Supplement Profile: Branch Chain Amino Acids

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Branch chain amino acids (BCAAs) consist of three of the twenty amino acids (building blocks of protein) and three of the nine essential amino acids. Essential amino acids must be ingested because our bodies are unable to make them. BCAAs occur naturally in all complete protein sources with amounts varying depending on the source. The highest amounts occur in whey protein, dairy, beef, and salmon. These three amino acids: leucine, isoleucine, and valine are commonly isolated and used as supplements. Claims of increased protein synthesis, reduced time to fatigue, and increased rates of fat loss all are reasons for supplementation. Does research back these claims? Read on to find out!


Positive Claims:

Claim: Increased fat loss.

  • Research: Some studies have noted a slight increase in fat usage with BCAA supplementation. Researchers think that this may be caused by the ability of BCAAs to preserve glucose stores within the muscle. These results are minor and do not warrant BCAA supplementation for fat loss purposes.


Claim: Increased muscle growth and repair.

  • Research: Muscle growth and repair seem to be the most significant benefit of BCAA supplementation. One of the BCAAs; Leucine, is able to “turn on” a pathway that increases protein synthesis. Increases in protein synthesis can result in muscle growth or maintenance of muscle. For this reason, BCAAs are beneficial for individuals looking to gain lean mass or maintain lean mass during exercise that may lead to muscle breakdown (long distance endurance events).


Claim: Reduced fatigue.

  • Research: Reduced time to fatigue has been found to occur with BCAA supplementation in untrained or lightly trained individuals. Highly trained athletes do not see the same reductions in time to fatigue.


Negatives Claims:

  • No concerns exist with BCAA supplementation in a healthy population.



BCAAs tend to occur in a 2: 1: 1 gram ratio (leucine: isoleucine: valine). Since research shows approximately 3g of leucine maximally stimulates protein synthesis, it’s suggested that approximately 6-8 grams is optimal per serving. I take BCAAs between meals since they have been shown to stimulate protein synthesis between whole food meals. I also try to time my meals and BCAA intake so that I have a serving of BCAAs before, during or after my workout for improved recovery and muscle growth. For more information on timing of BCAAs and/or protein during the course of your day, click here.


If building/maintaining muscle tissue is your main goal, BCAA supplementation does appear to be beneficial. If your overall protein intake is low, essential amino acids (EAAs) are a better choice since you may be deficient in the six other amino acids your body can’t make.

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