Purity >90%. N,N'-Diacetyl-L-cystine (DiNAC) is a disulfide dimer of N-acetylcysteine with immunomodulatory properties. Its intact disulfide bridge has been shown to be important for its ability to modify contact sensitivity/delayed hypersensitivity reactions in mice. At 3 μM/kg/day, DiNAC also demonstrates anti-atherosclerotic effects, improving endothelial function in Watanabe heritable hyperlipidemic rabbits.