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.
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:
Several studies suggest that BCAAs 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.
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.
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.
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.
Branched-chain amino acid supplements are considered safe when taken in proper doses for short periods of time. As far as researchers have observed, BCAAs cause very few adverse effects. BCAAs may interact with medications, including thyroid hormones, drugs for Parkinson's, and medicines for diabetes.
High Blood Pressure
One study has found that high concentrations of BCAAs are associated with an increased risk of high blood pressure in middle-aged men and women. This study had some limitations, so the topic needs further study.
Research indicates that limiting amino acids before surgery could reduce the risk of complications. In particular, the risk of stroke and heart attack may be lessened.
Amounts and Dosage
A typical BCAA dosage for muscle enhancement is up to 20 grams a day taken in divided doses. This amount appears to be safe. If you are taking BCAAs for a purpose other than muscle growth, your doctor will specify the dosage.
You can get BCAAS from animal proteins such as meat, fish, eggs, milk, and poultry. You can also get them from plant-based foods when combined to offer all the essential amino acids. The body uses BCAAs found in food efficiently.