There has been a lot of attention around a new 2025 randomized controlled trial that looked directly at creatine supplementation and hair loss. Media outlets, fitness influencers, and Reddit threads everywhere have largely boiled the study down to a simple takeaway:

“Creatine doesn’t cause hair loss.”

The study does offer valuable data. It’s the first trial to pair blood androgen measurements with direct, dermatologist-evaluated hair metrics. And importantly, it didn’t replicate the results of the 2009 rugby study that reported a sharp spike in DHT after creatine loading.

But after reading the paper, and hearing from the authors, there’s one key methodological detail that is being overlooked, and it matters a lot for how broadly the results can be applied.

Before getting to that, let’s briefly cover what the study actually did show.

What the Study Found (and Why It Actually Is Good Evidence for Some People)

Forty-five resistance-trained men were randomized to 5 g/day creatine or placebo for 12 weeks. They kept their normal diets and training, and underwent:

  • Blood tests (total T, free T, DHT)
  • Trichogram tests
  • FotoFinder hair density/thickness imaging

The results were straightforward:

Hormones

  • Total testosterone increased over 12 weeks (in both creatine and placebo).
  • Free testosterone decreased (also in both groups).
  • DHT did not change significantly.
  • DHT:T ratio decreased over time.
  • DHT:free T ratio increased, but only because free T dropped — not because DHT rose.

Each of these hormone shifts were similar in the creatine and placebo groups.

Hair metrics

Across all measured hair outcomes:

  • Hair density
  • Hair count
  • Anagen %
  • Telogen %
  • Terminal vs vellus proportions
  • Cumulative hair shaft thickness
  • Follicular units

…the study found no change over 12 weeks and no significant difference between creatine and placebo.

The authors also ran rank-based analyses, outlier sensitivity checks, and multiple statistical corrections, and again found no significant changes.

But here’s the part that most sources haven’t talked about:

Who Was Actually Allowed to Participate in This Study?

The Key Detail: The Study Excluded Participants with Any Signs of AGA — Even Mild Miniaturization

The paper lists this exclusion criterion:

“Dermatological or systemic conditions known to influence hair loss, such as alopecia areata or thyroid disorders.”

It’s ambiguous whether this includes androgenetic alopecia (AGA) itself, so I reached out to the study authors for clarification.

They responded that:

Every participant was “examined in person by a dermatologist before entering the study, and any signs of androgenetic alopecia (even early-stage or mild miniaturization) were grounds for exclusion.”

That means:

  • Not just men diagnosed with AGA were excluded
  • But men with any degree of miniaturization
  • Including subtle signs many men already have in their 20s

In other words, the study population consisted only of men with no clinical or even early signs of AGA.

Why This Screening Choice Limits the Study’s External Validity

1. AGA requires genetic susceptibility

Some men simply do not have the genetic predisposition for AGA. If you remove everyone with that susceptibility, you remove the exact group that is most likely to experience hair loss.

2. The study likely excluded most men with genetic predisposition to AGA

While many of the study participants were young (ranging from 18-40), the exclusion criteria likely would have caught most men with a predisposition to aggressive AGA.

Even in young men who don’t yet have visible AGA, miniaturization is often detectable to dermatologists.

Excluding all participants with miniaturization detectable by a dermatologist means there were likely very few or even no men genetically predisposed to significant AGA, particularly given the small sample of 19 men in each of the treatment and control groups.

3. Blood tests alone don’t rule out hair loss driven by factors other than DHT

The study does suggest that creatine doesn’t significantly raise DHT, in contrast to the famous 2009 rugby-player study. But it doesn’t answer whether creatine might accelerate hair loss in men with AGA through some other mechanism.

So the study answers one question clearly — and another not at all

The study provides strong evidence that creatine doesn’t cause hair loss or raise DHT in men who do not have preexisting AGA/miniaturization, at least over a 12 week period.

But it doesn’t address whether creatine accelerates AGA in men with existing AGA, because those men were explicitly excluded. Similarly, men predisposed to aggressive AGA were likely excluded by the study’s criteria.

So What Should You Do if You’re Worried About Hair Loss?

If you have no signs of AGA and no strong family history:
Creatine is unlikely to cause hair loss.

If you already have AGA or are predisposed:
The study simply doesn’t answer that question. Creatine is probably a minor factor at most, but personal monitoring matters more than online anecdotes.

Regardless of predisposition:

  • If you’re worried, monitor your average shedding over a few weeks before starting creatine, and monitor whether and how it changes after you start
  • If shedding increases noticeably, you can stop
  • If you’re concerned about hair loss in general, FDA-approved treatments matter far more than tweaking creatine intake

Conclusion

The new study is a high-quality trial and strongly suggests that creatine:

  • Does not raise DHT, and,
  • Does not worsen hair outcomes in men without AGA

But because the researchers screened out anyone with even mild signs of androgenetic alopecia, the results tell us much less about creatine’s potential effects men who are genetically predisposed to male pattern baldness.