Clascoterone (Winlevi / Breezula)

What clascoterone is

Clascoterone, chemically cortexolone 17α-propionate, is a steroid that acts in the skin as an antagonist of male hormones. The holder of the EU marketing authorization is the Italian company Cassiopea; the hair-loss trials are reported by Cosmo Pharmaceuticals. The 1 percent cream Winlevi is approved for acne and prescription-only; in the EU for acne in general in adults, and for facial acne in adolescents aged 12 and over.

For hereditary hair loss, the manufacturer is testing a 5 percent solution under the name Breezula. This would add to minoxidil and finasteride a mode of action that works only in the skin. What is rated here is the state of knowledge: good for acne, for hair so far only from press releases.

How it works

Dihydrotestosterone (DHT) stimulates the sebaceous glands via the androgen receptor and, in hereditary hair loss, shrinks the hair follicles. Clascoterone blocks this receptor where it is applied, without changing hormone production. This sets it apart from finasteride and dutasteride, which lower DHT production throughout the body. How exactly the cream works against acne, however, is described as unknown in the US prescribing information.

A small portion reaches the bloodstream. There, cortexolone is presumably formed; its levels after application to the face were mostly below or near the limit of detection. With extensive, maximal use, clascoterone can temporarily suppress the stress axis of hypothalamus, pituitary and adrenal glands, the HPA axis.

What the studies show

Hebert 2020: the pivotal acne trials

Two identical trials randomized 1,440 patients aged 9 and older with moderate to severe facial acne to clascoterone cream or vehicle cream, twice daily for 12 weeks. Treatment success was achieved by 18.4 and 20.3 percent versus 9.0 and 6.5 percent. Non-inflammatory lesions decreased by 19.4 instead of 13.0 and 10.8, inflammatory lesions by 19.3 and 20.0 instead of 15.5 and 12.6. Side effects were rare and mostly mild, most commonly mild redness.

Eichenfield 2024: up to one year

600 patients from the pivotal trials continued treatment open-label, 343 until the end. The proportion with clear or almost clear skin rose to 30.2 percent on the face after 12 months and to 31.7 percent on the trunk after 9 months. Without a control group and with many dropouts, this is an observation, not a comparison.

SCALP 1 and SCALP 2: hair loss

Two phase 3 trials with 703 and 762 men tested the 5 percent clascoterone solution against vehicle solution, six months double-blind, then six months single-blind. The primary endpoints were the number of terminal hairs in the target area and the participants’ own assessment. According to the press release of December 2025, hair count was significantly better in both trials, with relative improvements of 539 and 168 percent compared with the vehicle solution. On the participants’ own assessment, one trial was significant and the other showed a trend. The manufacturer did not give absolute hair counts.

The 12-month data

In April 2026, Cosmo reported: those who stayed on clascoterone for twelve months had a 2.39-fold greater improvement in hair count than participants who switched to vehicle solution after six months. Hair growth continued to increase from month 3 to month 12. Tolerability was comparable to the vehicle solution; no meaningful systemic hormonal side effects were observed.

Where the data stop

• Absolute numbers for hair. Relative improvements of 539 or 168 percent say little as long as it is not known from which baseline they were calculated. How many more hairs per square centimeter grow has not yet appeared in any publication.
• Independent review. The hair trials have been completed, but their results have so far appeared only as press releases. Cosmo has announced publication in a scientific journal.
• Larger area, higher concentration. The safety data on the HPA axis come from the 1 percent cream on the face. For the 5 percent solution on the scalp, there is only the manufacturer’s summary statement.
• Comparison with established treatments. There is no direct comparison with minoxidil or finasteride.

Status, approval and legal

The cream Winlevi has been approved in the US since 2020-08-26 for acne from age 12. In the EU, central approval followed on 2025-10-17: for acne in adults, and for facial acne in adolescents aged 12 to under 18. It is prescription-only and must not be used during pregnancy; contraception is required during treatment and for at least 10 days afterwards.

Clascoterone is not approved anywhere for hair loss. Cosmo is preparing the applications for the US and the EU; the company plans the US application for early 2027.

Safety

For the cream, the safety profile is well documented. Most common are redness, itching, scaling and dryness in 7 to 12 percent of those treated. Elevated potassium levels occurred in 5 percent, with vehicle cream in 4 percent. Under maximal use, individual patients showed temporary suppression of the HPA axis; the US prescribing information warns about this and names extensive and long-term use as risk factors, and children are considered more susceptible.

An analysis of the US adverse event reporting database covering the years after approval found, besides redness and dryness, rare but notable signals for HPA axis suppression, stretch marks and abnormal hair growth; over 70 percent of the reports concerned the first month of treatment. Reporting data show signals, not frequencies. For the 5 percent solution on the scalp, the manufacturer reports tolerability similar to the vehicle solution, without individual figures.

Sources

• Hebert A et al., JAMA Dermatol 2020 – clascoterone cream 1 % for acne, two phase 3 trials with 1,440 patients
• Eichenfield LF et al., J Drugs Dermatol 2024 – short- and long-term efficacy, extension up to 12 months
• Bhatia N et al., J Drugs Dermatol 2024 – HPA axis under maximal use, 69 patients
• Tao L et al., Ther Innov Regul Sci 2026 – adverse event reports on clascoterone in the US database FAERS
• FDA prescribing information Winlevi (clascoterone cream 1 %), DailyMed
• EMA – Winlevi, European public assessment report, approval 2025-10-17
• ClinicalTrials.gov NCT05910450 – SCALP 1, clascoterone solution 5 % for hair loss, 703 men
• ClinicalTrials.gov NCT05914805 – SCALP 2, clascoterone solution 5 % for hair loss, 762 men
• Cosmo Pharmaceuticals, press release 2025-12-03 – phase 3 results SCALP 1 and SCALP 2
• Cosmo Pharmaceuticals, press release 2026-04-15 – 12-month data from the phase 3 trials, US application early 2027