- Created primarily for hydration, GU Hydration Drink Tabs offer the athlete a low-calorie drink option. GU Hydration Drink Tabs are reformulated with xylitol to help reduce gastrointestinal distress when compared to sorbitol. Sodium, the primary electrolyte lost in sweat, helps maintain water balance. Use GU Hydration Drink Tabs before, during, and after exercise to hydrate and replenish electrolyte levels. Drop one tab into 16 oz (475ml) of water. pre-hydrate before activity. During the activity, drink 20-30 oz per hour (590-890ml). Made with vegan ingredients.