L-Cystine

L-Cysteine is classified as a “semi-essential” amino acid because it can be made in small amounts by the human body, but many people can still benefit from consuming more cysteine from their diets or supplements because of its numerous health benefits. The human body can usually manufacturer L-cysteine from the amino acids serine and methionine, but you need enough folate, vitamin B6 and vitamin B12 for that to be possible.