Powerful Free Radical Scavenger. Hypo-Allergenic Dietary Supplement. N-Acetyl-l-Cysteine (NAC) is a derivative of the dietary amino acid l-cysteine. NAC has a high affinity for lung tissue, which it supports through mucolytic and antioxidant action. By disrupting disulfide bonds, NAC thins mucus. It is a powerful free radical scavenger and thus supports the body's natural defense system. NAC supports tissue levels of glutathione, a key component of the antioxidant defense system. It also has the ability to help chelate heavy metals. NAC provides powerful nutritional support to cells as an antioxidant and specifically supports healthy lung functioning through its mucolytic capability.