Clascoterone 5% (Breezula): What Do the New Phase 3 Results Really Tell Us?

Male pattern hair loss (androgenetic alopecia) is a chronic condition that affects millions of men worldwide, with a clear impact on self-confidence and quality of life. For decades, evidence-based medical treatments have largely revolved around two pillars: topical minoxidil and oral 5-alpha reductase inhibitors such as finasteride and dutasteride. Many patients and physicians have been waiting for a genuinely new mechanism to enter the field.

In late 2025, Ireland-based Cosmo Pharmaceuticals announced six‑month “topline” Phase 3 results from two large clinical trials (SCALP‑1 and SCALP‑2) of a clascoterone 5% topical solution for male pattern hair loss. The news has been described as one of the most significant new drug developments in this area in roughly 30 years.

However, it is crucial to underline that this product is still an investigational drug candidate. It has no marketing authorisation for male pattern hair loss in any country yet. What we have so far are summary data; detailed scientific publications, long‑term safety outcomes and regulatory decisions are still pending. This article aims to summarise the current information in a medically cautious and educational way.

What Is Clascoterone (Breezula)?

Clascoterone, also known by its scientific name cortexolone 17α‑propionate (CB‑03‑01), is a steroidal topical androgen receptor (AR) antagonist. In simple terms, rather than reducing DHT (dihydrotestosterone) production systemically, it aims to block DHT locally at the hair follicle receptor level in the scalp.

• The same molecule in a 1% cream formulation has FDA approval in the United States under the brand name Winlevi® for the treatment of acne.
• The 5% topical solution being studied for hair loss has been referred to under the development name Breezula® and is currently in Phase 3 clinical development for male androgenetic alopecia.

After topical application, the drug is rapidly converted in the skin into a more inactive metabolite (cortexolone). The aim is to keep systemic exposure low and concentrate pharmacological activity locally in the scalp, thereby theoretically reducing the risk of systemic side effects.

Current Standard Treatments for Male Pattern Hair Loss

In everyday clinical practice, scientifically supported treatments for male pattern hair loss can be grouped into three main categories:

1. Topical Minoxidil

• Supports the vascular bed around hair follicles, prolongs the anagen (growth) phase, and increases certain growth factors.
• Does not directly target the DHT pathway; its primary role is to support hair calibre and density.

2. Oral 5‑Alpha Reductase Inhibitors (Finasteride, Dutasteride)

• Reduce systemic conversion of testosterone to DHT.
• Effective for many men, but there are ongoing concerns and discussions about potential systemic hormonal side effects in some individuals.

3. Hair Transplantation and Surgical Solutions

• In advanced stages of hair loss (Norwood 5–7), medical therapy alone is often insufficient to restore density.
• In these cases, redistributing follicles from the donor area to bald or thinning regions via hair transplantation can provide a permanent and natural‑looking solution. For a detailed overview, see our hair transplant guide.

If clascoterone 5% eventually receives approval for this indication, it would add a new component to this landscape: the first widely available topical anti‑androgen that works locally at the receptor level, instead of altering DHT production systemically.

How Were the SCALP‑1 and SCALP‑2 Phase 3 Studies Designed?

According to the sponsor’s announcements, the Phase 3 programme for clascoterone 5% is among the largest topical therapy trials ever conducted in male pattern hair loss:

• Approximately 1,465 male participants across centres in the United States and Europe
• Treatment over 6 months, applied twice daily
• Clascoterone 5% solution vs. vehicle/placebo solution (similar formulation without active ingredient)
• Randomised, double‑blind, vehicle‑controlled design
• Planned 12‑month total observation including extended safety follow‑up beyond the 6‑month efficacy read‑out

Primary endpoints included:

1. Target Area Hair Count (TAHC)
   Change in terminal hair count (hairs/cm²) within a defined small target area of the scalp.
2. Patient‑reported outcomes (PRO)
   Questionnaires assessing participants’ own perception of hair appearance and changes in hair density.

The combination of TAHC and PRO aims to capture both objective hair count changes and how meaningful these changes feel to the patient when looking in the mirror.

What Do the Reported Phase 3 Results Show?

Based on the six‑month topline data released by Cosmo Pharmaceuticals, the following key findings were reported:

• Both Phase 3 studies, SCALP‑1 and SCALP‑2, met their primary TAHC endpoints with statistically significant improvements over vehicle.
• In the clascoterone 5% arms at Month 6, the company reported:
  • In one trial, approximately a 539% relative improvement in TAHC versus placebo,
  • In the other, around a 168% relative improvement versus placebo.
• For patient‑reported outcomes:
  • One Phase 3 trial showed statistically significant improvement in PRO scores,
  • The other showed a positive but borderline trend; pooled analysis of both studies demonstrated a statistically significant PRO benefit.

It is important to emphasise that these percentages represent relative changes compared with the placebo arm. They should not be interpreted as “five times more hair” in a literal, everyday sense. The absolute hair‑count gains (hairs/cm²) and photographic examples will be better understood once full scientific manuscripts and detailed data sets are published.

Safety Profile: So Far, Similar to Placebo

From the Phase 3 topline data and prior experience with clascoterone in acne, the early safety picture can be summarised as follows:

• Treatment‑emergent adverse events (TEAEs) were reported at similar rates in the active and vehicle groups.
• The most frequent events were local skin reactions expected with topical treatments, such as mild erythema, itching or irritation at the application site.
• No clear safety signal of systemic hormonal side effects has been highlighted in the topline summaries so far, which supports the idea that the drug’s primary activity is local.

That said, long‑term safety over years, in large and diverse real‑world populations, can only be clarified after approval, through pharmacovigilance programmes and post‑marketing experience.

Clinical Interpretation: How Meaningful Are These Results?

In summary, the current data suggest that clascoterone 5%:

• Represents the first serious candidate in the class of topical, locally acting anti‑androgens for male pattern hair loss.
• Demonstrated statistically significant improvements in target area hair counts over vehicle in its Phase 3 trials after only six months of treatment.
• Appears to have a favourable and well‑tolerated safety profile in the information released so far, with adverse event rates close to placebo and mainly mild local reactions.

However, several key questions remain:

• What is the magnitude of effect in absolute terms (hairs/cm²)?
• How does the drug compare directly with established therapies such as oral finasteride/dutasteride or topical minoxidil?
• What does the benefit–risk ratio look like in different patient profiles and over longer periods?

At this time, there are no head‑to‑head studies directly comparing clascoterone with existing standards. Independent experts generally describe the results as “promising but not miraculous” and suggest that the treatment’s effect will likely sit in the moderate‑to‑strong range rather than representing a complete paradigm shift.

Regulatory Status: When Could It Become Available?

According to the sponsor’s communications, the 12‑month safety follow‑up for the Phase 3 programme is planned to be completed and then integrated into a full data package. The company has indicated its intention to file for approval with both the U.S. FDA and the European Medicines Agency (EMA) after the data are fully assembled.

As of now:

• Clascoterone 5% topical solution has not been approved for male pattern hair loss in any country.
• There is no authorised, pharmacy‑dispensed AGA formulation available in Turkey or elsewhere.
• The timeline and outcome of regulatory review depend entirely on the decisions of the respective authorities, which may request additional analyses or data.

In other words, the product discussed in this article remains a Phase 3 investigational drug candidate and is not part of routine clinical practice for androgenetic alopecia today.

If Approved, Who Might Be a Good Candidate?

With all necessary disclaimers, and based purely on theoretical interpretation of current data, clascoterone 5% could, if approved, be particularly relevant for:

• Men with mild to moderate androgenetic alopecia,
• Those primarily concerned with preserving and improving density in the mid‑scalp and vertex,
• Patients who are reluctant to use systemic 5‑alpha reductase inhibitors because of concern about hormonal side effects,
• Men whose hair loss is not yet very advanced, with robust donor areas and limited completely bald, shiny zones.

In more advanced cases, clascoterone—like minoxidil or finasteride—would not be able to “create” hair follicles where none exist. It is unlikely to fully cover large, shiny bald areas on its own. In such patterns, hair transplantation remains the primary surgical option, while medical therapies focus on protecting and improving the quality of existing hair. For a broader discussion of how different methods fit together, see our article on hair transplant methods.

Hair of Istanbul’s Approach: Combining Medical Therapy and Hair Transplantation

At Hair of Istanbul, we evaluate every new treatment candidate through the combined lens of:

• Scientific data quality and maturity,
• Safety profile and long‑term unknowns,
• Realistic patient expectations.

Clascoterone 5% topical solution is, on paper, an exciting new candidate for male pattern hair loss. Nonetheless, as of today it remains an experimental molecule and is not a standard treatment in any centre for this indication.

Our general philosophy is to:

• Use approved and evidence‑based treatments (minoxidil, finasteride/dutasteride, and other supportive protocols) within a personalised medical plan,
• Introduce hair transplantation when indicated, positioning surgery and medical therapy as complementary rather than competing tools,
• Monitor emerging treatments like clascoterone closely and integrate them into practice only once they are formally approved and supported by robust real‑world safety and efficacy data.

Every patient’s pattern of hair loss, donor capacity, and general medical status is unique. For this reason, both medical and surgical options should always be planned after an individual consultation. If you wish to explore surgical options in more detail, you can also review our guide on hair transplants for men.

This article is for educational purposes only and does not replace medical consultation. Diagnosis and treatment decisions must always be made by a qualified physician.

External reference: The Phase 3 topline data summarised above are based on the official announcement released by Cosmo Pharmaceuticals. You can read their corporate summary here: Cosmo Pharmaceuticals Phase III topline results.