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 can donate or accept one-carbon units via the folate cycle (which indirectly supports or influences gene expression).[2] Cysteine similarly donates sulfhydryl groups (-SH) to chemical reactions, binds to metal ions, and supports protein structure via the formation of disulfide bonds.[3][4]