Creatine is a natural substance that is found in our bodies, particularly our muscles. It plays a very important role in energy metabolism by helping to produce ATP, the main source of energy for our cells. The additional creatine from supplements can increase muscle stores (the kind that retain, not that shops. Wink!), leading to improved performance during high-intensity activities like weightlifting and sprinting. It has also been shown to assist with muscle recovery and growth.