Supplemental dietary leucine and the skeletal muscle anabolic response to essential amino acids

Nutr Rev. 2011 Sep;69(9):550-7. doi: 10.1111/j.1753-4887.2011.00420.x.


Skeletal muscle protein synthesis (MPS) is regulated by a number of dietary factors, to include essential amino acids (EAAs). Leucine, a branched-chain amino acid, has been identified as a stimulator of MPS in many cell culture and animal studies. However, whether supplemental leucine exerts a unique stimulatory effect, as compared to other EAAs, on muscle anabolism in humans has not been clearly demonstrated. A recent study found no improvement in resting MPS in adults who consumed a 10 g EAA supplement providing added leucine (3.5 g leucine) when compared to a control 10 g EAA supplement (1.8 g leucine). These findings suggest that added leucine is unnecessary for the stimulation of MPS when sufficient EAAs are provided; however, the study of supplemental leucine during conditions such as endurance exercise, caloric deprivation, and ageing may be warranted.

Publication types

  • Review

MeSH terms

  • Amino Acids, Essential / metabolism*
  • Animals
  • Dietary Supplements*
  • Humans
  • Leucine / administration & dosage
  • Leucine / metabolism*
  • Muscle Proteins / biosynthesis*
  • Muscle, Skeletal / metabolism*


  • Amino Acids, Essential
  • Muscle Proteins
  • Leucine