Thinking about trying creatine? This is what you need to know: Think of creatine as muscle medicine – the extra strength formula. When you supplement your diet with this amino acid, you spur the production of proteins your body uses to weave muscle fibers, says Dr Douglas Kalman, a sports nutritionist at Florida International University. “Using creatine while weight training typically enhances strength gains by five to 15% in the first month, with no side effects,” he says. In fact, a landmark study from Belgium confirmed that daily use of creatine by healthy adults for as long as five years does not affect the kidneys. That said, people with diabetes or a kidney disorder should steer clear, since their already overworked organs may have trouble processing the extra fuel. As for which type to buy, Kalman recommends sticking with classic creatine monohydrate – it’s as effective as newer formulas but less expensive. For the first month, take five grams a day, mixed into your post-workout recovery shake. On rest days, consume your five grams at any time. After the first month, drink five grams after training.