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The term Branched-chain amino acids or BCAAs sometimes refers to the amino acids having aliphatic side-chains that are non-linear. These are L-leucine, L-isoleucine and L-valine. These have a particular molecular structure that gives them their name. The combination of these three essential amino acids make up approximately 1/3 of skeletal muscle in the human body, and play an important role in protein synthesis. BCAAs are currently used clinically to aid in the recovery of burn victims, as well as for supplementation for strength athletes.[1] These amino acids, L-leucine in particular, help increase work capacity by stimulating production of insulin. BCAAs are burned as fuel during highly intense training and at the end of long-distance events; during these times the body recruits protein for as much as 20% of its energy needs. [2]


  1. various (n.d.). Branched-chain Amino Acids. Wikipedia. Retrieved on 2008-09-19.
  2. Gastelu, Dan; Hatfield, Frederick C (2006). Specialist in Performance Nutrition: The Complete Guide. Carpenteria, CA: ISSA, 17. 
Amino Acids
Amino Acids AlanineArginineAsparagineAspartateCysteineGlutamateGlutamineGlycineHistidineIsoleucineLeucineLysineMethioninePhenylalanineProlineSerineThreonineTryptophanTyrosineValine
Essential Amino Acids IsoleucineLeucineLysineMethioninePhenylalanineThreonineTryptophanValine
Nonessential Amino Acids AlanineArginineAsparagineAspartateCysteineGlutamateGlutamineGlycineHistidineProlineSerineTyrosine
BCAAs IsoleucineLeucineValine