Branched-chain amino acids (BCAAs)

Source: U.S. Department of Health & Human Services, National Institutes of Health, Office of Dietary Supplements (2017).


INGREDIENT	Branched-chain amino acids (BCAAs) The amino acids leucine, isoleucine, and valine are known as BCAAs. Animal foods, like meat, fish, and milk, contain BCAAs. Your muscles can use these three amino acids to provide energy during exercise. Leucine might also help build muscle.

DOES IT WORK?	There’s little evidence that BCAA supplements improve performance in endurance activities like distance running. BCAA supplements might help increase your muscle size and strength together with a weight-training program. But it isn’t clear whether taking BCAA supplements will help you build more muscle than just eating enough high-quality protein foods.

IS IT SAFE?	A nutritious diet with enough protein can easily provide 10 to 20 grams a day of the BCAAs. Taking up to another 20 grams a day of BCAAs in supplements seems to be safe.

BOTTOM LINE	There’s not much scientific evidence to support taking BCAA supplements to improve performance, build muscle, or help tired and sore muscles to recover after exercise. Eating foods containing protein automatically increases your intake of BCAAs.

REMARK	Many performance supplements in the marketplace contain more than one ingredient, and ingredients can work differently when they’re combined. Because most ingredient combinations have not been studied, it is not known how effective or safe they are in improving performance.