Creatine is usually associated with gym performance, but a controlled trial in middle-aged adults suggests its effects may extend beyond people following a structured training programme. Over 12 weeks, sedentary participants taking creatine gained lean tissue and improved strength even when they did not join the study’s exercise intervention.
The trial, published in the Journal of the International Society of Sports Nutrition, examined whether creatine monohydrate could influence body composition, physical performance, cognition and selected health markers in adults aged 45 to 65. The question is increasingly relevant as preserving muscle becomes more difficult with age and as weight-loss strategies can reduce lean tissue alongside body fat.
Seventy-three healthy sedentary adults entered the study and 64 completed the full intervention. The analysed group had an average age of 54.5 years and included 40 women and 24 men. Participants first chose whether they would enter a structured exercise and diet programme or remain in the non-exercise condition. Within those strata, they were randomly assigned in double-blind fashion to receive either creatine monohydrate or a maltodextrin placebo.
The creatine dose was 10 grams per day, divided into two 5-gram servings. Researchers assessed participants at baseline, six weeks and 12 weeks using DXA scans for body composition, fasting blood samples, strength and endurance measures, cognitive tests and questionnaires.
Lean tissue increased even without structured training
The clearest result came from body composition. Among participants who did not take part in the structured exercise programme, creatine supplementation increased lean tissue mass by roughly 1.1 kilograms, or about 2.4 pounds, over 12 weeks. The non-exercising creatine group also improved leg and bench-press strength and muscular endurance.
That finding does not mean exercise is unnecessary. Rather, it suggests that creatine may influence lean tissue and muscular performance even before the additional stimulus of formal training is considered. For adults approaching the age at which muscle loss becomes increasingly important, that distinction could matter.
The exercise groups followed a substantially more demanding programme. Participants trained three times per week for 12 weeks, combining whole-body resistance exercise with about 20 minutes of aerobic activity at 60% to 80% of heart-rate reserve. Resistance workloads were progressively increased, while participants were also encouraged to accumulate 10,000 steps on non-training days.
Those participants simultaneously followed a diet intended to produce a modest energy deficit of around 300 to 500 kilocalories per day. This created a useful test of whether creatine could help preserve or build lean tissue while body weight was being deliberately reduced.
Exercise, dieting and creatine produced a different body-composition pattern
After 12 weeks, participants combining creatine with exercise and the weight-loss diet had gained about 1.27 kilograms of lean tissue. The corresponding exercise-plus-placebo group showed little overall change in lean tissue.
Creatine was also associated with a greater reduction in body-fat percentage during the exercise and diet intervention. The researchers described this as an important result because deliberate weight loss can involve a trade-off: reducing fat mass while trying to retain the muscle that supports strength, mobility and metabolic health.
Strength and muscular endurance improved more broadly when creatine was combined with training. The exercise programme itself remained central, however. Creatine did not provide an additional improvement in aerobic capacity, which is consistent with its better-established role in supporting short-duration muscular energy rather than endurance adaptations.
Cognitive findings are promising but more tentative
The study also assessed cognition, including memory-related outcomes. Selected measures improved in participants receiving creatine, both with and without the exercise intervention. This fits a growing research interest in creatine as an energy-supporting compound not only in skeletal muscle but also in tissues with high energy requirements such as the brain.
These results require more caution than the body-composition findings. The researchers explicitly classified individual cognitive and biomarker analyses as exploratory, and multiple distinct outcomes were examined without an across-outcome adjustment. Practice effects from repeatedly completing cognitive tests also cannot be completely excluded.
Selected blood lipids and HbA1c also changed favourably in some analyses, but these outcomes similarly need confirmation in larger trials designed specifically around metabolic endpoints. The intervention was reported as well tolerated over the 12-week period.
What the trial can and cannot establish
The design provides stronger evidence for the comparison between creatine and placebo within each exercise condition because supplement allocation was randomized and double-blind. The comparison between exercising and non-exercising participants is less secure because participants chose whether to enter the exercise programme rather than being randomly assigned to it.
The sample was also relatively small, with 64 people completing the trial, and the intervention lasted only 12 weeks. That limits conclusions about long-term muscle preservation, sustained weight management or clinical outcomes. The researchers highlighted the need for further work on age-related muscle loss and on people undergoing pharmacological weight-loss treatment.
There is another measurement consideration. Creatine intake and changes in muscle mass can affect creatinine, a blood marker commonly used to estimate kidney filtration. The study did not have cystatin C or directly measured filtration available, so creatinine-based kidney estimates need to be interpreted carefully in this setting.
For middle-aged adults, the practical significance is therefore narrower than a claim that a supplement can replace training. The trial instead shows that creatine produced measurable lean-tissue and strength changes even in sedentary participants, while the combination of creatine, structured exercise and a calorie-controlled diet produced a broader pattern of improved body composition and physical performance.
That makes the study particularly relevant to healthy ageing research. As people move through midlife, the objective increasingly shifts from simply lowering body weight to preserving the functional tissue that supports strength and independence. In this trial, creatine appeared to move that balance in a favourable direction, but larger and longer studies will be needed to determine how durable those gains are.
Source Information
Study Title: 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
Authors: Jisun Chun, Yuhang Liu, Giuliet L. Kibler, Hudson Lee, Khatereh Babakhani, Nathaniel Rhoades, Ian Bivins, Joungbo Ko, Broderick Dickerson, Drew E. Gonzalez, Ryan J. Sowinski, Chris J. Rasmussen and Richard B. Kreider
Journal: Journal of the International Society of Sports Nutrition
Year: 2026
DOI: 10.1080/15502783.2026.2716273
