N-acetyl cysteine (NAC) is a stable form of the non-essential amino acid cysteine. It is a sulfur-containing amino acid that acts as a stabilizer for the formation of protein structures and promotes the formation of glutathione.* Glutathione is a powerful free radical scavenging compound that also helps to maintain normal balanced immune system function.* In addition NAC can help to support healthy brain and neuronal tissues.* Natural color variation may occur in this product. As a family-owned company since 1968 — NOW produces high-quality natural products at prices everyone loves. We are a respected leader in the natural products industry with a mission to provide value in products and services that empower people to lead healthier lives.