Clascoterone for Hair Loss: Topical Anti-Androgen

For decades, finasteride and dutasteride have been the only meaningful anti-androgen options for androgenetic alopecia (AGA). Both work by reducing DHT production systemically, which is effective but comes with a side effect profile that makes some patients hesitant. Clascoterone represents a different approach: it blocks DHT at the androgen receptor in the skin itself, without lowering DHT levels in the bloodstream. The FDA approved it for acne in 2020 under the brand name Winlevi, and the hair-loss programme has since run through Phase 3 among dermatologists and patients. This is not a fringe compound. It is a clinically validated molecule with a clear mechanism, and the AGA data so far is encouraging.

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What clascoterone is and how it works

Clascoterone (cortexolone 17a-propionate) is a topical androgen receptor inhibitor originally developed by Cassiopea SpA, since absorbed into Cosmo Pharmaceuticals, which now runs the hair-loss programme. It competes directly with dihydrotestosterone (DHT) for binding at the androgen receptor. When applied to the skin, it occupies the receptor site and prevents DHT from activating the downstream signaling that shrinks hair follicles in AGA.

The critical distinction from finasteride and dutasteride: those drugs inhibit 5-alpha reductase, the enzyme that converts testosterone to DHT. They lower DHT systemically, throughout the entire body, by 60-70% (finasteride) or over 90% (dutasteride). Clascoterone does not reduce DHT production at all. It simply blocks DHT from doing its work at the specific receptor where it is applied. Systemic DHT levels remain unchanged, which is why the side effect profile differs substantially.

The acne approval and what it signals for AGA

In August 2020, the FDA approved clascoterone 1% cream (Winlevi) for the topical treatment of acne vulgaris in patients 12 years and older. This made it the first new mechanism of action approved for acne in nearly 40 years. The approval was based on two Phase III trials with over 1,400 patients that showed statistically significant reductions in inflammatory and non-inflammatory acne lesions compared to vehicle (placebo).

The acne approval matters for AGA because it establishes a safety track record. The FDA reviewed systemic absorption data and found that clascoterone applied topically did not meaningfully alter serum hormone levels. Testosterone, DHT, cortisol, and ACTH remained within normal ranges in clinical trial participants. This safety profile is the foundation for the AGA development program, where the drug is applied to the scalp at higher concentrations.

Phase II trial data for androgenetic alopecia

Cassiopea conducted a Phase II dose-ranging study testing clascoterone solution at concentrations of 1%, 2.5%, 5%, and 7.5% applied twice daily to the scalps of men with mild to moderate AGA. The primary endpoint was change in target area hair count (TAHC) at 12 months, measured by standardized macrophotography.

The 7.5% concentration produced the strongest results: a statistically significant increase in hair count compared to placebo at 12 months. The company reported that the improvement was clinically meaningful, though the exact magnitude of the hair count increase was described in relative terms rather than absolute numbers in publicly available data. The lower concentrations (1% and 2.5%) showed trends toward improvement but did not reach statistical significance, while the 5% concentration showed intermediate results.

Importantly, the study measured adverse events carefully. No clinically significant changes in serum testosterone, DHT, or other hormones were detected in any treatment group. The most common side effects were local: application site reactions including erythema, dryness, and pruritus, all mild and reversible. No sexual side effects were reported at rates above placebo.

What the Phase 3 programme found

The Phase 3 programme moved to a 5% solution, not the 7.5% that topped the Phase 2 dose range. It ran as two identically designed trials, SCALP 1 (NCT05910450, 703 men) and SCALP 2 (NCT05914805, 762 men), across 51 centres in the United States and Europe. Cosmo reported topline results on 3 December 2025: both trials hit statistical significance on target area hair count against vehicle, one with a 539% relative improvement and the other with 168%, and adverse events were comparable to vehicle.

Read those two percentages carefully. A relative improvement against a vehicle arm that itself lost ground is not the same as a hair count gain, and the gap between 539% and 168% in two trials of the same design is a reminder of how much the denominator moves. The company has not published absolute hair counts per arm.

On 15 April 2026 Cosmo reported the 12-month extension. Responders from the first six months were re-randomised either to stay on clascoterone or to switch to vehicle. Those who stayed on it kept gaining hair through month 12; those who switched lost part of what they had gained. That is the finding with the most practical weight in the whole programme, and it is the same pattern finasteride and minoxidil show: the effect is maintenance, not a cure, and it is contingent on continuing.

If you do end up on it, that re-randomisation result is also the argument for photographing consistently from the start. A drug whose benefit unwinds when you stop is one where a gap in your routine shows up months later, and matched monthly photos are the only way to see it happening rather than infer it afterwards.

How clascoterone compares to finasteride

Finasteride 1 mg daily reduces scalp DHT by approximately 60-70% and increases hair count by an average of about 10% over 12-24 months in clinical trials (Kaufman et al., 1998, Journal of the American Academy of Dermatology). It is the gold standard oral anti-androgen for AGA. Its drawback: roughly 2-4% of users report sexual side effects including decreased libido, erectile dysfunction, or reduced ejaculate volume. A small subset reports persistent symptoms after discontinuation, though the prevalence and causality of "post-finasteride syndrome" remains debated.

Clascoterone sidesteps this concern entirely by acting locally. Because systemic DHT is not reduced, the theoretical risk of systemic anti-androgen side effects drops significantly. The trade-off is that Phase II data, while positive, has not yet been compared head-to-head with finasteride in a randomized trial. We do not know whether clascoterone produces equivalent, better, or slightly inferior hair count improvements compared to oral finasteride. The Phase 3 programme used a vehicle control, not finasteride, so it did not settle this. For a broader look at topical anti-androgen options, see our guide on topical vs oral finasteride.

Connection to pyrilutamide and other topical anti-androgens

Clascoterone is not the only topical anti-androgen in development. Pyrilutamide (KX-826), developed by Kintor Pharmaceutical, is another androgen receptor antagonist being tested for AGA. Both drugs block DHT at the receptor level rather than reducing its production. They differ in molecular structure, binding affinity, and stage of clinical development. For details on pyrilutamide specifically, see our pyrilutamide research overview.

The broader trend is clear: the field is moving toward topical, receptor-level treatments that avoid systemic hormone manipulation. Clascoterone has the advantage of an existing FDA approval (for acne) and a known safety profile. Pyrilutamide is earlier in development but has shown promising Phase II data from trials conducted primarily in China. Both represent a shift away from the 5-alpha reductase inhibitor paradigm that has dominated AGA treatment since finasteride's approval in 1997.

Potential for women with androgenetic alopecia

One of the most significant potential advantages of clascoterone is its applicability to women. Oral finasteride is contraindicated in women of childbearing potential because systemic DHT reduction can cause birth defects in male fetuses. Dutasteride carries the same risk. This leaves women with AGA relying primarily on minoxidil and spironolactone (an off-label anti-androgen with its own side effect considerations).

Because clascoterone does not lower systemic DHT, it could offer women a targeted anti-androgen option without the teratogenicity risk associated with oral 5-alpha reductase inhibitors. Clinical trials specifically evaluating clascoterone for female pattern hair loss have not yet reported results, but the pharmacological rationale is strong. Dermatologists following the AGA pipeline consider this one of the most promising applications of the drug.

Current availability and off-label use

Clascoterone is still not approved for hair loss, in the United States or anywhere else. The only approved indication is acne vulgaris (Winlevi 1% cream). Using Winlevi for AGA would be off-label, and the 1% concentration is well below the 5% solution the hair-loss trials used. Some compounding pharmacies may prepare higher-concentration clascoterone formulations, but quality, stability, and bioavailability of compounded preparations vary.

The gap between "trials succeeded" and "you can get a prescription" is the whole story here. Cosmo said in April 2026 that NDA and MAA preparations were underway with a US filing planned for early 2027. A filing is not an approval, and review adds time after that. Until then, patients interested in clascoterone for hair loss should discuss the current evidence with a dermatologist who stays current on the AGA pipeline.

What to track if you start clascoterone off-label

If your dermatologist prescribes clascoterone for AGA, structured tracking is essential because you are using a drug without established AGA-specific dosing guidelines. The Phase II trial used a 12-month endpoint, so you should plan to track for at least that long before drawing conclusions. Use the anti-androgen treatment tracker to build your monitoring protocol.

• Baseline photos: Capture front hairline, both temples, crown, and top-down shots before the first application. Same lighting, same angles, same distance every time.
• Monthly photo comparisons: Hair grows at roughly 1.25 cm per month. Monthly intervals are the minimum frequency to detect density changes.
• Side effect log: Record any scalp irritation, redness, dryness, or itching at the application site. These were the most common adverse events in trials.
• Concurrent treatments: Log every other active treatment (minoxidil, ketoconazole shampoo, anything else) used alongside clascoterone. Combination effects cannot be separated without documentation.
• 3-month and 6-month checkpoints: Compare photos against baseline at these intervals. Visible improvement before month 6 is unlikely based on the biology of hair cycling.

Read more treatment tracking strategies on our blog, and bring your photo timeline to every follow-up appointment. Objective visual data gives your dermatologist better information than your subjective impression of whether things are improving.

Frequently asked questions

Is clascoterone approved for hair loss?

No. Clascoterone (Winlevi) is FDA-approved only for acne vulgaris. The Phase 3 hair-loss trials reported positive results in December 2025 and April 2026, but the drug has not been filed for approval in the AGA indication yet, let alone approved. Any use for hair loss at this point is off-label.

How does clascoterone differ from finasteride?

Finasteride lowers DHT production systemically by inhibiting the 5-alpha reductase enzyme. Clascoterone blocks DHT at the androgen receptor in the skin without reducing circulating DHT levels. This local mechanism avoids the systemic hormonal changes that cause finasteride's reported sexual side effects.

Can women use clascoterone for hair loss?

Clascoterone has strong theoretical potential for female AGA because it does not reduce systemic DHT and avoids the teratogenicity risk of oral finasteride and dutasteride. Clinical trials specifically for female pattern hair loss have not yet reported results, but dermatologists view this as one of the drug's most promising future applications.

When will clascoterone be available for AGA?

The trials are done and positive. What remains is regulatory. Cosmo said in April 2026 that a US filing was planned for early 2027, with a European submission in parallel. Standard FDA review of a new indication runs about a year from filing, so the earliest plausible availability is 2028, and regulatory timelines slip.

The bottom line on clascoterone for hair loss

Clascoterone is not yet an AGA treatment you can pick up at a pharmacy. But it is the most advanced topical androgen receptor inhibitor in development, backed by an FDA safety record from the acne indication and now by two positive Phase 3 trials with 12-month data. For patients who want anti-androgen protection without systemic DHT reduction, and for women who currently have no approved anti-androgen option for hair loss, it represents a genuine step forward. The practical move while the filing works its way through is to build a photo baseline now, so that if you do start clascoterone in 2028 you already have two years of clean comparison data rather than a memory of what your hairline used to look like.