What creatine is
Creatine is a small compound your body already makes, mostly in the liver, and you also get it from meat and fish. It is stored in muscle, where it helps you produce quick bursts of energy. As a supplement, the most common and best-studied form is creatine monohydrate, a cheap white powder that mixes into water or any drink.
How creatine works
Inside muscle cells, creatine helps recycle the body's main short-term energy molecule, called ATP. During a hard set of lifts or a short sprint, your stored ATP runs down fast, and creatine helps it bounce back between efforts. The result is a little more work done per set, which over weeks adds up to more strength and muscle.
What the human research shows
This is one of the few supplements where the evidence is genuinely strong. A position statement from the International Society of Sports Nutrition, plus dozens of controlled trials and meta-analyses, agree that creatine improves strength, high-intensity performance, and muscle gain when combined with resistance training. The added strength is small per session but reliable across studies.
The benefit is not limited to young athletes. In adults over 50, adding creatine to a resistance programme produced bigger gains in muscle mass, strength, and physical function than training alone. Long-term studies up to two years have not shown serious side effects in healthy people. We grade the evidence as high. Creatine is probably the most cost-effective performance supplement there is.
What we still do not know
- Whether higher doses help people who do not respond to the standard amount.
- How creatine interacts with brain health and ageing over many years.
- Long-term effects in people with reduced kidney function, where data is thin.
How people take creatine
The simple plan is 3 g to 5 g of creatine monohydrate per day, taken at any time, every day. You can start with a one-week loading phase of 20 g per day split into four servings, then drop to maintenance. Loading is optional and just saturates muscle stores faster. Choose a product that is third-party tested, and check with your healthcare provider first if you have kidney concerns.