Arginine

• Arginine, a popular supplement with muscle-builders, is an essential amino acid that may increase the production of growth hormones. Foods that contain arginine include nuts, seeds, peas and chocolate. A side effect to this amino acid is the possibility that it may promote herpes virus growth.
  
  

Phenylalanine

• Phenylalanine comes in two forms: L-phenylalanine to treat depression, and D-phenylalanine to control chronic pain. If you have high blood pressure, avoid taking L-phenylalanine. Other side effects include a stimulant effect that can contribute to insomnia and anxiety. If you have the genetic disorder phenylketonuria, do not take phenylalanine.
  
  

Tryptophan

• Tryptophan is found in nuts, grains, beans, legumes and turkey. The one side effect tied to tryptophan is a rare blood abnormality that leads to death when tryptophan is taken in supplement form.
  
  

Taurine

• The amino acid taurine is found in high levels in fish, and has been used to treat epilepsy. Taking taurine in high doses may cause depression.
  
  

Single Amino Acids

• Taking single amino acids may cause an imbalance in other amino acids over an extended period of time. Taking a supplement that contains a balance of amino acids may help to prevent this from occurring.