What Are BCAAs & Their Benefits?

The three branched-chain amino acids are a supplement that have been popular since the 1980s, but are they still suitable for people looking to build muscle mass? This article will help bring you up to speed with the current scientific consensus and specify the scenarios in which BCAAs can have the most significant impact.
In this article, you'll find:
What are BCAAs?
How do BCAAs work?
Benefits of BCAAs
When to take BCAAs
Dosage and side effects for BCAAs
What are BCAAs?
Amino acids are used to build muscle protein and BCAAs are often supplemented to boost muscle growth and improve performance. Leucine is a particularly essential BCAA as it acts as a signal that ‘switches on’ muscle protein synthesis (the process of building muscle).1 BCAAs are found in a variety of high-protein foods. They are also available as a supplement in powder or capsule form.
How do BCAAs work?

BCAA Benefits
Muscle Hypertrophy AKA increased muscle growth
Muscle Soreness and Recovery
Low Protein Meals
Protein Sources Low in BCAAs
Appetite

When to take BCAAs
Before and during a workout: BCAAs can be taken before a workout to spark muscle building while you're still working out and to prevent muscle fatigue. One study has shown that muscle fatigue was reduced by 15% by supplementing with BCAAs during a workout.11
After a workout: You can also take BCAAs after a workout to improve your recovery post-workout with studies reporting reduced muscle soreness and better performance in training sessions in the days following supplementation when compared to a placebo.12,13
BCAA Dosage
Side Effects
Taking BCAAs is generally safe and the majority of people won't have any side effects.
There are a few conditions where it may not be advisable for you to take BCAAs, so if you have any concerns, then please speak with your doctor before taking.
Take Home Message
FAQ
What are BCAAs?
BCAAs are the three essential branched chain amino acids, namely leucine, isoleucine and valine.
What are the benefits of BCAAs?
The benefits of taking BCAAs include increased muscle growth, mucle recovery, and benefitting meals which are low in protein.
When should I take BCAAs?
Evidence suggests that the optimal times to take BCAAs are around a workout, so before, during and immediately after your training session.
What dosage of BCAAs should I take?
You should aim to take 3-5g dosages of BCAAs to yield optimal benefits.
What are the side effects of BCAAs?
Taking BCAAs is generally considered safe, however due to a lack of research, it is not recommended to take BCAAs during pregnancy.

- Wilkinson DJ, Hossain T, Hill DS, Phillips BE, Crossland H, Williams J,… Atherton PJ. (2013). Effects of leucine and its metabolite B-hydroxy-β-methylbutyrate on human skeletal muscle protein metabolism. J Physiol 2013. 1;591(11):2911-23
- Jackman SR, Witard OC, Phil A, Wallis GA, Baar K, Tipton KD. (2017). Branched-Chain Amino Acid Ingestion Stimulates Muscle Myofibrillar Protein Synthesis following Resistance Exercise in Humans. Front Physiol. 7;8 :390, 2017
- Churchward-Venne TA1, Breen L, Di Donato DM, Hector AJ, Mitchell CJ, Moore DR, Stellingwerff T, Phillips SM. (2013) Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men: a double blind, randomized trial. Am J Clin Nutr. 2014 99(2):276-86
- Mitchel CJ, Churchward-Venne TA, Cameron-Smith D, Phillips SM (2015). What is the relationship between the acute muscle protein synthesis response and changes in muscle mass? J Appl Physiol. (2015). 118: 495-497
- Jackman SR, Witard OC, Jeukendrup AE, Tipton KD. (2010) Branched-chain amino acid ingestion can ameliorate soreness from eccentric exercise. Med Sci Sports Exerc. 42(5):962-70, 2010.
- Van Dusseldorp TA, Escobar KA, Johnson KE, Stratton T, Moriarty T, Cole N… Mermier CM. (2018). Effect of branch-chain amino acid supplementation on recovery following acute eccentric exercise. 1;10
- Cinteneo HP, Arent MA, Antonia J, Arent SM. (2018). Effects of protein supplementation on performance and recovery in resistance and endurance training. Front Nutr. 11;5:83
- Gorissen, S. H., Crombag, J. J., Senden, J. M., Waterval, W. H., Bierau, J., Verdijk, L. B., & van Loon, L. J. (2018). Protein content and amino acid composition of commercially available plant-based protein isolates. Amino acids, 50(12), 1685-1695.
- Matu J, Gonzalez JT, Isopoglou T, Duckworth L, Deighton K. (2018). The effects of hypoxia on hunger perceptions, appetite- related hormone concentrations and energy intake: A systematic review and meta-analysis. Appetite (2018). 125:98-108
- Atherton PJ, Etheridge T, Watt PW, Wilkinson D, Selby A, Rankin D…Rennie MJ. (2010). Muscle full effect after oral protein: time-dependent concordance and discordance between muscle protein synthesis and mTORC1 signaling. The American Journal of Clinical Nutrition. 2010. 92(5): 1080-8
- Blomstrand, E., Hassmén, P., Ek, S., Ekblom, B., & Newsholme, E. A. (1997). Influence of ingesting a solution of branched‐chain amino acids on perceived exertion during exercise. Acta Physiologica Scandinavica, 159(1), 41-49.
- Leahy, D. T., & Pintauro, S. J. (2013). Branched-chain amino acid plus glucose supplement reduces exercise-induced delayed onset muscle soreness in college-age females. ISRN nutrition, 2013.
- 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.