What are Amino Acids?
Amino acids are organic compounds that combine to form proteins. Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids to make proteins to help the body: Break down food, Grow, Repair body tissue, Perform many other body functions. Amino acids can also be used as a source of energy by the body.
Amino acids are the structural elements from which proteins are built. When amino acids bond to each other, it is done in the form of an amide , making a connection which is called a peptide linkage. This can be illustrated with the two simplest amino acids, glycine and alanine.
According to Tillery, et al., the human body can synthesize all of the amino acids necessary to build proteins except for the ten called the “essential amino acids”, indicated by asterisks in the amino acid illustrations. An adequate diet must contain these essential amino acids.
Amino acid supplementation and exercise performance
Amino acids are theorized to enhance performance in a variety of ways, such as increasing the secretion of anabolic hormones, modifying fuel use during exercise, preventing adverse effects of overtraining, and preventing mental fatigue. The following discussion highlights research regarding the ergogenic effects of individual amino acids, various combinations of amino acids, and several special protein dietary supplements.
Branched chain amino acids (BCAA)
“BCAA supplementation has been studied for its effects on various types of exercise performance, including ratings of perceived exertion (RPE) during exercise and mental performance following exercise.”
In general, the findings are equivocal, as are the conclusions from several recent reviews. One investigator concluded that BCAA supplementation reduces RPE and mental fatigue during prolonged exercise and improves cognitive performance after exercise, and also suggests that in some situations BCAA supplementation may improve physical performance, such as during exercise in the heat or in actual competitive races where central fatigue may be more pronounced than in laboratory experiments. However, other reviewers conclude that most studies show no effects of BCAA supplementation on performance, such as prevention of fatigue during prolonged exercise two recent studies support these conclusions. Watson and others reported no beneficial effects of BCAA supplementation, consumed before and during prolonged cycling to exhaustion at 50 percent VO2max in the heat, on performance time, heart rate, and core or skin temperature. Cheuvront and others  reported similar findings with subjects exercising in the heat, noting no significant effect of BCAA supplementation on time-trial performance, cognitive performance, mood, perceived exertion, or perceived thermal comfort. Although current research does not support an ergogenic effect of BCAA supplementation, most investigators recommend additional research.
“In strength athletes, amino acid supplementation has been proposed to increase the availability of essential amino acids, enhance anabolic processes promoting tissue accretion, and accelerate the rate of recovery during training.”
“In endurance athletes, amino acid supplementation has been proposed to improve physiological and psychological responses during endurance exercise and training.”
Safety and Legality
Low-dose amino acid supplementation: no effects on serum human growth hormone and insulin in male weightlifters.
Using a double-blind, crossover protocol, we studied the possible effects of a 4-day combined L-arginine, L-ornithine, and L-lysine supplementation (each 2 g/day, divided into two daily doses) on 24-hr level of serum human growth hormone (hGH) and insulin in 11 competitive weightlifters, ages 19 to 35 yrs. Three similar daily hGH peaks, seemingly preceded by a decrease in serum insulin concentration, were found during both amino acid and placebo supplementation. Supplementation did not affect the physiological variation of serum hGH concentration (treatment and treatment x time interaction: p = 0.43-0.55). Analogously, serum insulin levels were not higher after amino acid supplementation. Therefore the ergogenic value of low-dose oral amino acid supplementation in increasing hGH or insulin secretion seems questionable.
Consumption of high-protein diets (2.8 g protein/kg or less) by well-trained athletes does not appear to impair renal function, as indicated by various measures of renal function. However, certain individuals should be concerned with the protein content in their diet, such as those with diabetes mellitus predisposed to kidney disease, and those prone to kidney stones. Most amino acid supplements are safe in recommended dosages, but may interfere with protein metabolism if consumed in excess. Use of amino acid supplements is not prohibited by the World Anti-Doping Agency (WADA).
“Amino acids are biologically important organic compounds containing amine (-NH2) and carboxyl (-COOH) functional groups, along with a side-chain (R group) specific to each amino acid. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen, though other elements are found in the side-chains of certain amino acids. About 500 amino acids are known (though only 20 appear in the genetic code) and can be classified in many ways. They can be classified according to the core structural functional groups’ locations as alpha- (α-), beta- (β-), gamma- (γ-) or delta- (δ-) amino acids; other categories relate to polarity, pH level, and side-chain group type (aliphatic, acyclic, aromatic, containing hydroxyl or sulfur, etc.). In the form of proteins, amino acids comprise the second-largest component (water is the largest) of human muscles, cells and other tissues. Outside proteins, amino acids perform critical roles in processes such as neurotransmitter transport and biosynthesis.”