Talk to any young athlete, and they'll know about creatine.
It's one of the most popular supplements for improving muscle recovery and preserving muscle mass – used by gym junkies around the world.
Now, new research adds to tentative evidence that creatine may benefit the body and brain even without exercise.
Creatine may not directly cause fat loss, but initial findings suggest it may stall the loss of muscle mass, even without resistance training.
The supplement could even have benefits for memory and cognitive function.
The recent study was published in the Journal of the International Society of Sports Nutrition.
The trial included 64 sedentary adults, aged 45 to 65, who were randomized to take either a placebo or a high dose of daily creatine (10 grams) for 12 weeks.
Neither researchers nor participants knew who was taking what.
During this time, volunteers could decide for themselves whether or not they wanted to participate in an exercise and diet intervention.
Among the 26 who opted out of this intervention, those who took creatine still increased their lean tissue mass as well as their bench press and leg press strength.
That was true even though they hadn't increased their resistance training.
Still, that doesn't mean exercise has no role to play in creatine consumption.
Among the 38 participants who changed their physical activity and diet, the results of creatine were even more impressive.
The supplement led to a greater reduction in body fat percentage and improved muscular strength and endurance on bench presses and leg presses after 12 weeks.
There were even signs that creatine boosted cognitive function and scores on memory tests in those who did and didn't exercise, although those results are only exploratory.
"These findings may have important implications for middle-aged and older individuals seeking to reduce body fat while maintaining muscle mass and cognitive function," write researchers from Texas A&M University.
"[They] support contentions that creatine supplementation can help older individuals maintain muscle mass, strength, and cognitive function."
To the researchers' knowledge, this is the first study to show that adding creatine to an exercise and diet-induced weight-loss program can produce a greater reduction in body-fat percentage than exercise and diet alone.
The study's senior author, Richard Kreider, has studied creatine for more than 30 years.
He currently chairs the scientific advisory board of Alzchem, the creatine manufacturer that supplied the supplements used in the trial and funded one set of laboratory tests, although, according to the paper, the company was not involved in collecting, analyzing, or interpreting the new data.
The results show perks for creatine even without exercise, and that is a contentious result.
Earlier this year, on the Health vs Hype podcast, Jason Mitchell, the chief medical officer at healthcare company Geisinger, explained that there are some really good studies showing that elderly people who do strength training and take creatine supplements maintain more lean body mass.
But Mitchell remained unconvinced that creatine supplements worked without exercise.
"I think sometimes you'll see influencers saying, take creatine and you can lose fat, and that is not true. The reason that it works is if you're taking creatine while doing weight training increase lean body mass and that ultimately decreases fat," said Mitchell.
"So that's one of those misconceptions."
Previous trials investigating creatine supplements without exercise have produced mixed results.
In 2019, for instance, a two-year randomized trial that involved roughly 200 older women found no improvement in lean mass or muscle strength without resistance training.
But that trial didn't directly compare resistance training to no training, like this new study did.
Creatine is one of the most extensively studied sports and nutritional supplements, but its role outside of the gym is just coming to light.
When creatine first exploded in popularity in the 1990s, it was because scientists found that the supplement could improve athletic performance.
Most of those early studies, however, focused on people who were training regularly.
More recently, the conversation around creatine has expanded beyond the gym and grabbed the interest of others.
Emerging evidence, for instance, suggests that creatine may boost brain function, memory, or even mood.
"It's intriguing. It's not definitive at this point," said Mitchell about emerging data.
"Certainly there's nothing that shows improvements with dementia and that type of thing."
The brain uses a lot of energy, Mitchell explains, and creatine is in the brain. But how it impacts cognition at this point is uncertain.
"We don't have the data to say, yeah, this is something you should be taken for your brain, but I don't want to discount that. There are some studies out there," he said.
What's even less clear is the dose required to reap the most benefits. The current study had participants take a relatively high dose of creatine, equivalent to eating roughly 2 kilograms (4.5 pounds) of meat or fish each day.
But is that helpful for everyone?
Creatine has become a "billion-dollar darling of the wellness aisle" since research has started to tie it to longevity.
But supplements are expensive, and they may not work or be safe for everyone to take.
It's easy for hype online to outpace the actual evidence, and it's important to remain cautious about what any one supplement can achieve.
For now, it seems that creatine may complement exercise, but it certainly can't replace it.
The research has been published in Journal of the International Society of Sports Nutrition.
This article was fact-checked by Rebecca Dyer and edited by Rebecca Dyer. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.