Glycine is, structurally, the simplest amino acid that has been discovered. It was one of the earliest amino acids to be isolated from gelatin back in 1820. Glycine is one of the nonessential amino acids for mammals; meaning that they can create it internally from two other amino acids: serine and threonine.
Glycine is found principally in gelatin and silk fibroin. It’s been used therapeutically as a nutrient, and also functions as a rapid inhibitory neurotransmitter in the central nervous system (CNS). Although glycine is both a simple and nonessential amino acid; experimental animals on low-glycine diets show reduced growth. The average adult will ingest 3 to 5 grams of glycine daily from dietary sources. Glycine is an amino acid that’s involved in the production of DNA, phospholipids, and collagen. It’s also involved in the release of energy.