Glutathione is made up of three amino acids, which include glutamine, cysteine and glycine. Naturally exogenous glutathione is supplied to the body in the form of fruit and vegetables. Concentrations of the compound vary depending on the type of plants and properties. Glutathione of plant origin is poorly absorbed, which may be due to the digestive enzymes present in the stomach.

Glutathione has two forms: oxidised (GSSG) and reduced (GSH). Only the reduced form is responsible for the interesting properties of the tripeptide. And this reduced form is provided by Zein Pharma - L-Glutathione. A supplement in capsule form containing reduced l-glutathione. Two capsules (recommended daily serving) contain 500 mg. The product is also aimed at vegans and vegetarians.