Is Pyrilutamide a Safer Alternative to Oral Antiandrogens like Finasteride?

In recent years, the conversation around hair loss treatments has evolved beyond efficacy to a more critical question: safety. Finasteride, a widely used oral antiandrogen, has long been the standard treatment for androgenetic alopecia (AGA), but concerns about its systemic side effects have motivated researchers to look for safer, localized alternatives. Pyrilutamide (KX-826), a topical antiandrogen currently in clinical trials, has been promoted as one such option. Yet, is it genuinely safer, or are we witnessing another premature rush to crown a “miracle” solution?

Understanding the Mechanisms: How These Drugs Work

Finasteride is a 5-alpha-reductase inhibitor, meaning it blocks the enzyme responsible for converting testosterone into dihydrotestosterone (DHT). Elevated DHT levels contribute to miniaturization of hair follicles in individuals genetically predisposed to AGA. When DHT production decreases, hair follicles are less likely to shrink. However, because finasteride works systemically—it circulates throughout the body—it can interfere with hormonal balance beyond the scalp. Pyrilutamide, on the other hand, belongs to a different pharmacological class known as androgen receptor antagonists. Instead of reducing DHT levels, pyrilutamide competes with DHT for binding at the androgen receptor, primarily within the scalp’s hair follicles. In theory, this targeted approach should mitigate systemic hormonal disruptions. Being topical, pyrilutamide is designed to act locally, with minimal absorption into the bloodstream. However, theory and practice are not always perfectly aligned.

What the Evidence Says: Comparing Finasteride and Pyrilutamide

Finasteride has decades of research behind it and is approved for male pattern hair loss in the US, UK and EU. Post-marketing reports have also identified side effects that regulators now warn about. According to the U.S. Food and Drug Administration’s (FDA) label for Propecia (2012), some patients reported persistent sexual dysfunction even after discontinuing the drug. The UK MHRA (safety review, April 2024; Drug Safety Update, May 2026) states that finasteride is associated with depression, suicidal thoughts and sexual dysfunction 'which may persist after treatment is stopped'. The UK regulator (MHRA, May 2026) advises stopping finasteride 1 mg immediately and contacting a doctor if depression or suicidal thoughts develop. In 2025 the European Medicines Agency confirmed suicidal thoughts as a side effect of finasteride tablets, with a frequency that cannot be estimated. Regulators say the frequency of these reports cannot be estimated from the available data (Propecia prescribing information; EMA 2025), and that they cannot prove finasteride caused them in a given person.

Pyrilutamide’s evidence is comparatively sparse and comes almost entirely from company announcements. In a Chinese Phase II trial run by Kintor Pharmaceutical in 2020–2021 (NCT05940506), **120 men with moderate AGA were treated for 24 weeks with different strengths of pyrilutamide. **The company reported that the group using 0.5% twice daily gained 22.73 hairs per square centimeter from baseline, 15.34 more than placebo; these figures are sponsor-reported and have not been published in a journal. Notably, no serious adverse events were reported, with most side effects being mild scalp irritation. However, this study’s duration—just under six months—does not allow conclusions about long-term safety or systemic absorption.

In May 2023 Kintor reported a U.S. Phase II trial (123 men, NCT05218642): the 0.5% twice-daily group gained about 10 hairs per square centimeter compared with baseline at 24 weeks, but the company did not report a statistically significant difference from placebo. In November 2023 Kintor announced that its China Phase III of the 0.5% tincture (740 men, NCT06126965) did not beat placebo at 24 weeks. In March 2026 the company announced that the Phase III stage of a separate adaptive trial (666 men) met its primary endpoint for a 1.0% tincture, with no drug-related serious adverse events. All of these results are sponsor-reported, and none has been published in a peer-reviewed journal.

Evaluating Safety: The Complexity Behind “Safer”

Describing one drug as “safer” than another requires context. Finasteride’s systemic activity explains both its therapeutic power and its side effects. Pyrilutamide’s localized mechanism appears advantageous in this regard, but we lack data on chronic exposure, cumulative absorption, and potential hormonal feedback mechanisms. Skin permeability can vary greatly between individuals, meaning some users could still experience systemic absorption. Furthermore, most pyrilutamide studies so far exclude women, individuals with hormonal disorders, or older participants, leaving critical safety questions unanswered. The phrase “no serious adverse events” in early trials should be interpreted cautiously. Many medications show benign short-term safety profiles before revealing problems in post-marketing surveillance. The medical community has seen this before, where the absence of immediate toxicity leads to premature optimism.

Finasteride is FDA-approved for male pattern hair loss and has long-term efficacy data. Its safety data are less complete: most trials followed men for a year or less and reported adverse events poorly (Belknap et al., JAMA Dermatol 2015, PMID 25830296), so how often side effects persist after stopping is not known. Pyrilutamide is still investigational and, as of September 2026, is not approved by the FDA or any other regulator. The regulatory gap underscores the uncertainty: while pyrilutamide shows potential, it is too early to confirm whether it truly offers superior safety. The transition from controlled clinical trials to real-world use often exposes risks that are invisible in small-scale studies. For patients and clinicians alike, the takeaway is not that pyrilutamide is unsafe—but that the claim of being a “safer alternative” cannot yet be substantiated. Science demands time, replication, and transparency, and pyrilutamide is still in that critical early stage.

When asked whether pyrilutamide is a safer alternative to oral antiandrogens like finasteride, the honest answer is that nobody knows yet. The topical route offers theoretical safety advantages, and the sponsor reports few systemic side effects in its trials. However, the absence of long-term and independent studies means safety comparisons with finasteride remain speculative. For now, pyrilutamide is an investigational compound that needs further independent study. Until long-term, peer-reviewed evidence emerges, claims of superior safety are unsupported. Material sold online as pyrilutamide is an unregulated research chemical of unverified identity and purity. No reproductive-safety data on pyrilutamide have been published. Antiandrogens as a class can affect the development of a male fetus, so pyrilutamide is not considered appropriate for anyone who is pregnant, may become pregnant or is breastfeeding, and a partner who is or may be pregnant should avoid contact with treated skin. Talk to a doctor or pharmacist before starting, stopping or combining any hair-loss treatment.

References

Kintor Pharmaceuticals Ltd. (2021, July 11). U.S. FDA greenlights Phase II clinical trial for KX-826 to treat androgenetic alopecia. Retrieved from https://en.kintor.com.cn/news_details/1803365218310795264.html

HairScience. (2023, July 19). Kintor announces update on KX-826 (Pyrilutamide) for hair loss. Retrieved from https://hairscience.org/news/kintor-usa-clinical-trial-pyrilutamide-results/

Kintor Pharmaceutical. (2023, May 11). Kintor Pharma announces successful completion of Phase II clinical trial of KX-826 for treatment of androgenetic alopecia in the US. PR Newswire. https://www.prnewswire.com/news-releases/kintor-pharma-announces-successful-completion-of-phase-ii-clinical-trial-of-kx-826-for-treatment-of-androgenetic-alopecia-in-the-us-301822352.html

Kintor Pharmaceutical. Announcement of top-line results of the Phase III clinical trial of KX-826 for male androgenetic alopecia in China (Hong Kong Stock Exchange announcement, 26 November 2023). https://www.marketscreener.com/quote/stock/KINTOR-PHARMACEUTICAL-LIM-111325374/news/Kintor-Pharmaceutical-Limited-Announces-Results-of-Phase-III-Clinical-Trial-of-KX-826-Topline-Treatm-45442274/

Kintor Pharmaceutical. (2026, March 18). Phase III KX-826 tincture 1.0% for AGA reached primary endpoint (company announcement). https://en.kintor.com.cn/news_details/22.html

Perfect Hair Health. (2024, May 9). Pyrilutamide (KX-826) for hair loss: Conflicting study results. Retrieved from https://perfecthairhealth.com/pyrilutamide-kx-826-a-promising-future-treatment-for-hair-loss/

Mysore, V., & Shashikumar, B. M. (2016). Guidelines on the use of finasteride in androgenetic alopecia. Indian Journal of Dermatology, Venereology, and Leprology, 82(2), 128-134. Retrieved from https://ijdvl.com/guidelines-on-the-use-of-finasteride-in-androgenetic-alopecia/

U.S. Food & Drug Administration. (2012). PROPECIA (finasteride) tablets for oral use label. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2012/020788s020s021s023lbl.pdf

Medicines and Healthcare Products Regulatory Agency. (2024, April). Safety review of finasteride: Public Assessment Report. Retrieved from https://assets.publishing.service.gov.uk/media/6825bc05a4c1a40fde4e63e7/Finasteride_PAR_Accessible_1206.pdf

Medicines and Healthcare Products Regulatory Agency. (2026, May 11). Finasteride and dutasteride: updated safety warnings for psychiatric side effects and sexual dysfunction. Drug Safety Update. https://www.gov.uk/drug-safety-update/finasteride-and-dutasteride-updated-safety-warnings-for-psychiatric-side-effects-and-sexual-dysfunction

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Belknap, S. M., Aslam, I., Kiguradze, T., et al. (2015). Adverse event reporting in clinical trials of finasteride for androgenic alopecia: A meta-analysis. JAMA Dermatology, 151(6), 600–606. https://pubmed.ncbi.nlm.nih.gov/25830296/

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