Supplement Forms/Alternate Names:

  • BCAAs, leucine, isoleucine, valine

Branched chain amino acids (BCCAs) refers to a group of proteins with a branch-like structure. These proteins are used to rebuild muscle. BCCAs have been used to ease muscle soreness and improve muscle function. They can be taken as a pill or powder. They can also be injected into the bloodstream by a healthcare provider.

1 to 5 grams once daily.

What Research Shows

May Be Effective

  • Hepatic encephalopathy—may reduce symptoms B1
  • Muscle soreness—may ease muscle pain after vigorous exercise E1-E3

Not Enough Data to Assess

  • Bipolar disorder A1
  • Liver cancer C1, C2
  • Liver transplant support D1
  • Porto-systemic encephalopathy F1

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe to take branched chain amino acids in small doses for a short time, but nausea and vomiting are possible. It may also increase the risk of diabetes. G1 Not enough studies have been done to say whether it is safe to take for a long period. It is also not known whether it is safe to take by women who are pregnant or breastfeeding.


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse.

Revision Information

  • Reviewer: EBSCO NAT Review Board Eric Hurwitz, DC
  • Review Date: 12/2019 -
  • Update Date: 12/03/2019 -