Once the preserve of bodybuilders and sprinters, creatine is now being touted as everything from a brain booster to a healthy-ageing essential. But should we all be taking it? Not quite. “There’s really substantial evidence of creatine being effective,” says Bethan Crouse, a sports nutritionist at Loughborough University. “From a sport perspective, it’s probably one of the more well-researched supplements in terms of actually having a performance impact.” Creatine helps your body produce energy more efficiently during short, sharp bursts of activity. It does this by supporting generation of adenosine triphosphate (ATP), the body’s “energy currency”. The result? Improvements in peak power and a greater ability to sustain repeated high-intensity efforts, such as sprint intervals. More recently, attention has shifted beyond the gym. Early research suggests creatine could have a role in cognitive function, with some studies pointing to protection from cognitive decline.…