BCAAs are essential amino acids. The three BCAAs are leucine, isoleucine, and valine.
The body uses amino acids to make proteins, which are the building blocks of every cell, tissue, and organ. Amino acids and proteins also play a crucial role in metabolism.
There are 20 amino acids, of which nine are essential. The body cannot make essential amino acids, so a person needs to get them from their diet.
In this article, we discuss some potential health benefits of BCAAs. We also describe sources of these amino acids and possible risks.
BCAA supplements may help improve exercise performance.
Taking BCAA supplements may help reduce exercise fatigue and improve endurance.
In a 2013 study involving 26 college-age males, researchers randomly assigned participants to groups. One group took a BCAA supplement and the other a placebo. The team then asked the participants to cycle to exhaustion.
The researchers found that during the cycling, blood levels of serotonin were lower in the participants who took BCAA. Serotonin is an important brain chemical that also plays a role in exercise fatigue.
BCAA supplementation also improved energy metabolism and lowered levels of substances that indicate muscle damage, such as creatine kinase and lactate dehydrogenase.
The researchers concluded that BCAA can improve exercise performance.
Lean muscle mass
According to the authors of a study from 2009, BCAA supplementation can also help improve lean mass and decrease the percentage of body fat.
The study involved 36 strength-trained males who had practiced resistance training for at least 2 years.
The participants underwent an 8-week resistance-training program, and the researchers randomly assigned them to groups. Each received either:
- 14 grams (g) of BCAAs
- 28 g of whey protein
- 28 g of carbohydrates from a sports drink
The researchers found that the participants who took BCAAs had a more significant decrease in body fat and a greater increase in lean mass, compared with the other groups.
Muscle mass during illness
BCAAs, particularly leucine, may help maintain muscle mass in people with chronic conditions.
According to a 2012 review, a variety of illnesses can affect protein synthesis, which can lead to a loss of body protein and skeletal muscle mass.
The authors found evidence that a high-protein diet that provides additional leucine can help maintain muscle mass in people with chronic diseases such as cancer.
A 2017 systematic review found some evidence that BCAA supplementation can help reduce the muscle damage that occurs during high-intensity exercise. However, the authors caution that the evidence base was limited to one small study and that confirming these findings will require more research.
Results of a small study from 2013 show that adult male participants who took a BCAA supplement during exercise had lower blood levels of substances that indicate muscle damage than those who took a placebo.
The researchers concluded that BCAA supplementation may reduce muscle damage after endurance exercises.
Consecutive-day sprint performance
A 2015 study investigated the effects of combined BCAA and arginine supplementation on intermittent sprint performance over 2 consecutive days. Arginine is another type of amino acid.
The study involved 7 females and 15 males who had competed at a national or international level in handball. The participants played simulated handball games over 2 consecutive days.
The researchers found that intermittent sprint performance on the second day was significantly better in the athletes who had taken the supplement, compared with those who had taken the placebo.
The authors concluded that their results could have “significant practical applications” for athletes who have to compete on consecutive days.
BCAA supplementation may benefit people with liver disease.
In a 2017 study, researchers randomly assigned participants with advanced liver cirrhosis into groups. For at least 6 months, each group consumed either BCAAs daily or a diet without BCAAs.
Over 2 years, Model for End-Stage Liver Disease (MELD) test scores improved significantly among participants who consumed BCAAs, compared with those who did not.
Doctors calculate MELD scores by measuring levels of certain substances in the blood, such as creatinine and bilirubin. They use the resulting score to help determine how close a person is to having liver failure.
The authors concluded that long-term BCAA supplementation has beneficial effects in people with advanced liver cirrhosis and that understanding these effects will require further research.
Another study from 2017 also found that BCCA supplementation improved low muscle strength among people with liver cirrhosis. The researchers assessed muscle strength by testing each participant’s hand grip.