Clascoterone Passes Phase 3: The First New Hair Loss Mechanism in 30 Years

The last time a genuinely new approach to hair loss reached patients was 1997, when minoxidil received FDA approval in topical form, followed by finasteride in 1998. Both drugs have defined the field ever since, but they share a well-known ceiling: minoxidil works by improving blood flow without addressing the underlying hormonal cause, while finasteride lowers DHT (dihydrotestosterone, the androgen that shrinks hair follicles) system-wide, which brings with it a risk of whole-body hormonal side effects.

The Phase 3 results Cosmo Pharmaceuticals announced in April 2026 represent the first serious departure from that paradigm in three decades.

What clascoterone is

Clascoterone is already an FDA-approved ingredient. At 1% concentration, it’s been sold as Winlevi for acne treatment since 2020. Applied to skin, it binds to androgen receptors in sebaceous glands and blocks DHT signaling, reducing the hormonal stimulus that drives excess oil production.

For hair loss, researchers use a higher 5% concentration under the development name Breezula.

The mechanism here differs from finasteride in a fundamental way. Finasteride prevents DHT from being produced, reducing levels throughout the bloodstream. Clascoterone doesn’t suppress DHT production at all. Instead, it occupies the androgen receptors in the hair follicle itself, blocking DHT from binding even when circulating levels remain unchanged. Because the active compound stays local to the scalp rather than entering the bloodstream in meaningful amounts, it doesn’t alter systemic hormone levels.

What the Phase 3 trials found

Cosmo Pharmaceuticals ran two concurrent trials: SCALP 1 and SCALP 2. Both were multicenter, randomized, double-blind, and vehicle-controlled (vehicle meaning a formulation identical in base composition but without the active compound). A total of 1,465 men participated, receiving six months of double-blind treatment followed by a six-month single-blind extension period.

The primary endpoint was change in target-area hair count.

• SCALP 1: The clascoterone 5% group showed 5.39 times more hair count improvement than placebo (a 539% relative improvement).
• SCALP 2: The clascoterone group showed 1.68 times more improvement than placebo (168% relative).

The two trials produced results of different magnitudes, but both met statistical significance. Across all 1,465 patients, the safety profile of clascoterone 5% was comparable to vehicle. No hormone-related adverse events, including the sexual dysfunction and mood changes associated with finasteride in a subset of users, were reported.

How it compares to current options

Three approaches currently dominate androgenetic alopecia treatment:

Minoxidil: Dilates blood vessels to improve circulation around hair follicles. Has no direct effect on androgen signaling, which means it addresses symptoms without targeting the underlying cause. Available as a topical solution or oral tablet.

Finasteride: Inhibits 5-alpha reductase (the enzyme that converts testosterone into DHT), which reduces DHT levels throughout the body. Effective for many men but carries documented risks of sexual side effects, and is contraindicated during pregnancy, making it inaccessible for most women.

Clascoterone: Blocks androgen receptors at the follicle level without suppressing systemic DHT. The hormonal environment elsewhere in the body remains unchanged. Because systemic exposure is minimal, the side effect profile in Phase 3 looked comparable to placebo.

The significance of this distinction goes beyond pharmacology. One of the most consistent barriers to treatment in androgenetic alopecia is patient reluctance driven by side effect concerns, particularly around finasteride. A topical anti-androgen that works locally changes the risk calculus for that group.

The path to approval

Cosmo Pharmaceuticals expects to complete 12-month safety follow-up data in spring 2026 and file for approval with the FDA and EMA simultaneously. Following the announcement, Cosmo’s stock rose 40% in a single session.

If approved, Breezula would mark roughly 30 years since a treatment with a truly distinct mechanism reached patients with androgenetic alopecia. It could be used on its own or alongside existing treatments, expanding the combination options for people who haven’t responded adequately to minoxidil or finasteride alone.

Separate trials targeting female androgenetic alopecia are in planning stages. The follicle-local mechanism, which avoids disrupting systemic hormone levels, may prove especially relevant for women, for whom systemic anti-androgens carry more complex risk profiles. Current Phase 3 data covers men only, so any extrapolation to female hair loss will depend on dedicated trial results.

Frequently Asked Questions

How is clascoterone different from existing hair loss treatments?

Finasteride suppresses DHT production throughout the body. Minoxidil increases blood flow to the scalp. Clascoterone is applied topically and blocks androgen receptors directly at the hair follicle. Because systemic absorption is minimal, the risk of hormone-related side effects is significantly lower.

Can women use it for hair loss?

The current Phase 3 trials enrolled men only. Separate trials for female androgenetic alopecia are planned. Because clascoterone works locally at the follicle without affecting systemic hormone levels, it may be particularly well-suited for women.

When will it be available?

Cosmo Pharmaceuticals plans to complete 12-month safety follow-up data in spring 2026, then submit simultaneously to the FDA and EMA for approval. If cleared, Breezula would be the first hair loss treatment with an entirely new mechanism in roughly 30 years.