is nac a precursor to glutathione biosynthetic scheme. N-acetyl-L-cysteine (NAC) can supply NAC and intracellular B12 processing:

L., & Razumovskaya, A

Concurrent impairment of Nrf2 signaling reduces antioxidant capacity, establishing a feed-forward loop characterized by progressive ROS accumulation, mitochondrial dysfunction, and muscle fiber degeneration

This paper is based on a presentation given at the Annual Meeting of the Society for the Study of Ingestive Behavior in July 2021 and provides a personal view on some of the milestones in the discovery of amylin as a constituent of pancreatic islet amyloid deposits, as a pancreatic beta-cell hormone, and on its role in physiology and pathophysiology

2016 May-Jun;82(3):262-72

CL Answer If I buy NAC as a loose powder in a large bag, as opposed to in tablet or capsule form, will it spoil

While glutathione is naturally produced by your body and oral supplements are broadly safe, certain groups should either avoid supplementation entirely or use it only under medical supervision: 1