Epithalon (also spelled Epitalon or Epithalone) is a synthetic tetrapeptide — a chain of four amino acids — with the sequence Ala-Glu-Asp-Gly. It has a molecular weight of 390.34 g/mol and the formula C₁₄H₂₂N₄O₉ (CAS 307297-39-8). It was first synthesized in the 1990s, modeled on the amino acid composition of epithalamin, a peptide extract from the bovine pineal gland. Epithalon is among the smallest peptides studied in bioregulation research. Its sequence contains two acidic residues — glutamic acid and aspartic acid — giving the molecule a net negative charge at physiological pH. It appears as a white lyophilized powder, dissolves readily in water, and requires refrigerated storage. This product is strictly for research purposes only.