Creatine

Creatine is made in the body and also comes from foods such as meat and fish. Most of it is stored in muscle, where it helps recycle the energy used in short, intense efforts like sprinting or lifting.

As a supplement, creatine monohydrate is the form with the most research behind it. Studies in healthy adults show it can modestly improve strength, power and muscle gains when combined with resistance training. It appears less clearly useful for endurance sport.

It is generally well tolerated in healthy adults. Some people notice a small weight gain from extra water held in muscle, or an upset stomach. People with kidney disease, or who take medicines that affect the kidneys, should speak to a doctor first. Choose a product that has been independently tested for quality, and keep to the amounts on the label.