Creatine is one of the most researched supplements in sport, and one of the most misunderstood. In this short article we look at what the studies actually show about creatine and testosterone.

How does creatine help, and why do athletes use it?

Your body makes creatine even if you don't take a supplement, and you get some from food, mainly red meat and fish. Most of it is stored in your muscles, where it helps regenerate energy (ATP) during short, intense efforts like sprints, tackles and heavy lifts.

A normal diet doesn't fill your muscle stores completely. Supplementing typically raises muscle creatine by around 20 to 40%, giving your muscles more to work with during hard efforts.

What do the studies show?

Creatine reliably improves performance in high-intensity exercise. Many studies have found that, combined with training, it helps increase strength, lean mass and repeated sprint performance. The International Society of Sports Nutrition's position stand (Kreider and colleagues, 2017) describes creatine monohydrate as the most effective supplement available for increasing high-intensity exercise capacity and lean body mass.

That's why it's popular with rugby players, strength athletes, sprinters and bodybuilders. Less commonly, it has also been marketed as a testosterone booster. Here's what the evidence says about that.

The three studies behind the testosterone claim

Three randomised controlled trials are usually cited to support the idea that creatine might raise testosterone.

Study 1 (2009). Twenty young rugby players were split into two groups. The creatine group took a loading dose (25 g a day) for one week, then 5 g a day for two weeks. Testosterone did not change in either group. However, the creatine group saw a significant rise in dihydrotestosterone (DHT), a more potent hormone made from testosterone, of about 0.12 ng/mL (from van der Merwe and colleagues, Clinical Journal of Sport Medicine).

Studies 2 and 3 (2011 and 2015). Both randomised around 20 active young men into two groups. After a week of 20 g a day, the creatine group in each study saw a significant rise in testosterone, while the placebo group saw no change: about 0.57 ng/mL in one study and 1.5 ng/mL in the other (Vatani and colleagues, 2011; Arazi and colleagues, 2015).

The changes in all three studies were statistically significant but small, and every participant stayed well within the normal range.

What do the other studies say?

At least ten other trials, with around 220 participants in total, have looked for a link between creatine and testosterone. They lasted from six days to ten weeks and used doses from 3 to 25 g a day, mostly creatine monohydrate. Participants included trained and untrained men, rugby players, footballers, runners and sprinters.

They found that creatine had no effect on testosterone.

A 2021 review of common questions about creatine, by a group of leading creatine researchers (Antonio and colleagues, in the Journal of the International Society of Sports Nutrition), reached the same conclusion: the overall evidence does not show that creatine increases testosterone. It also noted that the DHT finding from the 2009 rugby study has not been replicated. That matters because the DHT result is where the popular worry that creatine causes hair loss comes from; the review found no good evidence that it does. (In fairness, several of the review's authors have links to the supplement industry, which they declared.)

Conclusion

  • Three small studies hinted at a small testosterone or DHT increase from creatine.
  • At least ten others found no effect, and expert reviews conclude creatine doesn't meaningfully raise testosterone.
  • Creatine improves high-intensity performance, but you shouldn't take it to boost testosterone.

What this means for you

  • If you want creatine for performance, the usual evidence-based dose is 3 to 5 g of creatine monohydrate a day. A loading phase (around 20 g a day for 5 to 7 days) fills your stores faster but isn't essential.
  • Expect a small increase in body weight in the first weeks, mostly water stored in muscle.
  • Don't expect it to change your hormones. Training, sleep, enough food and a healthy body weight matter far more for normal testosterone levels.
  • Get your protein right first. Creatine helps at the margins; enough daily protein matters more for building muscle. If you struggle to hit your target from food, a protein shake is the next most useful supplement, and ParrotPal's round-up of the protein powders UK members actually use is a good place to start.
  • If you have a kidney condition or any other medical condition, or you're under 18, talk to a doctor before taking any supplement.

For how to train alongside it, see our rugby training guide.

References

  • van der Merwe J, Brooks NE, Myburgh KH. Three weeks of creatine monohydrate supplementation affects dihydrotestosterone to testosterone ratio in college-aged rugby players. Clinical Journal of Sport Medicine, 2009. PubMed 19741313
  • Kreider RB et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. JISSN, 2017. PubMed 28615996
  • Antonio J et al. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? JISSN, 2021; 18: 13. PubMed 33557850
  • Arazi H et al. 2015, and Vatani DS et al. 2011: the two trials reporting a testosterone increase, as cited in the original article.
  • Other trials cited in the original article: PubMed 21324203, 24633488, 12945829, 17136944, 11252073, 14685870 and 25804393; Volek JS et al. 1997, Journal of Strength and Conditioning Research 11(3): 182 to 187.