Breezula (Clascoterone) for Hair Loss - Does It Work?
The pharmaceuticals company Cosmo recently announced in December 2025 the top line results for its phase 3 clinical trials for Breezula at a 5% solution treatment for hair loss. While it has not yet published full results, the press release was very positive:
1,465 patients were randomized into the two identical-in-design clinical studies Scalp 1 (NCT05910450) and Scalp 2 (NCT05914805)
Both studies reached statistically significant endpoints in TAHC (Target-Area Hair Count), with one reaching 539% relative improvement to placebo and the second study reaching 168% relative improvement to placebo
So what is Breezula and why has it got attention?
Most men and many women who attend our clinic have androgenetic alopecia. The underlying process is well described. Dihydrotestosterone interacts with genetically sensitive hair follicles, gradually shortening the growth phase and producing finer, shorter hairs until visible thinning appears.
Current medical treatments tackle this problem in two main ways. Some aim to reduce the amount of dihydrotestosterone available. Finasteride is the clearest example. Others try to support hair growth despite ongoing hormonal pressure. Minoxidil sits firmly in this group.
Clascoterone approaches the problem from a slightly different angle. Rather than reducing hormone levels, it aims to block the androgen receptor within the scalp itself, preventing dihydrotestosterone from delivering its signal at the follicle. Instead of blocking the bodies production of DHT like Finasteride does, it attempts to stop DHT reaching the androgen receptor in the hair follicle by attaching Clascoterone to it instead.
This idea is not new in theory, but clascoterone is one of the first molecules to push it through modern clinical development.
Breezula is the registered brand name for the drug Clascoterone, which is already FDA approved in the US as a 1% topical cream for acne with the brand name Winlevi. This new treatment is focused on hair loss, and at a higher 5% concentration. This tells you two things. First, regulators accepted the general concept of topical androgen receptor blockade for skin disease. Second, developers gathered safety data that can inform scalp programmes, even though scalp dosing and concentrations are lower. The Journal of the American Academy of Dermatology sets out its mechanism, early studies, and safety themes.
When applied to the scalp, the intent is direct receptor binding within the hair follicle environment. If you can stop androgen signalling locally, you can slow miniaturisation. If you can slow miniaturisation early enough, you can preserve density. If you can preserve enough native hair, you reduce the need for surgery or you make a future hair transplant plan simpler.
How Clascoterone works in practical terms
When I explain this to patients, I try to keep it grounded.
Hair loss driven by hormones has two steps. First, testosterone is converted into dihydrotestosterone. Second, dihydrotestosterone binds to receptors in the follicle and triggers miniaturisation.
Finasteride acts earlier in the chain by reducing the conversion step. That is why it works well for many men, and also why side effects are discussed, as hormone levels change throughout the body.
Clascoterone acts later in the chain. It aims to sit on the androgen receptor within the skin and scalp, blocking dihydrotestosterone from binding and activating it. In theory, hormone levels elsewhere remain unchanged.
The challenge is delivery. The drug must reach the follicle in sufficient concentration, stay there long enough to matter, and do so consistently over years rather than months. The December 2025 trial announcement suggests that, at least in controlled conditions, this may be achievable.
Does Breezula regrow hair or just slow loss?
This is where expectations need careful management, and only on a "what we know so far" basis. Most anti-androgen treatments do not behave like miracle regrowth solutions. Their primary role is to slow or stop further loss. Regrowth, when it occurs, usually reflects thickening of miniaturised hairs rather than the creation of entirely new follicles.
The available information from clascoterone trials suggests improvements in target area hair counts compared with placebo, which indicates some degree of regrowth. What we do not yet have in full detail are the absolute numbers, the variation between individuals, and how those gains hold up over time.
In clinic, we see the same pattern repeatedly. Patients with early thinning often respond better to medicinal treatment. Those with long standing bald areas rarely do. For the latter group, hair transplants remain the only reliable way to restore visible density.
What evidence supports Breezula so far
Unlike finasteride or minoxidil, clascoterone does not yet have decades of published hair loss data behind it. What it does have is a growing body of dermatology literature explaining its mechanism, alongside registered clinical trials and now late stage topline results reporting statistically meaningful outcomes.
However... A claim of a 539% relative improvement or a 168% improvement means little when we don't have the figures of the control group. These are usually measured in how many extra hairs in a square centimeter were observed after a set time frame. Average human hairs grow at 60-100 per square cm, so if the control group only had a 1 hair improvement, and the Breezula improved on that by 500% then that's only a 5 hair improvement total, in an area that should have 60-100 hairs that would not give a noticable improvement in the real world. if the control group had a 10 hair improvement, then improving on that 500% gives an extra 50 hairs per square cm, which would be very noticable.
We also don't know if these results last long term, and we don't know if they are repeatable. So it's important to see the full results which wont be released until mid-2026.
The December 2025 announcement relates to phase III trials, which are designed to answer the question regulators care about most. Does this treatment produce a real effect in a real population when compared with placebo, and does it do so with an acceptable safety profile.
Topline data is not the end of the story. Full peer reviewed publications will need to confirm the size of benefit, the consistency of response, and the long term safety profile. Until then, any claim that Breezula will replace existing treatments is promising but premature.
Where Breezula stands in the UK
At present, clascoterone for hair loss is not a licensed treatment in the UK. The recent trial success places it closer to that goal, but approval, prescribing frameworks, and real world guidance take time.
This distinction matters. If you see clascoterone offered through unregulated channels, the issue is not just legality but quality. Concentration, formulation, and consistency are critical for a drug that relies on local delivery.
As clinicians, we work within systems that prioritise safety and follow up. That protects you in the long term.
How Breezula compares with finasteride
Finasteride remains the most effective medical option for many men with androgenetic alopecia. Its ability to reduce dihydrotestosterone has been demonstrated repeatedly, and its benefits in slowing hair loss are well established.
Breezula does not challenge that evidence. Instead, it offers a different strategy. For patients who cannot tolerate finasteride, or who are uncomfortable with systemic hormone manipulation, a topical receptor blocker may become an attractive option.
It is also possible that future treatment plans will combine approaches, using different mechanisms to maximise follicle protection. Whether this makes sense clinically will depend on further data.
How Breezula compares with minoxidil
Minoxidil works through growth stimulation rather than hormone control. Many patients see improvements in thickness or density with consistent use, especially in the crown.
The limitation is that minoxidil does not address the underlying hormonal trigger. That is why gains may plateau or reverse if androgen pressure remains high.
In that context, Breezula is not a replacement for minoxidil but a potential partner, targeting a different part of the problem.
Similar treatments pyrilutamide and RU58841
Clascoterone is not the only topical anti androgen discussed online.
Pyrilutamide (known as KX826 or Koshine 826) has progressed through formal clinical trials for hair loss and sits in a similar developmental category as an androgen receptor blocker, although full long term data remains limited, and their phase 3 trials did not show strong results.
RU58841, by contrast, is a research compound with older experimental evidence and no modern regulatory approval for patient use. Despite frequent online discussion, it lacks the safety and quality framework required for responsible clinical care. From a UK medical perspective, that distinction is crucial.
Where hair transplants fit into this picture
Medical treatment and surgery are often framed as competing options. In reality, they address different needs.
A hair transplant redistributes follicles to areas of visible loss. It does not stop ongoing miniaturisation elsewhere. Without medical support, transplanted hair can end up surrounded by thinning native hair, compromising the result.
Effective medical treatment protects both your existing hair and your surgical investment. If Breezula becomes an approved option, it may offer another way to achieve that protection for patients who cannot use finasteride, and gives us another complimentary weapon in our armoury to treat hair loss, but is unlikely to be a cure by itself.
How I explain Breezula to patients today
When patients ask about Breezula following the December 2025 news, my message is measured:
It represents a genuine scientific advance rather than marketing noise.
It targets the androgen pathway in a different way from existing treatments.
Early results are encouraging, but full published data is still needed.
It is not yet part of routine UK care.
If you already respond well to established treatments, there is no urgency to change. If you cannot use them, Breezula is worth watching closely.
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