Taurine

The amino sulfonic acid, taurine, is one of the most abundant chemicals in the body. Taurine has been shown to act as an antioxidant and can improve endurance performance and increase repetitions to failure during strength training. However, antioxidants have been shown to impair muscle growth, so bodybuilders may not want to take taurine. Endurance athletes will garner the most benefits from taurine supplementation.

Reference: Zhang, M., Izumi, I., Kagamimori, S., Sokejima, S., Yamagami, T., Liu, Z., & Qi, B. (2004). Role of taurine supplementation to prevent exercise-induced oxidative stress in healthy young men. Amino Acids, 26(2), 203-207.