It is not necessary to take BCAAs (Branched-Chain Amino Acids) if you are already consuming sufficient amounts of protein through your diet or protein powder supplementation. This is because BCAAs are already present in high amounts in many protein-rich foods, including whey protein powder, which is a popular supplement for muscle building.
Most protein powders, particularly whey protein, contain all three BCAAs (leucine, isoleucine, and valine) in significant amounts. In fact, whey protein contains one of the highest amounts of leucine per gram of protein, which is particularly important for muscle protein synthesis (1).
Several studies have compared the effects of BCAA supplementation to those of protein supplementation on muscle protein synthesis and found that protein supplementation is more effective at promoting muscle protein synthesis and muscle growth than BCAA supplementation alone (2, 3).
That being said, there may be certain situations where BCAA supplementation could be beneficial, such as if you are following a low-protein diet or if you are exercising in a fasted state. In these situations, supplementing with BCAAs could help to promote muscle protein synthesis and prevent muscle breakdown during exercise (4, 5).
- Norton, L. E., & Layman, D. K. (2006). Leucine regulates translation initiation of protein synthesis in skeletal muscle after exercise. The Journal of nutrition, 136(2), 533S-537S.
- Churchward-Venne, T. A., Breen, L., Di Donato, D. M., Hector, A. J., Mitchell, C. J., Moore, D. R., ... & Phillips, S. M. (2014). Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men: a double-blind, randomized trial. The American journal of clinical nutrition, 99(2), 276-286.
- Jäger, R., Kerksick, C. M., Campbell, B. I., Cribb, P. J., Wells, S. D., Skwiat, T. M., ... & Smith-Ryan, A. E. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition, 14(1), 20.
- Shimomura, Y., Inaguma, A., Watanabe, S., Yamamoto, Y., Muramatsu, Y., Bajotto, G., ... & Mawatari, K. (2010). Branched-chain amino acid supplementation before squat exercise and delayed-onset muscle soreness. International Journal of Sport Nutrition and Exercise Metabolism, 20(3), 236-244.
- Tipton, K. D., & Ferrando, A. A. (2008). Improving muscle mass: response of muscle metabolism to exercise, nutrition and anabolic agents. Essays in Biochemistry, 44, 85-98.