Glycine is a conditionally essential amino acid, meaning your body produces this amino acid naturally, but not always in the amount necessary for optimal health.* It plays important roles in several bioactivities in the body, including the production of proteins, collagen, glutathione, and DNA.* Glycine also functions as a neurotransmitter in the brain, where it can send both stimulatory and depressant messages.* Due to these roles, glycine may promote a mellow and relaxed mood, support restful sleep, and digestive health.*