Is clascoterone suitable for both men and women?

Hair loss affects men and women differently. Not only do the patterns of hair thinning differ, but so do the hormonal causes, emotional impacts, and—most importantly—the way treatments interact with the body. Given this diversity, an obvious question arises: could a single active ingredient like clascoterone work for both sexes?

Types of alopecia: different causes, different challenges

Androgenetic alopecia is the most common form of hair loss in both men and women, but it presents very differently. In men, hair loss typically begins at the temples or crown, often progressing to baldness. In women, hair tends to thin more diffusely, especially along the center part, but rarely leads to complete baldness.

In addition to androgenetic alopecia, there are other forms of hair loss: alopecia areata (autoimmune-related), traction alopecia (from tight hairstyles or extensions), and telogen effluvium (temporary loss due to stress or hormonal changes). Clascoterone is being developed specifically for androgenetic alopecia, a condition linked to a hormone called dihydrotestosterone (DHT), which is a derivative of testosterone. In genetically predisposed individuals, this hormone binds to androgen receptors in the scalp and causes hair follicles to shrink over time, producing increasingly finer hairs until growth stops. This process affects both men and women, although DHT levels and follicular sensitivity differ by sex. That's where clascoterone comes in.

What is clascoterone, and why is it generating interest?

Clascoterone is a molecule that acts as an androgen receptor antagonist in the skin. Simply put, it competes with DHT at receptors in the area where it is applied. The manufacturer's pharmacokinetic data show very little of the drug reaching the bloodstream, which is the basis for describing it as acting locally. That is what makes it different in principle from treatments like finasteride, which alters hormone production throughout the body. The best-known formulation of clascoterone is "Winlevi," a cream approved by the FDA in 2020 for treating acne in people aged 12 and over, male and female. Its scalp version, "Breezula," is still in development for androgenetic alopecia and is not approved for hair loss anywhere. The interest in clascoterone lies in the prospect of a topical anti-androgen that does not carry systemic hormonal effects — a prospect that the hair-loss trials still have to confirm.

What does the science say about its use in men?

The sponsor, Cassiopea, ran a phase II randomized, double-blind, placebo-controlled study of topical clascoterone solution in men with androgenetic alopecia, with around 400 participants aged 18 to 55 treated for 12 months across several concentrations including 7.5%. Results were assessed using standardized photographs and counts of terminal hairs (the thick, visible ones) in a defined area of the scalp. According to the company's reported results, men treated with clascoterone showed a statistically significant increase in terminal hair count compared with placebo, though the size of the effect was described as modest, and no significant systemic side effects were reported over that period. These figures come from the sponsor's own announcements rather than a peer-reviewed publication, which is a real limitation when judging them.

Two much larger phase III trials in men have since completed: NCT05910450 (703 men) and NCT05914805, known as SCALP2 (762 men), both testing clascoterone solution in male pattern hair loss. The company has reported positive top-line results and says it intends to file for regulatory approval; until a regulator reviews the full data, clascoterone remains investigational for hair loss in men as well as in women.

What about women?

While Winlevi is FDA-approved for acne in women, scalp use is not approved for either sex. Cassiopea has reported results from a phase II study in roughly 290 women with female-pattern hair loss: on the company's account, the 5% solution was the only arm to reach statistical significance, and only in the subgroup of women under 30. That is a narrow finding from a subgroup analysis, not a demonstration that the drug works in women generally, and it has not been published in a peer-reviewed journal. No clascoterone hair-loss trial in women appears on ClinicalTrials.gov, and the phase III programme so far has enrolled men only.

Unlike spironolactone—which is used off-label in women for hair loss and does affect hormones throughout the body—clascoterone is intended to act on the follicle locally. If that holds up in trials, it could matter for women of reproductive age or those who cannot use systemic anti-androgens. It has not yet been shown to hold up.

Is it truly safe for both sexes?

Clascoterone's safety record so far comes almost entirely from acne treatment. In pharmacokinetic studies submitted for its 2020 FDA approval, clascoterone cream was applied to the skin and blood levels were measured; the results showed minimal systemic absorption even with repeated application, which is why the label carries no systemic hormonal warnings. That approval covers a 1% cream on facial skin. Scalp use differs in several ways that matter: the concentrations tested for hair loss are higher, the area treated is different, and treatment would be indefinite rather than for a course of acne. The hair-loss trials, not the acne data, are what would have to establish long-term scalp safety, and those data are not public yet.

So, is it suitable for both men and women?

Clascoterone is not approved for hair loss in anyone, and its use on the scalp is off-label and investigational for both men and women. The evidence is strongest in men — two completed phase III trials with sponsor-reported positive results — and thinnest in women, where the only data is a company-reported phase II with significance confined to one subgroup. Its localized mechanism is the reason researchers think it may suit patients who cannot take treatments that affect hormones throughout the body, but that advantage is a rationale rather than a proven result.

Talk to a doctor or dermatologist before starting, stopping or combining clascoterone. In women, a hair-loss diagnosis should come first, since several treatable conditions cause thinning that resembles female-pattern hair loss; and if you are pregnant, planning a pregnancy or breastfeeding, tell your clinician, because the effects of a topical anti-androgen in pregnancy have not been established. Any product sold as scalp clascoterone today is either the acne cream used off-label or an unregulated compounded preparation, and neither has been assessed for this purpose.

References

Cosmo Pharmaceuticals / Cassiopea. Clascoterone solution phase II and phase III programme in androgenetic alopecia — results reported in company announcements; not peer-reviewed at the time of writing.

Clinical trial registration (NCT05910450). A Study to Evaluate the Efficacy and Safety of Clascoterone Solution in Treatment of Male Pattern Hair Loss. Phase 3, 703 men, completed. https://clinicaltrials.gov/study/NCT05910450

Clinical trial registration (NCT05914805). A Study to Evaluate the Efficacy and Safety of Clascoterone Solution in Treatment of Male Pattern Hair Loss (SCALP2). Phase 3, 762 men, completed. https://clinicaltrials.gov/study/NCT05914805

Clinical trial registration (NCT02279823). A Phase 2 Study to Evaluate the Safety and Efficacy of CB-03-01 Solution, a Comparator Solution and Vehicle Solution in Males With Androgenetic Alopecia. Phase 2, 95 men, completed. https://clinicaltrials.gov/study/NCT02279823

U.S. Food and Drug Administration. (2020). FDA approves new acne drug for the first time in nearly 40 years. https://www.fda.gov/news-events/press-announcements/fda-approves-new-acne-drug-first-time-nearly-40-years