The practical takeaway up front
Do not interpret “539% relative improvement” as “five times more hair on your head.” Treat it as a ratio attached to a specific measurement method, and assume it can look huge even when the mirror-visible change is modest. ([Cosmo Pharmaceuticals NV][1])
If you want a sober reading, you need three missing pieces that topline announcements usually do not show: the absolute hair-count change, the placebo absolute change, and how spread out the responses were across people. ([Cosmo Pharmaceuticals NV][1])
Everything below explains why.
What exactly was claimed in December 2025
On December 3, 2025, Cosmo Pharmaceuticals announced Phase 3 “topline” results for clascoterone 5% topical solution in male androgenetic alopecia, from two trials named SCALP 1 and SCALP 2. ([Cosmo Pharmaceuticals NV][1])
The press release says 1,465 men were enrolled across the two identically designed studies in the United States and Europe, and that both studies showed statistically significant improvement versus placebo vehicle in “Target-Area Hair Count.” ([Cosmo Pharmaceuticals NV][1])
The headline numbers were “5.39x (539%) relative improvement” in one trial and “1.68x (168%) relative improvement” in the other, versus placebo vehicle. ([Cosmo Pharmaceuticals NV][1])
That wording is real, but it is still not enough to know what the result means for a real person.
What “Target-Area Hair Count” is, and why trials use it
“Target-Area Hair Count” is a standardized way to count hairs in a small, fixed scalp area (often around one square centimeter) so the same patch can be compared over time. ([PubMed][2])
Many androgenetic alopecia trials use photographic or phototrichogram-based methods (basically, close-up standardized images) and often mark the location so the same area is measured again at later visits. ([thelancet.com][3])
In some studies, the endpoint is specifically “non-vellus” or “terminal” hairs, which are thicker hairs, and definitions like “terminal hair diameter at least 30 micrometers” appear in published trial methods. ([PMC][4])
This is not a perfect measurement, but it is one of the more objective tools available for hair-growth trials.
Why “relative improvement” can explode even when the real change is not dramatic
A large percentage does not automatically mean a large absolute difference.
Relative improvement is a ratio, so it depends heavily on what happened in the placebo group. If the placebo group barely changes, then dividing by a small number can create a very large percentage. ([Cosmo Pharmaceuticals NV][1])
There is also a second uncertainty: a press release rarely tells you the exact formula used to compute “relative improvement.” It could be a ratio of mean changes from baseline, or a ratio of treatment-versus-placebo differences, or another defined comparison. ([Cosmo Pharmaceuticals NV][1])
Without that formula and the raw absolute values, “539%” is not directly interpretable as a day-to-day outcome.
A simple numerical example to show the trap
This is only a math illustration, not the real trial data.
If placebo increased by 1 hair per square centimeter and the drug increased by 6 hairs per square centimeter, then the drug is 500% higher than placebo in a relative sense. But the absolute difference is 5 hairs per square centimeter, and whether that is noticeable depends on baseline density, hair caliber, lighting, styling, and where on the scalp it is measured.
This is why careful readers ask for absolute change first and percentage later.
Why “topline” is a warning label, not a guarantee
Topline results are usually designed to tell you that the study met its goals, not to let outsiders audit the magnitude.
Cosmo’s announcement uses words like “clinically meaningful,” but the press release format does not include full tables, confidence intervals, or responder analyses that would let you judge what “meaningful” means in practice. ([Cosmo Pharmaceuticals NV][1])
Independent reporting (for example, STAT) correctly frames these as company-released topline results from two late-stage trials, which is useful context, but it still is not the full dataset. ([STAT][5])
ClinicalTrials.gov confirms the study exists and provides high-level design information, but it does not replace a full results publication either. ([clinicaltrials.gov][6])
In other words, you can treat the signal as promising while still refusing to over-interpret it.
What details you should wait for before believing the headline
When full results arrive (publication, conference tables, or regulatory documents), three specifics will decide how impressive this really is.
First, the absolute change in Target-Area Hair Count from baseline in each arm at six months. Second, the placebo vehicle absolute change, because it determines how inflated the ratio can become. Third, the distribution: how many people had a meaningful gain, how many had a small gain, and how many did not respond.
These are standard expectations for interpreting hair-count endpoints, because Target-Area Hair Count is used across many trials and its interpretation depends on magnitude and variability, not only statistical significance. ([thelancet.com][3])
Until those pieces are visible, “539%” is a headline, not a practical forecast.
Sources
- Cosmo Pharmaceuticals press release (December 3, 2025): SCALP 1 and SCALP 2 topline results and the “5.39x (539%)” and “1.68x (168%)” claims. ([Cosmo Pharmaceuticals NV][1])
- Nasdaq press release repost (December 3, 2025): secondary copy of the same topline announcement. ([nasdaq.com][7])
- STAT News (December 3, 2025): independent reporting of the topline claims and framing. ([STAT][5])
- ClinicalTrials.gov (NCT05914805): confirms a Phase 3 clascoterone study in male pattern hair loss and basic purpose/design. ([clinicaltrials.gov][6])
- Examples of “Target-Area Hair Count” as a standard clinical endpoint and how it is measured/defined in published hair-loss trials and methods papers (phototrichogram, defined target areas, terminal-hair definitions). ([PMC][4])