Approximately five hundred amino acids occur in nature. Twenty of these are amino acids that serve as building blocks for proteins in the human body, these are referred to as 'fundamental amino acids'. These fundamental amino acids can be further subdivided into the categories 'essential', 'semi-essential' and 'non-essential'. Cysteine ​​is a semi-essential amino acid that the body can make itself from the amino acid L-methionine, but the synthesis of which is insufficient under certain circumstances to meet the need. Cysteine, like methionine, is one of the two fundamental amino acids that contain sulphur. N-acetyl-L-cysteine ​​(also called NAC) is the acetylated form of cysteine.

Supplementation with N-acetyl-L-cysteine ​​(NAC) has the advantage over L-cysteine ​​that it is better tolerated, has a higher bioavailability and is less sensitive to oxidation. After ingestion, NAC can be converted into cysteine, which is part of certain body proteins. Cysteine ​​is also one of the precursors of glutathione, which is formed via biosynthesis from the amino acids cysteine, glycine and glutamic acid.

Permitted health claims:
No.

N-acetyl-L-cysteine, anti-caking agent (rice fibre), vegetable capsule (pullulan, from fermented cassava starch).