Creatine: What It Does and Who It Helps

Creatine is a simple compound your body makes from amino acids and stores mostly in muscle and, to a smaller extent, in the brain. In muscle, it helps recycle ATP: the quick energy currency your cells use during short, intense efforts. In the brain, creatine supports energy-demanding tasks and may buffer fatigue. It is one of the most studied supplements in sport and health. The picture that emerges from modern research is straightforward: when used properly, creatine helps many people perform better, recover more consistently, and preserve muscle across the lifespan. But it's no miracle compound.

How creatine works (in plain language)

Your muscles carry a reserve of phosphocreatine. During a sprint, heavy lift, or hard interval, phosphocreatine donates a phosphate to rebuild ATP in milliseconds. With better stores, you repeat quality efforts with less drop-off. Over weeks of training, that extra quality translates into more total work, slightly faster progression, and to an extent: more lean mass. In the brain, similar energy buffering can help during tasks that are short, intense, or done when you are sleep-restricted.

Everyday adults

Most adults who are active a few times per week will notice creatine’s benefits during strength sessions, high-intensity classes, or hill sprints. The change is not miraculous in any way. It is an extra rep before fatigue, a steadier effort across sets, and less of a “falling off a cliff” feeling late in a workout. Over months, that adds up to better strength and body composition, especially if your protein intake and sleep are decent. Safety data in healthy adults continue to be reassuring when routine doses are used and hydration is reasonable.

People trying to lose weight

When calories drop, muscle is always at risk. Preserving lean mass keeps resting energy burn higher, maintains strength, and helps you feel better during training. Multiple trials show that creatine, combined with resistance exercise, helps maintain or slightly increase lean mass during a cut. It won’t make fat loss automatic; it simply protects the tissue you want to keep while you do the work. Water shifts within muscle can nudge scale weight by a small amount early on; that’s intracellular and not the same as fat gain.

Endurance athletes

Creatine is not just for lifters. Runners, cyclists, and team-sport athletes benefit in efforts that require surges: short climbs, attacks, accelerations, repeated sprints, and final-lap kicks. Some endurance athletes hesitate because of the small early water gain; in practice, this is usually modest and can be timed around racing blocks. There is also emerging interest in creatine for concussion recovery and high-altitude adaptation. The evidence there is growing, but not as mature as the strength and power data. Notably the water retention is overrated to an extent.

Older adults

Aging blunts the muscle-building response to standard protein meals and makes it easier to lose strength after illness or inactivity. Trials in adults over 60 show that creatine paired with simple resistance training improves gains in strength and fat-free mass compared with training alone, and can support functional tasks like chair-stands or stair climbing. There are also encouraging signals for bone-related outcomes when creatine accompanies resistance work.

Cognitive and neurofatigue angles

Results vary by task and population, but several studies report small cognitive benefits in situations where brain energy is strained: sleep restriction, demanding short-burst tasks, or low dietary creatine (e.g., some vegetarians). Effects are not universal and should be framed as supportive rather than transformative. Still, the direction of evidence is positive, and the safety profile in healthy adults is favorable.

Neurocognitive benefits from any compound are quite challenging to study.

Safety and common concerns

Modern reviews in healthy people report no harm to kidney or liver function when creatine is used at typical doses and hydration is adequate. Temporary stomach upset can occur if you take large doses all at once (ex. 10-20 grams at once). Muscle cramping has not been shown to increase with creatine in controlled studies.

Practical notes

Most people use a small daily dose and allow stores to rise over a few weeks. Others choose a brief loading phase to saturate faster. Either approach can work when paired with training and protein-anchored meals. Consistency beats exotic timing. If you pause during travel or injury, you can resume later without “resetting” your body.

Who might skip it

If you have a diagnosed kidney condition or are on medications that affect kidney function, discuss creatine with your clinician first. If you are preparing for a sport with strict weight classes or appearance scoring, plan your timing to avoid early water-related weight changes in the days right before competition.

Bottom line

Creatine enlarges your “high-octane” fuel reserve. For athletes, that means better quality work and improved strength and power over time. For everyday people, it means a bit more output with less fade across sets. For older adults, it supports the training that keeps muscle and function. Cognitive benefits appear in specific contexts where brain energy is taxed. Put simply: creatine is a well-studied tool with a favorable safety profile in healthy adults when used as part of a sensible routine.

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References (recent)

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3. Forbes SC, Candow DG, Ostojic SM, et al. Creatine supplementation during resistance training in older adults: benefits and considerations. Nutrients. 2021.

4. Chilibeck PD, Kaviani M, Candow DG, Zello GA. Creatine supplementation in older adults—updated perspectives. Nutrients. 2021.

5. Dolan E, Gualano B, Rawson ES. Beyond muscle: a systematic review of creatine for brain health. Nutrients. 2019.

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7. Forbes SC, Candow DG, Krentz JR, et al. Creatine and bone health: current evidence. Nutrients. 2022.

8. Sousa M, Teixeira VH, Soares J. Creatine supplementation and kidney function in healthy adults: systematic review. J Int Soc Sports Nutr. 2021.

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10. Smith-Ryan AE, Cabre HE, et al. International society updates on creatine use across the lifespan. J Int Soc Sports Nutr. 2022.