Converts Fat Into Energy. Contains No Artificial Preservatives Color or Sweeteners. No Corn Dairy Gluten Soy Starch Wheat or Yeast. Suitable For Vegetarians. NAC (N-Acetyl-L-Cysteine) is a highly stable form of cysteine that provides antioxidant support and is especially beneficial for active people the elderly and those exposed to polluted environments. Natural Factors amino acids are the highest quality pharmaceutical grade products available.