For athletes and fitness enthusiasts, Branched Chain Amino Acids (BCAAs) are often an integral part of training. BCAAs are proteinogenic (protein creating) amino acids named for their branched structure. Specifically, the branched chain amino acids are Leucine, Isoleucine and Valine. These amino acids are gaining notoriety in the world of sports nutrition.
BCAA supplementation has been reported to decrease exercise induced muscle degradation that may occur during intense training by stimulating protein synthesis.  Research also suggests that it may help delay the onset of fatigue as well as support and strengthen the immune system.  Dietary sources are meat, dairy and legumes. In addition to a healthy diet, there are BCAA supplements that can be used for additional supplementation.
 Kreider, RB, Wilborn, CD, Taylor, L, Campbell, B, Almada, AL, Collins, R, Cooke, M, Earnest, CP, Greenwood, M, Kalman, DS, Kerksick, CM, Kleiner, SM, Leutholtz, B, Lopez, H, Lowery, LM, Mendel, R, Smith, A, Spano, M, Wildman, R, Willoughby, DS, Ziegenfuss, TN, Antonio, J. “ISSN Exercise & Sport Nutrition Review: Research and Recommendations.” J.of the Int. Soc. Sports Nut. 7:7 1-43, 2010.
 Biomstrand, E, Eliasson, J, Karlson, HK, Konnke, R. “Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise. J of Nutrition 136 (1 suppl) (2006): 269S-273S.
 Negro, M, Giardina, S., Marzani, B, Marzatico, F. “Branched-chain amino acid supplementation does not enhance athletic performance but affects muscle recovery and the immune system.” J of Sports Phy Fit 48:3 (2008): 347-351.