Epitalon, also spelled Epithalon, is a synthetic tetrapeptide with the sequence Ala-Glu-Asp-Gly. It was developed from research on pineal peptide preparations and has been investigated in cellular-aging, telomere, circadian, antioxidant, and gene-expression models. Some laboratory studies report changes in telomerase activity and telomere-related endpoints, while human literature is largely composed of older studies from a limited number of research groups. Claims about lifespan extension or reversal of human aging should therefore be avoided.