NOW Glycine is a Pharmaceutical Grade supplement that promotes restful sleep and supports the nervous system. Glycine is the smallest and simplest amino acid, making it versatile for use in a wide range of functions. Glycine is necessary for the production of glutathione, DNA, creatine, bile, hemoglobin, and most proteins.* Glycine also helps to promote glycogen storage, thereby making glucose readily available for energy production.* Glycine functions as a calming neurotransmitter in the brain, where it facilitates nerve impulses and is important for the maintenance of healthy sleep patterns.*.