NAC (N-Acetyl Cysteine) is a form of the amino acid l-cysteine and acts as a powerful free radical scavenger. It is a precursor to and supports tissue levels of glutathione (GSH), the principle defense within the body against reactive oxygen species (ROS) and the detoxification of drugs, metabolites and other compounds. NAC also helps aid in the chelation of heavy metals and has been shown to support healthy lung function through its mucolytic capability.