Epithalon (also Epitalon or Epithalone) is a synthetic tetrapeptide, Ala-Glu-Asp-Gly (AEDG), designed on the basis of the amino acid composition of epithalamin, a polypeptide extract of bovine pineal gland. Much of the early literature comes from the group of Khavinson and Anisimov. Studies have examined telomerase expression and telomere length in human cell cultures, proliferative lifespan of fetal fibroblasts, and lifespan and tumour incidence in mice. A 2025 review noted that, despite the volume of biological work, physicochemical and structural studies of the peptide remain limited.