Hair Loss

Research on biotin for hair growth is highly limited. Although biotin has been included in multicomponent supplements for hair loss,^[18] no clinical trials have looked at the effect of biotin alone on hair growth or hair loss. Biotin deficiency often results in hair loss, but biotin deficiency is extremely rare, meaning it can’t be assumed that biotin will improve hair health in the vast majority of people.^[19] Still, one study found that low biotin levels (<100 ng/L) were common among women with hair loss due to telogen effluvium.^[20] Unfortunately, until clinical trials are performed, it is premature to say whether supplementation with biotin can promote hair growth.

It is sometimes believed that male-pattern baldness is inherited only from the mother’s side and not from the father's side. In reality, existing research shows quite clearly that genetic susceptibility to male-pattern baldness is determined by genes inherited from one’s mother and father.^[12][13] It’s possible this myth of maternal-specific inheritance of hair loss comes from the fact that the X chromosome (which, for biological males, comes entirely from the mother’s side) carries the androgen receptor (AR) gene and mutations to this gene are known to have a major impact on the risk of male-pattern baldness. However, genes carried on autosomes (i.e., from both parents) seem to have a larger cumulative effect on hair loss than those from the X chromosome.

While higher testosterone levels help explain why baldness is common among men and uncommon among women, this is an incomplete picture of the underlying physiology. Rather, it is a testosterone metabolite called dihydrotestosterone (DHT) that contributes to male-pattern hair loss and mediates the discrepancy in baldness rates between sexes.

One of the most effective treatments for male-pattern hair loss is finasteride, a drug that inhibits the conversion of testosterone into DHT.^[14] In fact, by blocking the metabolism of testosterone in this way, finasteride can increase testosterone levels,^[15][16] further emphasizing the limitations of testosterone as a marker of hair loss risk.

Having very low levels of circulating testosterone can reduce the amount of DHT synthesized, explaining why women (and men with very low testosterone) seem more resistant to baldness.^[17] However, it is not necessarily the case that alterations to testosterone levels within normal levels will automatically translate into changes in DHT levels or, more importantly, risk of hair loss.

Although plausible, it seems unlikely that supplementing with creatine causes hair loss.

By binding to androgen receptors in susceptible hair follicles, dihydrotestosterone (DHT; a testosterone metabolite) can cause hair follicles to shrink, ultimately leading to hair loss.^[21][22] That said, whether a given hair is more or less likely to fall depends on its location (in male-pattern hair loss, the crown and hairline thin first) and the person’s genetic predisposition to hair loss.^[23][24]

A proposed mechanism behind creatine’s effect on testosterone

The idea that supplemental creatine could be linked to hair loss largely originates from the findings of a 2009 randomized controlled trial.^[25] In this trial, college-aged male rugby players who took creatine monohydrate for 3 weeks experienced a 41% increase in their blood levels of DHT. The baseline DHT concentration was 0.98 nmol/L and the concentration after 3 weeks was 1.26 nmol/L, with both values being well within the normal range.

To date, this has been the only trial testing creatine’s effects on DHT. However, 12 other trials have tested creatine’s effects on testosterone. Of these, only two trials (lasting 6 and 7 days) have reported increases in testosterone levels,^{[26] [27]} while the remaining 10 trials (which ranged in duration from 6 days to 12 weeks) found no effect.^{[28][29][30][25][31][32][33][34][35][36]} Importantly, 5 of these trials specifically tested creatine’s effects on free testosterone, the form of testosterone that gets converted to DHT, and found no significant increases.^{[28][31][33][29][35]}

Lastly, and perhaps most importantly, the effect of supplemental creatine on hair loss hasn’t been directly studied, so all we can do is make educated guesses.

To sum up: (i) Only one trial has reported an increase in DHT levels with supplemental creatine; (ii) although DHT levels increased, they stayed well within the normal range; (iii) no other trials have looked at the effect of supplementing with creatine on DHT levels, but 10 of the 12 trials looking at the effect of supplemental creatine on testosterone, five of which also looked at free testosterone, reported no effect; and (iv) the effect of supplemental creatine on hair loss hasn’t been directly studied.

With the above in mind, we can conclude that, although plausible, it seems unlikely that supplementing with creatine causes hair loss.