GU Original Sports Nutrition Energy Gel is the energy gel that started it all. In 1993, Dr. Bill Vaughn developed the world's first energy gel to help his daughter perform better during ultra-marathons, and GU has been helping to propel the world's most successful extreme athletes to success ever since. GU Energy Gel sustains all forms of athletic activity with a highly compact, portable, and calorie-dense packet that is loaded with carbohydrates that can be rapidly absorbed. Branched-chain amino acids limit muscle fiber damage and increase speed of recovery, and extra electrolytes help maintain water balance. Some flavors feature caffeine to increase concentration. While the original formula has been tweaked and evolved over the years, the end result is still the same: GU Energy Gels fuel the best endurance athletes in the world. GU Original Energy Gel comes in a wide variety of good tasting flavors. Each packet contains 450mg of Amino acids, 100 calories, and at least 21g total carbs.