Adults aged 45 to 65 gained 2.4 pounds of muscle on creatine without touching a weight

Richard Kreider has spent decades studying creatine, and his newest trial at Texas A&M University landed on an unusual group: people in midlife who took the supplement and did not train. Among the 64 healthy adults aged 45 to 65 who finished the 12-week study, those who did not exercise and took creatine gained about 2.4 pounds of lean tissue.

Kreider directs the university’s Exercise and Sport Nutrition Lab. Participants took 10 grams of creatine monohydrate or a placebo daily, and each sat in an exercise or a non-exercise arm. The WoodNext Foundation funded it through the Texas A&M Foundation, and results appeared in the Journal of the International Society of Sports Nutrition.

Ten grams a day, no gym membership

The finding that gives the study its hook came from the non-exercise arm. According to the Texas A&M release, those volunteers added roughly 2.4 pounds of lean tissue over the 12 weeks and also improved leg press and bench press strength. Participants in the placebo groups showed little change in lean tissue, by the account in ScienceDaily’s summary of the trial.

The dose matters. Ten grams is well above the three to five grams usually cited for maintenance, and Kreider argued food cannot easily deliver it. “Reaching a daily intake of 10 grams from diet alone would require eating roughly five to 10 pounds of meat or fish each day,” he said, which is his case for supplementation as the practical route.

Exercise and a calorie-restricted diet, with creatine added

Volunteers who trained and followed a calorie-restricted diet got more from the supplement than those on the same program with placebo. In the university’s account, the creatine group posted larger gains in leg press strength, bench press strength and time to exhaustion, and added nearly three pounds of lean tissue while losing fat mass. The placebo group on the same exercise and diet plan showed little change in lean tissue.

Secondary reporting on the paper put numbers on the strength side. Lifespan.io’s breakdown lists leg press gains of 34 percent with creatine and exercise versus 18 percent with exercise and placebo, and bench press gains of 23 percent versus 12 percent, plus a body-fat reduction of about 3.2 percent versus 1.9 percent. Creatine did not improve aerobic capacity beyond what the training itself delivered.

Lean tissue is a stand-in for muscle

Every report on the trial describes the 2.4 pounds as lean tissue, not as biopsied muscle fiber. Body composition was read by dual-energy X-ray absorptiometry, a scan that sorts the body into fat, bone and everything else, and Lifespan.io points out that creatine pulls water into cells, so part of any scan-measured gain can be fluid rather than contractile tissue. Muscle is the largest component of lean tissue, which is why ScienceDaily’s coverage describes the result as muscle building. The strength improvements in the non-exercise group are the firmer hint that muscle function changed, but none of the trial summaries cleanly separate water from protein.

Design limits cut in the same direction, and they are not small. Participants chose whether to join the exercise or non-exercise arm before being randomized to creatine or placebo, which the authors acknowledged could introduce differences between the groups, and the trial was small and lasted only 12 weeks. The published summaries also do not give a head count for each of the four arms, so the size of the 2.4-pound gap against placebo cannot be checked independently, and the shape of any dose response is unknown because only one dose was tested. Women made up 40 of the 64 finishers, which is a useful skew for a midlife population but means the male subgroup was only 24 people.

The safety record behind the dose

Safety is the usual objection to a 10-gram habit, and Kreider has a stake in the answer. He is the lead author of a 2025 analysis of 685 clinical trials, covering 12,839 creatine users and 13,452 placebo participants, which concluded that supplementation does not increase the prevalence or frequency of side effects compared with placebo, with reported rates of 13.7 percent against 13.2 percent. Because the same researcher produced both the safety review and the new trial, outside replication carries extra weight.

Independent guidance is more cautious in tone. Mayo Clinic describes creatine as likely safe for many people for up to five years at recommended doses, lists weight gain as the main side effect, and says studies in healthy people have not found kidney harm, while telling anyone with kidney disease to consult a clinician first.

What the trial can and cannot say is narrow: in 64 healthy adults over three months, a daily 10-gram dose coincided with measurable lean-tissue and strength gains even without training. Whether that holds for a year, in people with chronic disease, or measured by scans that isolate muscle from water remains for larger studies to settle.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

More from Morning Overview