Creatine has long been popular among athletes. Olympians tout it, fitness influencers experiment with it, and Patrick Schwarzenegger’s gym bro character in The White Lotus added it to his famous shake.

It’s primarily considered a fitness supplement, but doctors are increasingly curious about its potential longevity and mental health benefits.

But is creatine really useful, and are there any downsides? Here’s what experts say.

What is creatine?

Creatine is a compound the body naturally makes in the liver, kidneys and pancreas. We can also get it from animal proteins like red meat, fish and chicken. It acts as a quick fuel source for muscles, helping regenerate adenosine triphosphate, or ATP – a molecule cells use for energy.

“If we keep it super simple, the body has three sorts of energy systems,” says Dr Imtiaz Desai, a Sydney, Australia-based exercise physiologist.

Creatine helps power short-duration, high-intensity activities like sprinting or lifting, and also those requiring moderately sustained energy, like tennis or hockey. But it doesn’t do much for prolonged, slow-burn energy like the kind you need to run a marathon.

If you’re doing resistance training, it helps muscles work harder for a little longer. “It should enable you to do a few more repetitions at the same weight,” says Desai.

Most people don’t need creatine supplements for general health – the body makes enough, aside from in rare and serious cases of genetic creatine deficiency disorder. Nonetheless, the fitness-minded often take it to optimize their workouts.

Synthetic creatine comes in different formulations, but creatine monohydrate is the most studied, with the strongest evidence for efficacy. It’s widely available, often sold as a flavorless, grainy white powder, and affordable: dosages vary based on personal goals, but a typical daily serving of five grams might cost about 50 cents (38p).

Is creatine safe?

In healthy adults, creatine is considered safe even for long-term use – it’s one of the most researched supplements available.

While the UK regulates dietary supplements, in the US, the Food and Drug Administration does not vet the accuracy of supplement contents, so it’s possible for products to be contaminated with other substances or contain less creatine than advertised. Products with the NSF seal are more reliable, as they have been tested by a third-party regulator.

Creatine is known to cause minor side-effects like bloating or stomach pain. These can be more pronounced in people taking higher doses, such as 25 or 30 grams a day, in a dubious practice known as “loading”.

“There’s no need for a loading phase,” says Dr Avinish Reddy, a Los Angeles-based physician with a longevity-focused practice.

Higher doses of creatine create more waste for the kidneys to filter, so people with kidney issues should check with a doctor before starting the supplement, says Reddy. Recently, creatine “loading” was linked to acute kidney injury in a 17-year-old boy.

It’s best to take creatine mixed into a liquid, like juice, water or a smoothie, as opposed to “dry-scooping”, an influencer stunt in which people eat straight creatine. This method risks powder inhalation and choking, along with worse GI effects.

Does creatine actually help build muscle?

The short answer: not as much as the hype suggests.

Desai led a 12-week study, published this March, in which two groups of people began a weight-lifting regimen. One group used creatine, the other did not. There was no meaningful difference in results: people in both groups gained approximately two kilograms of lean body mass on average.

In the short term, creatine draws water into muscles, which can cause a couple of pounds of temporary weight gain and make muscles look more full. “There’s a short-term change in body-water content,” says Desai, who posits that past studies that found small benefits with creatine supplementation may have overestimated creatine’s relationship with muscle growth by not accounting for this water retention.

Desai says it’s possible that longer studies might provide more information about creatine’s muscle-building benefits over time. It is also possible that creatine may indirectly boost muscle growth by allowing people to train harder. “If you’re able to do more repetitions, then over time, we would expect you to see an added benefit,” Desai says.

But don’t expect an overnight change. “You’re not going to pack on pounds of muscle within a few weeks,” he says, nor will adding creatine to an otherwise sedentary lifestyle yield results.

Who benefits most from creatine?

Creatine is often associated with athletes looking for an edge, but supplementation also can be helpful for older adults experiencing muscle loss. “Women experience a lot of muscle mass and strength loss after menopause,” says Reddy, who often recommends a standard daily dose of three to five grams of creatine to patients. It can help with resistance training and post-workout recovery by activating satellite cells, which repair muscle fibers after injury caused by use.

Vegetarians and vegans who supplement with creatine may also see greater improvements in their workouts and energy levels, since their diets contain less natural creatine.

However, researchers estimate that about 20%-30% of people are “non-responders” to creatine due to physiological factors like genetics.

Can creatine support mental health?

Researchers are exploring whether creatine may help ease depression symptoms by supporting brain energy, memory, attention and information processing speed, and promoting dopamine and serotonin production.

Dr David Puder, Florida-based psychiatrist and host of the Psychiatry & Psychotherapy podcast, sees creatine as a promising tool in treating depression. It is not necessarily a standalone solution, but can be part of a broader, physician-led approach to treating depression, along with therapy and optimizing diet, exercise and sleep.

“Studies to date have shown that creatine seems to amplify the speed at which people recover [from depression] by a little bit,” says Puder. “Not a lot, but a measurable improvement,” he says, particularly in clinical trials pairing creatine with medications such as Lexapro or cognitive behavioral therapy.

It may be that creatine’s exercise-boosting effects also support mental health. “Exercise improves the ability to come out of depression,” says Puder, so better workouts “may allow for an independent improvement in depression beyond what the creatine is doing in the brain”.

While creatine may help alleviate the mental fatigue that comes with depression, Puder says that in people with bipolar disorder, there is some risk of it contributing to hypomania. If you are interested in starting creatine, you should talk to your doctor beforehand.

Is creatine safe for young people?

While creatine itself is generally safe for adults, most medical organizations, including the American Academy of Pediatrics, recommend against creatine use for those under 18 due to unknown long-term effects. However, there are no age restrictions on who can buy creatine, and a 2024 review found 26% of adolescent boys said they had taken creatine at some point.

The University of Toronto researcher Dr Kyle Ganson also cautions that creatine use by teens can be part of a broader pattern.

Ganson recently studied a cohort of 912 teenagers and young adults. He found that those who used creatine, particularly young men and boys, were more likely to develop muscle dysmorphia – an obsessive drive for size and muscularity that can lead to psychological fallout.

“It’s not causal,” says Ganson. “Just because you take creatine, you’re not going to develop a mental health condition.” But it may be a sign that a young person is becoming overly focused on body image.

Ganson urges parents to exercise “respectful curiosity” about their child’s goals with the supplement, and to talk to a doctor or dietitian, especially if their child’s focus on physical appearance seems to be disrupting other areas of their life.