Endurance and energy supplements are designed to improve the performance of athletes involved in high intensity aerobic activity. They assist by replacing fluids, replacing the electrolytes sodium & potassium lost in sweat, providing carbohydrate fuel for working muscles, enhancing ATP production, reducing fatigue, as well as enhancing mental focus and concentration. There are 2 main kinds of carbohydrates in energy supplements - simple carbohydrates such as sucrose, glucose and fructose, and complex carbohydrates, mainly maltodextrins and glucose polymers. Some products also include stimulants and other ingredients to further enhance performance. These include: Caffeine, Taurine, Guarana, B Vitamins, Ginseng, Ginkgo Biloba, L-Carnitine, Sugars, Anti-Oxidants, Glucuronolactone, Yerba Mate, Creatine, Acai Berry and Milk Thistle. Regardless of whether one is an amateur or seasoned professional, sports supplements can make a real difference to both performance and endurance levels.