Creatine for 12 weeks: adults aged 45 to 65 gained lean mass in a small US trial

Creatine is best known as a gym supplement, but researchers are increasingly asking whether it could help muscle in midlife and beyond. A new 12-week trial from Texas A&M University, published on August 21, 2026 in the Journal of the International Society of Sports Nutrition, adds some data. Adults aged 45 to 65 who took creatine had more lean mass than those on placebo, with or without an exercise-and-diet program.

What the researchers did

Seventy-three healthy, previously sedentary adults were enrolled. First, each person chose whether to follow a structured exercise and weight-loss program (resistance and cardio training, with 300 to 500 fewer calories a day) or to carry on as normal. Then, within each choice, they were randomly assigned, double-blind, to creatine monohydrate (2 × 5 g a day, so 10 g in total) or a placebo of maltodextrin (a sugar-based powder) for 12 weeks. Sixty-four people (mean age 54.5; 40 women and 24 men) finished and were analyzed, in four groups of 13, 13, 18 and 20. Researchers measured body composition with DXA scans, plus strength, blood tests and a set of memory and thinking tasks.

What they found

• Lean mass, with exercise and diet: the creatine group gained 1.69 kg at 6 weeks (95% CI 1.0 to 2.4) and 1.27 kg at 12 weeks (0.56 to 1.98). The matching placebo group changed by -0.11 kg and +0.14 kg.
• Lean mass, without exercise or diet change: creatine was linked to gains of 0.99 kg and 1.1 kg at 6 and 12 weeks; placebo groups showed roughly no change.
• Body fat: in the exercise-and-diet groups, body fat percentage fell by 3.24 percentage points at 12 weeks with creatine versus 1.87 with placebo.
• Strength and endurance: the authors report gains in muscular strength and endurance with creatine.
• Blood markers: creatinine, a waste product commonly used to check kidney function, rose a little with creatine (6 to 8% without exercise, 16 to 18% with exercise) but stayed within normal ranges. The authors warn doctors not to misread this rise as kidney harm. Side effects were infrequent, mild and similar across groups.
• Memory and thinking: the authors say “selected markers” improved, but stress that these individual results are exploratory.

What this means for you

What this means for you

• What was studied: 10 g of creatine monohydrate a day for 12 weeks. That is higher than the 3 to 5 g a day the authors describe as typical low-dose use.
• Who was studied: healthy, sedentary adults aged 45 to 65, mostly women.
• What it shows: in this small group, creatine was linked to a modest gain in lean mass and, alongside exercise and diet, a bigger fall in body fat.
• Evidence strength (our simple scale: very low, low, moderate, high): low from this trial alone. Creatine overall has a larger body of research behind it.
• Read more in our beginner’s guide to creatine.

How strong is this evidence?

It is a randomized, double-blind trial, which is a good design, but a small one: only 13 to 20 people per group completed it. People chose whether to exercise rather than being assigned, so the exercise groups are not a clean comparison. The memory and blood-marker results were not the main focus and should be treated as early. The trial was posted on the ISRCTN registry in 2025, after enrollment began in July 2024. Funding came from an unrestricted gift by the WoodNext Foundation. AlzChem, a creatine manufacturer, supplied the supplement and paid for some blood tests. The lead investigator chairs AlzChem’s scientific advisory board. The authors say the sponsors were not involved in collecting, analyzing or interpreting data.

Sources

• Chun J, Liu Y, Kibler GL, et al. Effects of creatine supplementation with and without exercise and diet intervention on body composition, cognitive function, and markers of health in middle-aged and older adults. J Int Soc Sports Nutr 2026;23(sup1):2716273, published August 21, 2026. DOI: 10.1080/15502783.2026.2716273 / PubMed 42578920 (abstract and full-text copy read)
• Trial registry: ISRCTN83081058 (as cited in the paper)

This article is for information only and is not medical advice. Speak to a healthcare professional before changing medication or supplements.