NAC N-Acetyl-Cysteine supplements are popular with people want to promote overall cellular health. N-Acetyl-Cysteine or NAC, comes from the amino acid cysteine which is building block of protein found in food. It is used by the body to build antioxidants and other nutrients that protect and repair cells from damage. NAC is also a building block for another nutrient called glutathione which may be a potent detoxifying nutrient. This is why NAC is best known as a nutrient that may detoxify the liver and boost the immune system. N-Acetyl-Cysteine cannot be obtained directly from food sources, which is why NAC supplements are popular. Mason Natural NAC contains a high-potency 500 mg of N-Acetyl-Cysteine per capsule.