Branched-chain amino acids

background

Branched-chain amino acids (BCAAs) consist of three amino acids: leucine, isoleucine, and valine.
BCAAs may be converted to glucose and therefore may be used as an energy source during exercise. Also, some evidence suggests that BCAAs may be used in making protein during muscle repair following exercise.
BCAAs are most often used as a supplement for increased athletic performance and endurance.
Preliminary research suggests that BCAAs may be helpful for muscle atrophy associated with bed rest, neurological disorders, in particular spinocerebellar degeneration, and tardive dyskinesia. However, more research is needed to confirm this.

Related Terms

2-Amino-3-methylbutanoic acid, 2-amino-3-methylbutyric acid, 2-amino-3-methylvaleric acid, 2-amino-4-methylvaleric acid, 2-aminoisovaleric acid, (2S,3S)-2-amino-3-methylpentanoic acid, alpha-amino-beta-methylvaleric acid, alpha-aminoisocaproic acid, alpha-aminoisovaleric acid, Aminoleban®, Amino-Mel hepa® + L-valine, BCAA, hard body BCAA (MLO Products), hepatic aid, hi-test muscle octane BCAA's (Anabol Naturals), Ile, isoleucine, large neutral amino acids, Leu, leucine, L-isoleucine, L-leucine, LNAAs, L-valine, (S)-2-amino-3-methylbutanoic acid, (S)-2-amino-4-methylpentanoic acid, Val, valine.

evidence table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
 
Chronic obstructive pulmonary disease (COPD) (Grade: C)
Supplementation with BCAAs may benefit patients with chronic obstructive pulmonary disease (COPD). However, more high-quality research is needed in this area.
Enhanced athletic performance (Grade: C)
BCAAs may increase athletic performance and endurance. Further high-quality research is needed.
Hepatic encephalopathy (Grade: C)
BCAAs may serve as a treatment for hepatic encephalopathy (confusion caused by liver failure). Further high-quality research is needed.
Hepatitis (alcoholic hepatitis) (Grade: C)
BCAAs have been suggested as a treatment for hepatitis (alcoholic hepatitis). Further high-quality research is needed.
Hormone regulation (Grade: C)
BCAAs may serve to regulate hormones. In preliminary research, BCAA supplementation was shown to prevent exercise-induced decreases in human growth hormone and testosterone concentrations. Further high-quality research is needed.
Immunomodulation (Grade: C)
BCAAs may regulate immune functioning. In preliminary research, BCAA supplementation during exercise affected white blood cells and immune cytokines after exercise. Further research is needed.
Liver cancer (hepatocellular carcinoma) (Grade: C)
BCAAs may serve as a treatment for liver cancer (hepatocellular carcinoma). In preliminary research, BCAA supplementation resulted in an improvement in clinical symptoms associated with resectioning in patients with hepatocellular carcinoma. However, more clinical trials are needed that study this effect in a larger sample size.
Liver cirrhosis (Grade: C)
BCAAs may improve symptoms associated with cirrhosis of the liver (scarring of the liver and poor liver function). However, due to various methodological issues, conclusive evidence for or against BCAA supplementation for this indication is lacking. More clinical trials are needed that study this effect in a larger sample size.
Muscle atrophy (Grade: C)
BCAAs may prevent muscle atrophy (wasting) associated with prolonged bed rest. In preliminary research, BCAA supplementation during bed rest decreased nitrogen loss during short-term bed rest. More clinical trials are needed.
Neurological disorders (spinocerebellar degeneration) (Grade: C)
BCAAs may improve brain disorder symptoms. However, more clinical trials are needed.
Phenylketonuria (Grade: C)
BCAAs may improve symptoms associated with phenylketonuria (PKU; a metabolic genetic disorder). Preliminary research suggests that BCAA supplementation increased brain function in patients with PKU. More clinical trials are needed.
Tardive dyskinesia (Grade: C)
BCAAs may improve symptoms associated with tardive dyskinesia (a disorder of involuntary movements). Preliminary research provides good indication that BCAAs may be beneficial for this indication. However, more clinical trials are needed.
Total parenteral nutrition (TPN) (Grade: C)
BCAAs may provide additional support to patients on TPN. However, clinical trials with a larger sample size are still required.
Amyotrophic lateral sclerosis (ALS) (Grade: D)
ALS is a neurodegenerative disease characterized by the degeneration of motor neurons. There seemed to be a lack of an effect after BCAA supplementation, and increased death and reduced lung function. Evidence is lacking for or against the use of BCAAs in treating ALS.