Pyrilutamide — Safety, Research, Risks & Legal Status

Not medical advice. Pyrilutamide is discussed here for informational and harm-reduction purposes only. We do not endorse use, and any dosing context is informational, not a protocol.

Also known as	KX-826; KX-826 tincture 1.0%
Category	Research Chemical
Drug class	Nonsteroidal androgen receptor antagonist (NSAA), topical selective silent antagonist
Developer	Suzhou Kintor Pharmaceuticals (China)
Development stage (US)	Phase 2 ongoing for AGA and acne as of July 2026; no US Phase 3 announced
Development stage (China)	Phase 3 completed for AGA (primary endpoint reached March 2026); Phase 3 acne in progress; approved in China for AGA
Phase 3 hair count result (China, 0.5%)	Approximately 22.73 hairs/cm² increase vs. baseline; met primary endpoint
Sexual side effects	None drug-related reported in Phase 2 or Phase 3 trials to date
US legal status	Not FDA-approved. Classified as an investigational drug in the United States. An FDA IND application was granted in June 2018 and Phase 2 US trials are ongoing; no Phase 3 US trial has been announced as of July 2026. Not available for patient use in the United States outside of a clinical trial. Approved for androgenetic alopecia in China as KX-826 tincture 1.0% following Phase 3 completion. Not a dietary supplement; the compound may be sold as a research chemical in some jurisdictions but this does not constitute approval for human use.

What is Pyrilutamide?

Pyrilutamide (KX-826) is a topically applied nonsteroidal androgen receptor (AR) antagonist developed by Suzhou Kintor Pharmaceuticals (China) for androgenetic alopecia (AGA) and acne. It competitively inhibits dihydrotestosterone (DHT) binding at follicular androgen receptors in the scalp, thereby reducing follicular miniaturization, while leaving systemic DHT largely intact - a mechanistic distinction from 5-alpha-reductase inhibitors such as finasteride. The compound is a selective, high-affinity silent AR antagonist, meaning it occupies the receptor without partial agonist activity. Its topical route is designed to minimize systemic exposure.

How it works

Pyrilutamide binds competitively to the androgen receptor at the scalp follicle, blocking DHT from activating receptor-mediated signaling that drives follicular miniaturization in AGA. Because the drug is applied topically with limited systemic absorption, circulating DHT levels are not materially altered, which is proposed as the basis for its favorable sexual side-effect profile relative to 5-alpha-reductase inhibitors. The compound acts as a silent antagonist, occupying the AR without recruiting transcriptional coactivators.

Background & history

Developed by Suzhou Kintor Pharmaceuticals (China). The US FDA granted IND approval in June 2018; Phase 2 clearance was granted July 2021. In China, a 666-patient, 26-center Phase 3 trial reached its primary endpoint in March 2026. A separate Phase 3 program in China is underway for acne. The compound holds regulatory approval in China for AGA as of the reporting period; US approval remains years away pending completion of Phase 3 and FDA review. Phase 2 US trials for both AGA and acne were ongoing as of July 2026.

What the research says

Clinical evidence exists at Phase 2 (US) and Phase 3 (China) level for AGA, which is more advanced than most compounds in this class. The Chinese Phase 3 trial (666 patients, 26 centers) reported a hair count increase of approximately 22.73 hairs/cm² at the 0.5% twice-daily formulation, reaching its primary endpoint as of March 2026. The US Phase 2 trial reported approximately 10 hairs/cm² increase at 0.5%. Both trials met primary endpoints; the developer characterized results as exceeding expectations. Safety data across trials showed no serious adverse events and no drug-related sexual dysfunction; adverse events were mild and localized (erythema at the application site in fewer than 5% at the 1.0% dose, itching, dry skin, contact dermatitis). These are manufacturer-reported Phase 2 and Phase 3 figures and have not yet undergone full independent peer-reviewed scrutiny in English-language literature as of July 2026. Caution in interpreting single-developer efficacy claims is warranted pending publication of full trial data. Phase 2 trials for acne are underway in the US and Phase 3 development is in progress in China, though efficacy data for this indication are not yet reported publicly. Realistic US market availability is estimated at 2030 at earliest, contingent on a 2-3 year Phase 3 program plus 12-18 month FDA review cycle.

Reported effects

Reduction in hair follicle miniaturization via scalp AR blockade (Phase 3 human data, China)
Increased terminal hair count in AGA in Phase 2 and Phase 3 trials
Maintained systemic DHT levels (topical mechanism; limited systemic absorption)
No drug-related sexual dysfunction reported in clinical trials to date
Potential reduction in androgen-driven sebaceous activity relevant to acne (Phase 2 stage; limited data)

Dosing & administration (informational)

Published clinical trial protocols used 0.5% and 1.0% topical formulations applied twice daily to the scalp. The Chinese Phase 3 trial reporting the 22.73 hairs/cm² result used the 0.5% formulation. These figures are informational descriptions of trial protocols only and do not constitute a prescribing recommendation or personal dosing guidance. Appropriate use requires physician oversight within an approved or investigational framework. Consult a licensed clinician before considering any therapeutic use.

This is general research/context information, not medical advice or a recommended protocol.

Safety & side effects

No serious adverse events reported across Phase 2 and Phase 3 trials as of July 2026
No drug-related sexual dysfunction observed, contrasting with systemic 5-alpha-reductase inhibitors
Mild localized adverse events reported: erythema (less than 5% at 1.0% dose), itching, dry skin, contact dermatitis
Adverse event incidence not significantly different from placebo in Phase 3
Long-term safety data beyond the trial periods are not yet available
No human safety data exist outside of controlled clinical trials; off-label or uncontrolled use carries unknown risk
Not for human use outside a clinical trial in the United States

Drug & supplement interactions

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Who should avoid it

Use outside a clinical trial or physician supervision in the US
Sourcing from unverified gray-market or research chemical vendors (no quality controls)
Concurrent use with other systemic antiandrogens without medical supervision
Application by or to individuals who are pregnant or may become pregnant (androgenic pathway blockade; no reproductive safety data)
Use in pediatric populations (no data)
Assuming the safety profile from controlled trials generalizes to unregulated formulations

How it is commonly combined

No published stacking data exist. Clinical trials evaluated pyrilutamide as monotherapy. Combination with systemic antiandrogens (finasteride, dutasteride, spironolactone, bicalutamide) has not been studied and could compound AR-blocking effects with unpredictable systemic consequences. Combination with minoxidil has not been formally evaluated in published trials, though this is a common clinical question given complementary mechanisms (AR blockade vs. vasodilation/potassium channel). No evidence-based stacking protocols can be offered.

Legal & regulatory. Not FDA-approved. Classified as an investigational drug in the United States. An FDA IND application was granted in June 2018 and Phase 2 US trials are ongoing; no Phase 3 US trial has been announced as of July 2026. Not available for patient use in the United States outside of a clinical trial. Approved for androgenetic alopecia in China as KX-826 tincture 1.0% following Phase 3 completion. Not a dietary supplement; the compound may be sold as a research chemical in some jurisdictions but this does not constitute approval for human use.

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Frequently asked questions

What makes pyrilutamide different from finasteride or dutasteride?

Finasteride and dutasteride inhibit the enzyme 5-alpha-reductase, reducing DHT production systemically throughout the body. Pyrilutamide instead blocks the androgen receptor directly at the scalp follicle via topical application, leaving systemic DHT levels intact. The proposed benefit is avoiding the systemic sexual and hormonal side effects associated with 5-alpha-reductase inhibitors, though head-to-head comparative trial data do not yet exist.

Is pyrilutamide approved or available in the United States?

No. As of July 2026, pyrilutamide is an investigational drug in the US. The FDA granted IND approval in 2018 and Phase 2 trials are underway, but no Phase 3 US trial has been announced. Realistic availability under FDA approval is estimated no earlier than approximately 2030. It is not legally available for patient use outside a registered clinical trial in the United States.

What is the evidence for its efficacy in hair loss?

The strongest evidence comes from a Chinese Phase 3 trial of 666 patients across 26 centers, which reached its primary endpoint in March 2026, reporting approximately 22.73 hairs/cm² increase with the 0.5% twice-daily formulation. A US Phase 2 trial reported approximately 10 hairs/cm². Both results are developer-reported; full peer-reviewed publication of the Phase 3 data was not yet available in the open literature as of July 2026. Results should be interpreted with appropriate weight given they are sponsor-reported.

What dose should I use?

No dosing guidance can be provided here. Clinical trials have used 0.5% and 1.0% topical formulations twice daily, but these are investigational protocols, not prescribing recommendations. Pyrilutamide is not approved for clinical use in the United States. Consult a licensed clinician for any therapeutic decisions.

Has pyrilutamide been studied for acne?

Phase 2 US trials for acne are ongoing and Phase 3 development is in progress in China as of July 2026. No efficacy data for the acne indication have been reported publicly. Evidence for this use is currently too limited to characterize outcomes.

Are there sexual side effects?

No drug-related sexual dysfunction was observed in Phase 2 or Phase 3 clinical trials as of July 2026. This is consistent with the proposed mechanism - topical application limits systemic DHT suppression. However, long-term safety data beyond the trial periods do not yet exist, and the absence of adverse events in controlled trials does not guarantee the same profile in uncontrolled real-world use, particularly with unverified gray-market formulations.

References & further reading

PubMed: pyrilutamide androgen receptor antagonist
PubMed: KX-826 androgenetic alopecia topical antiandrogen
ClinicalTrials.gov: NCT04502901 pyrilutamide safety pharmacokinetics alopecia
ClinicalTrials.gov: NCT06622824 KX-826 efficacy Chinese male AGA
ClinicalTrials.gov: NCT06409650 KX-826 safety female AGA China