For decades, athletes (especially bodybuilders) have used amino-acid supplements as ergogenic aids (something that increases muscular work capacity) and to help meet athletic goals. As might be expected, certain individual amino acids or combinations work better than others.
Essential Amino Acids
An essential amino acid is one that your body needs but does not manufacture; you must obtain it through diet. When essential amino acids are present in the diet, the body is able to make an adequate supply of nonessential amino acids (the ones your body manufactures).
One small study finds that when people take 6 grams of essential amino acids in the right proportions one or two hours after resistance training, the result is an increase in muscle protein synthesis. When they’re taken before weight training, the increase in muscle protein synthesis is even greater. When used in the right proportions and taken at the right times, essential amino acids can significantly increase muscle protein synthesis.
Contrary to the current position of conventional nutrition science, researchers also find that there is no additional benefit gained by including nonessential amino acids. Likewise, the amino acid blend does not require any carbohydrates to exert its effects on muscle protein synthesis.
Branched-Chain Amino Acids
The branched-chain amino acids (BCAAs)—leucine, isoleucine, and valine—maintain muscle tissue by preventing breakdown during exercise. They’re commonly used by athletes to ensure a quick recovery after a workout. BCAAs also supply energy to the heart and skeletal muscles.
Several studies suggest that supplementation with BCAAs has an ergogenic effect in people who exercise, including an increase in lean body mass. Research also shows that highly trained athletes using BCAAs are able to avoid the significant loss in body weight and decrease in peak power experienced by those not taking them. Even untrained individuals using BCAAs experience a significant increase in fat-free mass and grip strength.
Considered a semiessential amino acid (your body makes it to a certain extent, but it becomes essential under some circumstances, like following an injury), arginine has several important roles in your body. Its most popular use as an ergogenic supplement is its ability to augment nitric oxide levels, possibly helping to enhance your performance. Nitric oxide increases blood flow to working muscles, which in turn leads to increased oxygen transport and delivery of fuel to skeletal muscle. Supplemental arginine is thought to augment nitric oxide production, leading to an increase in blood flow.
There is no magic pill that works without exercise to promote muscle growth and improve performance. But when combined with a healthful diet, amino acids may help you achieve your sports-nutrition goals.