Supplements that contain BCAA, which stands for "branched-chain amino acid," sound like something only serious bodybuilders and fitness fanatics take. Often discussed in the context of weightlifting and building muscle [1], BCAAs can be beneficial for people who are looking to optimize their weight-training plans. If BCAAs seem intimidating or you just want to know what the heck they are, we tapped into an expert, who broke it all down and explained who could benefit from BCAAs.

What Are BCAAs?

Amino acids are the building blocks of protein and help our bodies work properly; they're crucial to metabolic function. Although our bodies make some amino acids, we have to get others from our diet. Three of the essential amino acids [2] are branched-chain amino acids (valine, leucine, and isoleucine), and animal proteins are the best sources of BCAA. Of the amino acids in animal-based proteins, such as meat, dairy, and eggs, about 25 percent are BCAAs, explained Pamela S. Hinton, PhD, associate professor of nutrition and exercise physiology at the University of Missouri.

How Do BCAAs Help in Fitness?

Protein itself isn't a major source of energy during exercise, Dr. Hinton told POPSUGAR. Instead, your body uses carbohydrates and fat — the only time your body gets fuel from protein is during ultraendurance training, but even then, it's only a small amount. But BCAAs in particular could help with building muscle mass.

"What makes BCAA potentially beneficial for increasing skeletal muscle mass is the BCAA, in particular leucine, 'turns on' protein synthesis," she told POPSUGAR. Protein synthesis is the process by which cells generate new proteins. "There is some evidence that 10 to 15 grams per day might produce greater gains in muscle mass with resistance exercise," she added.

BCAAs have also been marketed as a supplement that can aid in muscle recovery and relieve muscle soreness. However, a 2017 review [3] that examined studies on how BCAA supplements alleviate muscle damage found that using BCAA supplementation to reduce or prevent muscle damage from high-intensity exercise "seems to be poor." The one study that found a positive correlation only examined six participants.

"The existing evidence from quality, double-blind, placebo-controlled experiments is limited to a few studies with relatively small sample sizes," Dr. Hinton said. "Likewise, muscle damage has not been evaluated directly; rather, blood markers of damage are used as indicators.

Despite these limitations, she said BCAAs could help with muscle damage under the right conditions: if a supplementation of 0.2 grams per kilogram of bodyweight is taken seven days before the damaging exercise and continued for 10 days. Even so, BCAAs appear to be more effective at limiting low to moderate exercise-induced muscle damage rather than severe damage.

So, Should I Take BCAA Supplements?

"Should" may be too strong of a word, Dr. Hinton said, but they do have their place. "BCAA supplements might be beneficial for muscle growth, but these same amino acids could also be consumed in foods," she told POPSUGAR.

If you are interested in supplementing your fitness regimen [4] with BCAAs, Dr. Hinton said that more isn't always better; 20 grams of BCAAs split into several doses throughout the day is safe. But if you're eating plenty of BCAA-rich food, such as beef, chicken, fish, soy, eggs, and beans, you may not need a supplement at all. It's ultimately a personal decision — just remember that you should be eating 0.5 to 0.8 grams of protein per pound of bodyweight for optimal muscle-mass gains [5].