Glycine is a non-essential amino acid for humans, which is mainly synthesised in the liver and kidneys. It functions as a precursor molecule for many metabolites such as haem, porphyrins, glutathione, collagen and many more. Glycine plays a vital role in the human metabolism and also acts a neurotransmitter (Razak et al., 2017).

Glycine can be used to chelate iron. The iron molecule is bound covalently to glycine via glycine's carboxyl and neutral α-amino group (EFSA NDA, 2006​​​​​​​).