Taking BCAA supplements can prevent the breakdown of protein in certain populations with muscle wasting.īCAAs may offer health benefits for people with cirrhosis, a chronic disease in which the liver does not function properly. This may improve health outcomes and quality of living in certain populations, such as older adults and those with conditions like cancer ( 23, 24).

Several studies support the use of BCAA supplements for inhibiting muscle protein breakdown. Therefore, it’s important that the BCAAs and other essential amino acids are replaced during times of muscle wasting to halt it or to slow its progression. They account for 40% to 45% of the total amino acids required by your body ( 21, 22). In humans, BCAAs account for 35% of the essential amino acids found in muscle proteins. Muscle wasting is a sign of malnutrition and occurs with chronic infections, cancer, periods of fasting, and as a natural part of the aging process ( 19, 20). Muscle wasting or breakdown occurs when protein breakdown exceeds muscle protein synthesis. The balance between muscle protein breakdown and synthesis determines the amount of protein in muscle ( 18). Muscle proteins are constantly broken down and rebuilt (synthesized). summaryīCAAs can alter levels of certain chemicals in the brain, such as serotonin, which may be useful in decreasing exercise-induced fatigue.īCAAs can help prevent muscle wasting or breakdown. In two studies, participants who supplemented with BCAAs experienced a reduction in central fatigue, resulting in improved athletic performance ( 16, 17). In your brain, tryptophan is converted to serotonin, a brain chemical that is thought to contribute to the development of fatigue during exercise ( 14, 15). When blood levels of BCAAs decline, levels of the essential amino acid tryptophan in your brain increase ( 14). Your muscles use BCAAs during exercise, causing levels in your blood to decrease. How quickly you tire depends on several factors, including exercise intensity and duration, environmental conditions, and your nutrition and fitness level ( 13). Just as BCAAs may help decrease muscle soreness from exercise, they may also help reduce exercise-induced fatigue.Įveryone experiences fatigue and exhaustion from exercise at some point. Supplementing with BCAAs may decrease muscle soreness by reducing damage in exercised muscles. Therefore, supplementing with BCAAs, especially before exercise, may speed up recovery time ( 12). In one 2010 study, people who supplemented with BCAAs before a squat exercise experienced reduced DOMS and muscle fatigue compared to the placebo group ( 11). Several studies show that BCAAs decrease protein breakdown during exercise and decrease levels of creatine kinase, which is an indicator of muscle damage ( 9, 10). Meanwhile, other research suggests that it may actually be related to the connective tissue associated with the muscle rather than the actual muscle itself ( 8).īCAAs have been shown to decrease muscle damage, which may help reduce the length and severity of DOMS. While the exact cause of DOMS is not clearly understood, one theory is that it’s the result of tiny tears in the muscles after exercise ( 8). This soreness is called delayed onset muscle soreness (DOMS), which develops 12 to 24 hours after exercise and can last up to 72 hours ( 7). It’s not uncommon to feel sore a day or two after a workout, especially if your exercise routine is new. Some research suggests BCAAs can help decrease muscle soreness after a workout. However, your muscles require all of the essential amino acids for the best results. summaryīCAAs play an important role in building muscle. Therefore, while BCAAs can increase muscle protein synthesis, they can’t do so maximally without the other essential amino acids, such as those found in whey protein or other complete protein sources ( 5, 6). Whey protein contains all of the essential amino acids needed to build muscle. That being said, this increase in muscle protein synthesis is approximately 50% less than what was observed in other older studies where people consumed a whey protein shake containing a similar amount of BCAAs ( 3, 4). In one study, people who consumed a drink with 5.6 grams (g) of BCAAs after their resistance workout had a 22% greater increase in muscle protein synthesis compared to those who consumed a placebo drink ( 2). The BCAA leucine activates a certain pathway in the body that stimulates muscle protein synthesis, which is the process of making muscle ( 1).

One of the most popular uses of BCAAs is to increase muscle growth.

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