the stable form of l-cysteine ,free form for enhanced absorption ,the grade used in clinical nutrition products ,suitable for vegetarians and vegans n-acetyl-cysteine nac), is a stable form of the amino acid cysteine, but unlike cysteine (which naturally occurs in foods such as eggs, chicken, red peppers), nac cannot be obtained from dietary sources. instead, it\'s converted in the body into the powerful antioxidant glutathione. nac is one of the few amino acids to contain sulphur, with its associated sulphur smell. although this smell is quite normal, we\'ve chosen a capsule form over a straight powder, to reduce the incidence of any odour. each small, easy to swallow capsule contains a full 600mg of pure nac, a useful level that\'s consistent with studies. like all of nature\'s best® supplements, great care is taken to produce a nac supplement of the highest quality, delivering unbeatable value.n-acetyl cysteine makes the perfect partner to many supplements in our range including vitamin c, bromelain, oracomega® and orac 10,000.