NAC by Seeking Health provides 500 mg of N-acetyl-L-cysteine (NAC) per vegetarian capsule. NAC supports the health of the liver, brain, lungs, and other body tissues. Many of the beneficial actions of NAC are related to its role in supporting normal production of glutathione, one of the body's most important antioxidants. NAC is a well-absorbed supplemental form of cysteine, an amino acid required for the enzyme reaction that produces glutathione in the body. Typically the body's ability to produce glutathione will begin to decline with age. Daily exposures to environmental toxins may increase the need for antioxidant protection from glutathione. Providing the building blocks for glutathione, such as NAC, may help support healthy levels of glutathione and the body's healthy responses to these exposures.