Branched-chain amino acid (BCAA)

Branched-chain amino acid (BCAA)

Branched Chain Amino Acids (BCAAs) refers to three amino acids: leucine, isoleucine, and valine.

For people with low dietary protein intake, BCAA supplementation can promote muscle protein synthesis and increase muscle growth over time. Supplementation can also be used to prevent fatigue in novice athletes.

Leucine plays an important role in muscle protein synthesis, while isoleucine induces glucose uptake into cells. Further research is needed to determine valine’s role in a BCAA supplement.

Supplementing BCAAs prevents a serum decline in BCAAs, which occurs during exercise. A serum decline would normally cause a tryptophan influx into the brain, followed by serotonin production, which causes fatigue.

BCAAs are important to ingest on a daily basis, but many protein sources, such as meat and eggs, already provide BCAAs. Supplementation is unnecessary for people with a sufficiently high protein intake (1-1.5g per kg of bodyweight a day or more).

How to Take

The three BCAAs are leucine, isoleucine, and valine. They’re considered the most anabolic of the nine EAAs and have therefore been marketed as a sports supplement. It is however possible that only leucine is especially anabolic, and that leucine taken alone is actually more anabolic than leucine taken with isoleucine and valine, due to competition for both absorption in the gut and entry into muscle tissue.

The standard leucine dosage is 2–10g. The standard dosage for isoleucine is 48–72 mg per kilogram of bodyweight, assuming a non-obese person. A combination dose is 20 g of combined BCAAs, with a balanced ratio of leucine and isoleucine.

Isoleucine is used for increasing glucose uptake into cells, while leucine is used to improve muscle protein synthesis.

BCAA supplementation is not necessary if enough BCAAs are provided through the diet. Further research is needed to determine valine’s optimal dosage and reason for supplementation.

Research analysis led by Kamal Patel