Which supplements are of most interest for exercise and muscle gain?

Supplements may benefit exercise performance and muscle gain by providing a convenient form of energy and nutrients (e.g., powdered proteins such as whey protein or vegetable protein sources, carbohydrate drinks and gels), correcting or preventing nutrient deficiencies, improving recovery from exercise, or enhancing exercise performance directly.^[1] The supplements of most interest for enhancing exercise performance directly are creatine, caffeine, nitrate, citrulline, beta-alanine, and sodium bicarbonate.^[1]