What creatine actually does
Creatine is a naturally occurring compound made from three amino acids (arginine, glycine, and methionine). About 95% of the body's creatine is stored in muscle as phosphocreatine — an immediately available energy source used to regenerate ATP during short, high-intensity efforts.
When you sprint, lift heavy, or perform any explosive effort lasting under ~10 seconds, phosphocreatine is the primary energy system. Supplementing with creatine increases the muscle's phosphocreatine stores by 10–40%, which means you can sustain high-intensity efforts slightly longer before fatigue sets in.
📊 What the evidence shows
Across hundreds of studies, creatine supplementation consistently produces: 5–15% improvements in strength and power output, 1–2 kg of lean mass gain over 4–12 weeks (largely from increased water retention in muscle and enhanced training capacity), and faster recovery between high-intensity bouts.
Who benefits most
Strength and power athletes
The most robust evidence is for activities requiring repeated bursts of high-intensity effort — weightlifting, sprinting, rowing, team sports. If your training involves heavy compound lifts or speed work, creatine will likely improve your performance.
Vegetarians and vegans
Creatine is found almost exclusively in animal muscle tissue. People who don't eat meat have lower baseline creatine stores and typically see larger gains from supplementation than omnivores. This makes creatine one of the most evidence-supported supplements for plant-based athletes.
Older adults
Research in adults over 50 shows creatine supplementation combined with resistance training produces greater improvements in muscle mass, strength, and functional capacity than training alone. It may also have benefits for bone density and cognitive function.
Who probably won't notice much
Endurance athletes see limited benefit — creatine's mechanism is specific to short-duration, high-intensity efforts. If your training is primarily steady-state cardio, the effect size will be small.
How to take it
Creatine monohydrate is the form used in virtually all research. It's the cheapest, most bioavailable form available, and there's no meaningful evidence that more expensive forms (creatine HCl, buffered creatine, ethyl ester) perform better.
Dosing
- Standard dose: 3–5g per day, taken consistently
- Loading phase (optional): 20g/day split into 4 doses for 5–7 days, then drop to 3–5g/day maintenance. Saturates muscle stores faster but isn't necessary — the same saturation is achieved in ~4 weeks with the standard dose
- Timing: Not critical. Post-workout with protein and carbohydrates may offer a slight advantage, but total daily intake matters more than timing
The weight gain question
Most people gain 0.5–1.5 kg when starting creatine — this is water retention in muscle tissue (intracellular, not subcutaneous). It's not fat gain, and it doesn't make you look "puffy." It's the creatine drawing water into muscle cells, which is part of the mechanism that supports performance.
Is creatine safe?
Yes. Creatine is one of the most thoroughly safety-tested supplements in existence. Years of research have found no evidence of harm to the kidneys, liver, or any other organ in healthy adults at standard doses. The myth that creatine damages kidneys originated from a single case report involving a person with pre-existing kidney disease — it does not apply to healthy individuals.
People with pre-existing kidney conditions should consult their doctor before supplementing with creatine, as it increases creatinine levels in blood and urine (which are used as markers of kidney function).
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