NAC, the acetyl derivative of L-cysteine, is more stable than L-cysteine, & can convert into L-cysteine after being absorbed. NAC is a natural source of sulfur for metabolism, & an antioxidant that supports glutathione synthesis. NAC may be used instead of L-cysteine as an adjunct to Item 50130 Original Anti Ox. Free form amino acid, high purity, well tolerated, & in tablet form to insure potency.