Personalized nutrition brand Gainful has added a new product to complement its existing line of protein powders: Gainful Hydration sticks, formulated to deliver an efficacious amount of four key electrolytes to help hydrate better than water alone. Available exclusively to Gainful subscribers, the Hydration sticks come in caffeinated and non-caffeinated versions in two flavors: Strawberry Lemonade and Lemon Lime.