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 and 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.