Free Radical Protection With Selenium & Molybdenum Maintains Cellular Health Non-GMO A Dietary Supplement Kosher Amino Acids Family Owned Since 1968 GMP Quality AssuredN-Acetyl Cysteine (NAC) is a stable form of the non-essential amino acid L-Cysteine. It is a sulfur-containing amino acid that acts as a stabilizer for the formation of protein structures, and is also necessary for the formation of glutathione. Molybdenum and selenium are essential trace minerals that facilitate the production of several important enzymes.