were in ordinary androgenetic alopecia, not in AAS users.
Avoiding Systemic Antiandrogen Side Effects
The appeal over oral 5-AR inhibitors is the absence of systemic hormonal side effects. Kintor reports a low overall adverse event incidence and specifically no drug-related sexual dysfunction in its Phase III program.
Benefits
- The only topical antiandrogen for hair loss with reported Phase III human data
- Kintor reports its 666-patient Chinese Phase III trial met its primary endpoint
- In a 52-week Chinese trial, the 0.5% twice-daily arm reported +14.46 hairs/cm² from baseline and +9.78 hairs/cm² over placebo (p<0.0001)
- The 1% twice-daily arm reported +15.33 hairs/cm² from baseline and +10.65 hairs/cm² over placebo (p<0.0001)
- Company reports low overall adverse event incidence and no drug-related sexual dysfunction
- Mechanism is independent of 5-alpha-reductase, so it theoretically applies to any androgen
Good to Know
The trial results genuinely conflict: read them carefully
The 123-patient US Phase 2 ran 24 weeks and, while the 0.5% twice-daily group gained around 10 hairs/cm² from baseline, it showed NO significant improvement versus placebo. A 24-week Chinese Phase 3 likewise reported improvement over baseline but no significant change versus placebo. Only the more recent 52-week Chinese trial produced clear separation from placebo. Anyone citing this compound as proven is quoting one arm of a mixed record.
Duration may be the whole story
The pattern across trials is that 24 weeks was not long enough to beat placebo, while 52 weeks was. If that holds, it means realistic expectations are measured in a year, not a few months, and it means short self-experiments will look like failures regardless of whether the drug works.
It is the evidence-backed version of RU58841
Same mechanism, same theoretical advantage over finasteride, but pyrilutamide has actually been through formal clinical trials with published numbers and a regulatory pathway. RU58841 has animal data from the 1990s and community anecdote. If you want a topical antiandrogen, this is the one with data.
Company-reported, China-conducted, not yet approved
The headline Phase III results are top-line announcements from the sponsor, and the pivotal work was conducted in China. NDA submission to the Chinese NMPA was expected in 2026 with possible commercialization in 2027. No Western regulator has reviewed it.
Dosage Guidelines
| Experience Level | Dosage Range |
|---|---|
| Beginner | 1 – 1 applications/day |
| Intermediate | 2 – 2 applications/day |
The concentration matters more than the application count: trials have used 0.25% once daily, 0.5% once daily, 0.5% twice daily and 1% twice daily. 0.5% twice daily is the schedule carried into the later trials, and the 52-week Chinese study also tested 1% twice daily with marginally better numbers. Trial durations were 24 weeks (Phase 2 US, Phase 3 China) and 52 weeks (the more recent Chinese trial), and the duration difference matters, because the 24-week studies did NOT separate from placebo while the 52-week study did. Anyone buying this today is buying from a research-chemical supplier with unverified concentration, not the trial formulation.
Designed as a locally-acting topical antiandrogen. Kintor reports no drug-related sexual dysfunction in its trials, which is the practical proxy for limited systemic androgen blockade, but detailed human pharmacokinetics have not been published in the peer-reviewed literature.
Side Effects
Application site irritation
uncommonLocal irritation, redness or itching at the application site, as with any alcohol-based topical solution.
Reduce application volume or frequency.
Unverified product quality outside trials
commonThe trial data describes a controlled pharmaceutical formulation. What is sold to consumers is a research chemical of unverified concentration and purity, so the trial results do not necessarily transfer to what someone actually applies.
Third-party testing where available. Recognise that the evidence applies to the trial product, not the grey-market one.
Unknown long-term safety
uncommonSafety reporting to date comes from the sponsor rather than from independent long-term surveillance, and the compound has never been marketed. Effects beyond the trial durations are unknown.
No mitigation beyond understanding the limitation.
General Mitigation Strategies
The reported tolerability is good, low overall adverse event incidence and no drug-related sexual dysfunction, which is the main thing people are trying to avoid by choosing a topical over oral finasteride. The two honest caveats are that this safety data is sponsor-reported rather than independently verified, and that consumer-obtained material is not the trial formulation.
Post Cycle Therapy (PCT)
No HPT axis interaction. No PCT implications.
How It Works
Pyrilutamide competes with DHT and testosterone at the androgen receptor within the hair follicle, occupying the receptor without triggering downstream transcription and thereby preventing androgen-driven follicular miniaturization. Because it acts at the receptor rather than on 5-alpha-reductase, it is theoretically indifferent to which androgen is causing the loss. The same argument that drives interest in RU58841, but with human trial data attached.
Hormonal & Androgenic Profile
N/A: an androgen receptor antagonist, not an agonist.
Not an aromatase or estrogen tool.
None: it acts downstream at the receptor rather than on the enzyme. That is the mechanistic argument for using it where finasteride cannot work: DHT-derivatives, 19-nors and trenbolone. This application is theoretical and untested; the trials enrolled ordinary AGA patients, not AAS users.
No documented cardiovascular effect.
Fundamentals
Reference on the practices relevant to Pyrilutamide: how they are done and where they go wrong. Not a recommendation to use it.
Common Stacks
- Pyrilutamide + Minoxidil: independent mechanisms
- Pyrilutamide instead of RU58841 when a topical antiandrogen is wanted, same mechanism, actual trial data
- Consider approved options (minoxidil, finasteride, dutasteride) first
Legal Status
Investigational. Kintor Pharmaceutical has reported meeting its Phase III primary endpoint in China and expects to submit an NDA to the Chinese NMPA in 2026, with commercialization in China anticipated in 2027 if successful. Not approved in the US, EU or anywhere else. Material sold to consumers today comes from research-chemical suppliers, not an approved manufacturer.
Legal status varies by country and changes over time. This is a general summary, not legal advice.
WADA Status
WADA S0 prohibits at all times any pharmacological substance not addressed elsewhere on the List and with no current approval by any governmental regulatory health authority for human therapeutic use, explicitly including drugs under clinical development. Pyrilutamide is still investigational everywhere, so it is caught by S0 despite having no performance-enhancing action.