GlycNAC is thought to provide its benefits largely by increasing the production of GSH. GlyNAC is simply glycine and cysteine (in the form of n-acetylcysteine), which are two of the three substrates necessary for the synthesis of GSH (via two enzymes: glutamate cysteine ligase and glutathione synthase).[1]
As well as acting as substrates from which GSH can be formed, glycine and cysteine also play their own role in many biochemical reactions, and thus should be kept at proper levels. Glycine contributes methyl groups (-CH3) to many chemical reactions (such as those involved in regulating gene expression), is a key component of cartilage, and is a neurotransmitter. Cysteine similarly donates sulfhydryl groups (-SH) to chemical reactions, binds to metal ions, and supports protein structure via the formation of disulfide bonds.[2][3]