Branched-chain amino acids (BCAAs) play an important role in the building and repairing of muscles. They get their name from their chemical structure, which also affects the way the body uses them. The three BCAAs are leucine, valine, and isoleucine. They comprise three of the nine essential amino acids, considered essential because the body cannot make them but must get them from food.
Most amino acids are metabolized or broken down in the liver. BCAAs are mostly metabolized in muscle tissue. That makes BCAA supplements attractive to athletes and bodybuilders, but research doesn’t offer strong evidence for the use of BCAAs to increase muscle mass. BCAA supplements may be no better for muscle growth and recovery than BCAAs from dietary sources.
An inability to metabolize BCAAs causes several serious conditions. Treatment sometimes involves reducing protein intake.
Health Benefits
Since scientists discovered branched-chain amino acids in the mid-1800s, they have studied them intensively. They know that BCAAs are important for many body functions, but there is much more for science to investigate.
Some research supports these health benefits of BCAAs:
Muscle Building
Several studies suggest that BCAA supplements may increase muscle mass and strength during training. The studies were short-term and did not show that supplementing with BCAAs is superior to getting them from dietary sources.
Muscle Recovery
Some studies suggest that BCAAs may ease soreness and help with recovery following exercise. The effect may not be significant enough to warrant the use of supplements.
Cirrhosis of the Liver
People with cirrhosis of the liver often have low levels of BCAAs, and supplementation may help. Adding BCAAs does not always improve symptoms, however, and those with cirrhosis should use BCAAs only under a doctor’s supervision.
Tardive Dyskinesia
Those who take certain drugs may have a condition called tardive dyskinesia that causes uncontrolled movements. Some antipsychotic drugs and some anti-nausea drugs can cause this condition. Some evidence indicates that supplements of BCAAs can reduce symptoms.
