Glycine is another conditionally essential amino acid found in plant and animal protein. Chemically, glycine is the most simple and most ubiquitous (seemingly present everywhere) of all of the amino acids.
It combines with many toxic substances and converts them to harmless forms, which are then excreted from the body. Glycine has a calming effect on the brain. It may also be a growth hormone releaser. (Along with cysteine and glutamic acid, glycine is also a component of glutathione.)
In a study of the Japanese drug, Stronger Neo-Minophagen C, a drug containing glycine, glycyrrhizin, and cysteine, which is said to be protective against chronic cadmium toxicity, Shaikh et al. (1999b) concluded that the reported beneficial effects of Stronger Neo-Minophagen C were from glycine. Glycine appeared to reduce the oxidative stress of chronic cadmium toxicity. However, as of spring 2002, Stonger Neo-Minophagen C was not available in the United States (www.fda.gov).