Branched-Chain Amino Acids and Workouts
By Robert Silverman, DC, DACBN, DCBCN, MS, CCN, CNS, CSCS, CIISN, CKTP, CES, HKC, FAKTR
Branched-chain amino acids are often recommended as a supplement for building muscles, helping you exercise harder and longer, and aiding recovery from training. They’re a powerful tool for athletes and bodybuilders—and anyone who wants to have more effective workouts.
Let’s start by understanding what branched-chain amino acids (BCAA) are. Amino acids are the building blocks of protein in your body. You need protein to make blood, muscles, bones, cartilage, skin, and all the other parts of your body, including your hair and nails. You need protein for normal growth and repair and to make the thousands of hormones, enzymes, neurotransmitters, and other natural body chemicals you need to stay alive. To make all these different proteins, your body needs just nine essential amino acids—the building blocks that can’t be made by your body and must come from your food. The essential nine are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Your body can produce the five nonessential amino acids—alanine, asparagine, aspartic acid, glutamic acid, and serine—by itself, without getting them from food. Then there are the conditional amino acids. These are building blocks your body can usually produce by itself, except when you’re very sick or under severe stress and need to get them from your food instead. The conditional aminos are arginine, cysteine, glutamine, tyrosine, glycine, and proline.
Within the essential amino acids group are three called BCAAs because their molecular structure includes a side chain of atoms. The four BCAAs are leucine, isoleucine, proline, and valine. But because proline is only conditionally essential, BCAA supplements don’t contain it. In the diet, BCAAs are found most abundantly in meat, dairy products, and beans and peas. In your body overall, BCAAs make up about 35 to 40 percent of all the essential amino acids. In your muscles, they make up about 14 to 18 percent of all the aminos.1
Branched-chain amino acids help build muscles
The BCAAs are the most valuable of the essential aminos for providing energy during exercise and building muscle, because they’re broken down for energy (catabolized) in your skeletal muscles, not your liver like the other amino acids.2
When you work out, especially with resistance training, you break down muscles. As you do, the muscles release some of their amino acids into your bloodstream. Most are recycled to make new proteins, but about 30 percent are lost to excretion; dietary branched-chain amino acids can help make up for that missing 30 percent, as your muscles respond to the breakdown from exercise by stimulating muscle synthesis.3 The BCAAs also help stimulate the growth of new muscles by activating the key enzymes needed for synthesizing protein after you exercise.3,4
BCAAs can also help reduce soreness following exercise from muscle breakdown. That can help reduce discomfort and fatigue and gets you back to the gym sooner.5-10
While BCAAs combined with a restricted diet may help high-level strength athletes lose body fat while retaining lean muscle mass, they probably don’t help much with weight loss for less conditioned people, even when they have been working out intensively.11-12
Why supplement with BCAAs?
Why take BCAA supplements when you can get the same amino acids from your diet or from whey supplements, which contain all the essential amino acids? As a recap, animal foods such as meat, eggs, and dairy products are high in branched-chain amino acids; they’re also found in peas and beans. Even vegans who eat no animal food can generally get enough BCAAs from their diet to meet the minimum amounts established by the IOM RDA for protein and amino acids—0.8 g/kg of body weight per day for healthy individuals ages 19 and older in the general population.13 However, for athletes and active adults, a higher protein requirement may be necessary.14
To receive the advantages of BCAAs for your muscles, supplements might be a good way to help meet your particular needs, especially on heavy workout or activity days and on recovery days. Whey supplements are a possibility, but the BCAAs in whey are bound up with the other amino acids. Your body has to digest them before they can be absorbed into your bloodstream, a process that could take several hours. Also, because whey has all of the essential amino acids, you have to consume more of it to get the desired amount of BCAAs. Concentrated BCAA supplements are a more targeted way of getting them into your system. The BCAAs in these types of supplements are already free and can be absorbed more quickly. Some athletes prefer not to use whey protein due to dietary preferences. Whey is a dairy product leftover from cheese production. For those with dietary restrictions or lifestyle preferences seeking an alternative option to whey protein drinks, athletes might consider a BCAA-only supplement along with a plant-based protein powder. Pea protein is suitable for vegetarians and vegans. As a bonus, pea protein contains prebiotic components that can help support gut bacteria.16
If you’re interested in supplementing with BCAAs, talk to your healthcare practitioner.
- Riazi R et al. The total branched-chain amino acid requirement in young healthy adult men determined by indicator amino acid oxidation by use of L-[1-13C] phenylalanine. J Nutr. 2003;133(5):1383-1389.
- Shimomura Y et al. Nutraceutical effects of branched-chain amino acids on skeletal muscle. J Nutr. 2006;136(2):529S-532S.
- Blomstrand E et al. Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise. J Nutr. 2006;136(1 Suppl):269S-273S.
- Mero A. Leucine supplementation and intensive training. Sports Med. 1999;27(6):347-58.
- Blomstrand E et al. Administration of branched-chain amino acids during sustained exercise—effects on performance and on plasma concentration of some amino acids. Eur J Appl Physiol Occup Physiol. 1991;63(2):83-88.
- Gualano AB et al. Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletion. J Sports Med Phys Fitness. 2011;51(1):82-88.
- Leahy DT et al. Branched-chain amino acid plus glucose supplement reduces exercise-induced delayed onset muscle soreness in college-age females. ISRN Nutr. 2013:921972.
- Shimomura Y et al. Branched-chain amino acid supplementation before squat exercise and delayed-onset muscle soreness. Int J Sport Nutr Exerc Metab. 2010;20(3):236-244.
- Greer BK et al. Branched-chain amino acid supplementation and indicators of muscle damage after endurance exercise. Int J Sport Nutr Exerc Metab. 2007;17(6):595-607.
- Jackman et al. Branched-chain amino acid ingestion can ameliorate soreness from eccentric exercise. Med Sci Sports Exerc. 2010;42(5):962-970.
- Stoppani J et al. Consuming a supplement containing branched-chain amino acids during a resistance-training program increases lean mass, muscle strength and fat loss. J Int Soc Sports Nutr. 2009;6(Suppl 1):P1.
- Spillane M et al. The effects of 8 weeks of heavy resistance training and branched-chain amino acid supplementation on body composition and muscle performance. J Int Soc Sports Nutr. 2013;10(Suppl 1):P25.
- Campbell B et al. International society of sports nutrition position stand: protein and exercise. J Inter Soc Sports Nutr. 2007;4:8.
- IOM. Dietary Reference Intakes for Energy, Carbohydrate. Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2002/2005).
- Babault N et al. Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, placebo-controlled clinical trial vs. whey protein. J Int Soc Sports Nutr. 2015;12(1):3.
- Dahl WJ et al. Review of the health benefits of peas (Pisum sativum L.) Br J Nutr. 2012;108:S3-10.
Dr. Silverman is a paid consultant and guest writer for Metagenics.