WHAT IS N-ACETYL L-CYSTEINE (NAC)? N-Acetyl L-Cysteine, more commonly known as NAC, is a pre-cursor to Glutathione. L-Cysteine can be found naturally in the body as well as in foods such as chicken, red peppers & egg yolks. However, supplementing with L-Cysteine is extremely unstable, whereas N-Acetyl L-Cysteine provides a stable form. The specific form NAC can’t be obtained via the diet. BULK POWDERS™ N-Acetyl L-Cysteine is of the highest quality – a quick glance at the