How the study worked
The researchers ran a 12-week, double-blind, placebo-controlled trial, published in the Journal of the International Society of Sports Nutrition. Seventy-three healthy but sedentary adults started, and 64 of them, aged 45 to 65 (40 women and 24 men), made it to the end.
First, participants chose whether to join a structured exercise and weight-loss programme or carry on with their normal lives. Within each of those groups, they were then randomly assigned to take either creatine monohydrate or a placebo, 5 g twice a day. That meant there were 4 groups: creatine or placebo, with or without exercise.
The exercise groups trained 3x per week with a mix of resistance and aerobic work, and followed a diet with a modest calorie deficit. Body composition was measured with DXA scans at the start, after 6 weeks and after 12 weeks, alongside blood tests and cognitive tests.
Muscle gains without the workouts
This is the most shocking result. Among participants who stayed sedentary, those taking creatine gained roughly 1,1 kg of lean tissue over 12 weeks. They also got stronger on the leg press and bench press and improved their muscular endurance, all without following any training plan.
The non-exercising creatine group also showed favourable changes in some blood lipids, a drop in HbA1c (a marker of long-term blood sugar control) and better scores on selected memory and cognitive tests. The authors describe these cognitive and blood marker findings as exploratory, so treat them as interesting hints rather than proof.
Losing fat without losing muscle
Dieting comes with an annoying side effect: some of the weight you lose is muscle. The exercise half of the study tackled exactly that problem.
- Exercise and diet with placebo: Participants lost fat but saw little change in lean tissue.
- Exercise and diet with creatine: Participants added nearly 1,4 kg of lean tissue while still losing fat mass, and saw a larger drop in body fat percentage.
According to the researchers, this is the first study to show that adding creatine to an exercise and weight-loss programme reduces body fat percentage more than exercise and diet alone. Strength gains were bigger too. Leg press maximum rose by about 34% with creatine versus 18% with placebo, and bench press by about 23% versus 12%. Time to exhaustion also improved more in the creatine group.
Why your aerobic engine stays the same
One thing creatine did not do was boost aerobic capacity beyond what exercise achieved on its own. That fits decades of research. Creatine tops up your muscles’ stores of phosphocreatine, a rapid-release energy reserve that regenerates ATP during short, hard efforts. Think of it as a turbo boost for the first few seconds of a sprint, not a bigger fuel tank for a 3-hour ride.
Dr Richard Kreider, who led the study and has researched creatine for more than 30 years, has long argued that its value reaches well beyond sport. “Creatine is safe, and it’s important for everybody, not just bodybuilders and athletes,” he said in a 2025 interview with Texas A&M. A 2025 analysis by his team of 685 clinical trials found no significant difference in reported side effects between creatine and placebo.
Important caveats
Water counts as lean tissue: Creatine draws extra water into muscle cells, and DXA scans count that as lean mass. Some of the gain may be water rather than new muscle.
Self-selected groups: Participants chose whether to exercise, so the two halves of the study may differ in motivation or lifestyle. Only creatine versus placebo was randomised.
Short and specific: Twelve weeks in healthy 45 to 65-year-olds tells us nothing about long-term effects or younger, trained riders.
High dose: 10 g a day is more than the 3 to 5 g commonly used. Kreider notes that getting it from food would mean eating roughly 2 to 4,5 kg of meat or fish every day. So supplementing is a must.
Creatine is no replacement for training, and the biggest gains came when it was paired with exercise. But if you want to reach your sixties with legs that still have a sprint in them, a daily scoop might be one of the simplest habits you can add.