N-acetyl cysteine (NAC) comes from the amino acid L-cysteine. Amino acids are building blocks of proteins. NAC is used by the body to build antioxidants. Antioxidants could protect and repair cells from damage. It also has been shown to increase Glutathione reserves in the body.
Additionally, N-acetyl-L-cysteine is a chemical precursor to glutathione, one of the body’s most important antioxidants. Glutathione is important due to how it could protect cells against free radicals. Which could also boost the immune system.