Does creatine cause hair loss? The only direct trial found no change

Does creatine cause hair loss? In the first study built to answer that question directly, it did not. Researchers gave 45 resistance-trained men aged 18 to 40 either 5 grams of creatine monohydrate a day or 5 grams of maltodextrin, a bland carbohydrate powder used as a dummy treatment, and followed them for 12 weeks [1]. Thirty-eight finished.

Hair was measured, not asked about. The researchers used a trichogram, a test in which a small tuft of hair is pulled and the roots examined under a microscope, alongside a photographic scanning system that counts hair density, the number of follicular units (the small clusters the scalp grows hairs from) and total hair thickness [1].

None of those measures separated the creatine group from the placebo group [1].

The blood tests said the same thing. Total testosterone rose in both groups over the 12 weeks, and it rose more in the men on the dummy powder: about 216 nanograms per decilitre of blood against about 124 in the creatine group, a nanogram per decilitre being a measure of how much hormone sits in a set volume of blood [1]. Individual changes were spread widely enough in both groups that the gap between those averages is noise, not a creatine effect, which is how the researchers read it [1]. The free, unbound form of testosterone drifted down by the same small amount in each group [1].

DHT itself did not differ between the groups, and neither did the DHT-to-testosterone ratio [1]. Until this trial, nobody had looked at hair follicles in people taking creatine at all [1]. The concern rested on hormone theory, and it has stuck around long enough that an international panel of creatine researchers put "does creatine cause hair loss or baldness" among the twelve misconceptions it set out to examine in 2021, then came back with sixteen more questions about the supplement in a follow-up review [2] [3].

The idea that creatine thins hair is a chain of three links. Creatine raises DHT; higher DHT shrinks hair follicles; shrunken follicles grow thinner hair until they stop. If the first link fails, nothing downstream of it can happen.

The trial tested the first link, and it did not hold. DHT levels in the creatine group looked like DHT levels in the placebo group after 12 weeks [1]. The researchers also tracked the DHT-to-testosterone ratio, which is how much DHT is present relative to the testosterone it is made from, and that did not move either [1]. Both hormones drifted over the three months, but they drifted the same way in men taking nothing but flavourless carbohydrate [1].

So the argument never gets past its first step, at least in men like these. What the trial cannot tell you is what would happen to hair if DHT did rise, because in these men it did not [1].

This is one trial, and a small one. Thirty-eight men completed it, which is enough to catch a large effect on hair and not enough to rule out a small one - a study this size can miss a modest difference simply by chance, so "no difference found" is weaker evidence than "no difference exists" [1].

Twelve weeks is also short next to the thing being measured. Pattern hair loss develops over years, and a scalp that looks unchanged after three months has not been followed long enough to say much about a decade of daily use [1].

The evidence does not cover several groups of people:

• Women. Every participant was male [1].
• Men over 40, and men who do not lift weights. The trial recruited healthy resistance-trained men aged 18 to 40 [1].
• Anyone already losing hair. These were men with healthy hair follicles at the start, not men with diagnosed pattern baldness [1].
• Anyone taking more than the 5 grams a day the trial tested, or using the higher loading doses some people start with [1].

None of it applies to alopecia areata either, a separate autoimmune condition in which the immune system attacks hair follicles and hair falls out in patches. That one is treated with prescription drugs and has its own trial evidence [4].

A 26-year-old man starts creatine, and six weeks later notices more hairs than usual in the shower drain. The trial cannot tell him whether those two things are connected, because it measured group averages and not individuals, and hair sheds for plenty of reasons that have nothing to do with a supplement tub. What it can tell him is that when researchers measured density, follicle counts and thickness in men his age on the same daily amount, the creatine group's scalps came out looking like the placebo group's [1]. Hair loss gets diagnosed by a doctor who can look at the scalp, not by working backwards from what someone started taking.