BCAAs are essential amino acids that bodybuilders and athletes use to increase power output, reduce fatigue, and improve fat loss. However, excessive BCAA usage can have negative side effects, such as increasing the risk for type 2 diabetes and other conditions. Read on for further details on the potential effects of BCAA and their correct dosage. What Are BCAAs?
There are three BCAAs: leucine , isoleucine, and valine, which are all essential amino acids – not produced by the body but needed for survival [ 1 , 2 ].
BCAAs are the largest collection of amino acids in the body, accounting for up to 35% of muscle proteins . These amino acids (especially leucine) stimulate protein production in the muscles, possibly helping with muscle building and recover [ 1 , 3 , 4 ].
They also seem to promote sugar storage in the muscles. In animal studies, BCAAs (especially isoleucine) promoted blood glucose uptake into the muscles while blocking muscle carbohydrate (glycogen) breakdown [ 5 , 6 ].
Normally, BCAAs are excreted rapidly. BCAA intermediates can be toxic at high concentrations, so functional BCAA breakdown is vital. Because BCAAs are broken down in the muscle rather than in the liver, they are thought to help produce energy during exercise [ 1 , 2 , 7 ].
BCAA formulas have been on the market since 1996, mainly for treating liver diseases such as cirrhosis and hypoalbuminemia [ 8 ].
Nowadays, BCAAs are mainly used by bodybuilders for exercise purposes, to increase energy, and boost protein synthesis (especially leucine) [ 1 ]. Snapshot
Essential amino acids
Approved for nitrogen loss
May help recover from exercise and increase body lean mass
May help with liver cirrhosis and its complications
Unclear effects on exercise performance
Excessive supplementation may trigger type 2 diabetes and ALS
May cause high ammonia levels
May interfere with the uptake of other essential amino acids
Not recommended in people with insulin resistance, McArdle’s disease, and maple syrup urine disease
An injectable 4% BCAA formulation (BranchAmin) is approved by the FDA as a nitrogen source in people with severe nitrogen loss due to poor protein absorption or septic shock [ 9 ]. Possibly Effective for:
1) Exercise Recovery
BCAA supplements taken before and after exercise reduced exercise-induced muscle soreness and damage in 8 clinical trials on 134 people. This may speed up exercise recovery while preventing injuries [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ].
However, they were of little or no effectiveness in trials on 21 older volunteers performing a 2-day trail in the mountains and 30 well-trained men recovering from intense weight training [ 18 , 19 ].Supplementing with BCAAs seems to preserve muscle proteins by both preventing their breakdown and stimulating their production [ 20 , 21 , 22 ].A meta-analysis of 8 clinical trials concluded that BCAA supplementation was better than rest alone for recovery after exercise due to its ability to reduce muscle soreness and function decline [ 23 ]. Physical Performance Decline In 2 clinical trials on 21 athletes, BCAA supplementation reduced central fatigue after intense exercise [ 24 , 25 ].In 2 clinical trials on 27 well-trained people, BCAAs prevented the decline in power output after exercise [ 26 , 15 ]. Cognitive Performance Decline The reduced central fatigue caused by BCAA supplementation preserved the ability to couple movement and spatial perception (perceptual-motor skills) after exercise in a clinical trial on 9 tennis players [ 25 ].In a trial of 12 volunteers, BCAA supplementation prevented the decline in short-term memory caused by exercise [ 27 ].In another trial on 10 soccer players, BCAA supplements reduced the decline in reaction time by 10% [ 28 ].Taken together, the evidence suggests that BCAAs may help with exercise recovery, especially by reducing muscle soreness and preserving its function. You may discuss with your doctor if you may add them to your training routine. 2) Increasing Lean Mass In a clinical trial on 36 body-builders, BCAA supplements increased lean mass better than other supplements like carbohydrates and whey protein [ 29 ].In another trial on 40 men, both low (6.25 g) and high (25 g) BCAA doses were similarly effective at promoting muscle building after exercise when supplemented with high levels (5 g) of leucine [ 30 ].In 17 resistance-trained men on a low-calorie diet, BCAA supplementation maintained weight loss while preserving muscle mass . Similarly, elite wrestlers on a low-calorie diet l ost more weight when supplemented with BCAAs in a clinical trial on 25 people [ 31 , 32 ].A high dietary consumption of BCAAs was associated with a reduced incidence of obesity in 2 observational studies on over 5,500 people [ 33 , 34 ].Supplementing with BCAAs and vitamin B6 failed to promote weight loss but reduced waist-to-hip ratio and preserved legs lean in a clinical trial on 42 overweight women [ 35 ].BCAAs may also help prevent muscle loss in people at risk. In a study on 73 functionally-limited elderly people, high BCAA levels were associated with increased lean mass (both increased muscle section and reduced fat). Supplementation improved muscle mass and strength in 2 trials on 73 people with rheumatoid arthritis and 68 people with sarcopenia [ 36 , 37 , 38 ].Although limited, the evidence suggests that BCAA supplementation may help both build muscle and lose fat. However, doing more exercise and improving your diet may be safer and more effective ways to obtain these benefits. You may discuss with your doctor if BCAAs may help as a complementary strategy. 3) Liver Damage and Complications In 3 clinical trials on almost 700 people with liver cirrhosis, supplementation with BCAA granules increased survival and quality of life . The treatment was more effective when given during the night, probably because it helped spare proteins [ 39 , 40 , 41 ].The survival rate without any detrimental event was […]