Epitalon / what it is
What Is Epitalon? The AEDG Tetrapeptide, Explained
The four-residue chemistry of the Epitalon peptide, where it came from, and the precise distinction between Epitalon and epithalamin.
The gist
The Epitalon peptide is one of the smallest molecules in the longevity-research world: just four amino acids strung together, written Ala-Glu-Asp-Gly, or AEDG. "Tetra" means four, so it is a tetrapeptide. It was not invented from scratch — it is the short active sequence pulled out of a much messier substance called epithalamin, an extract of the pineal gland (a tiny hormone-making gland in the brain). Researchers wanted a clean, defined molecule to study instead of a crude extract, so they synthesized the four-amino-acid core. That is the whole idea: take the part of the pineal extract thought to do the work, make it precisely, and study it. The two are related but not the same thing — a distinction that gets blurred constantly in marketing, and one this page draws carefully.
The chemistry of the Epitalon peptide
Epitalon (also spelled Epithalon) is the linear tetrapeptide H-Ala-Glu-Asp-Gly-OH. Its molecular weight is 390.35 Da, its formula is C14H22N4O9, and its CAS number is 307297-39-8 (PubChem CID 219042, FDA UNII O65P17785G). The single-letter amino-acid code AEDG spells the sequence: Alanine-Glutamate-Aspartate-Glycine. As a short, unmodified peptide it carries no stabilizing modifications, which is why it is expected to break down quickly in plasma [4]. The molecule is fixed and simple — four residues, one sequence — which is part of why the 2025 review notes that despite this simplicity, its full physico-chemical and structural characterization is still limited [4].
Where Epitalon came from
Epitalon is a synthetic analog modeled on epithalamin, a peptide complex isolated from the pineal gland (epiphysis). It is not itself a documented endogenous human peptide; rather, it represents the proposed active sequence of the parent complex, whose activity is reported to decline with age. The synthesis and the bulk of the early study came from Vladimir Khavinson and colleagues at the St. Petersburg Institute of Bioregulation and Gerontology, beginning in the 1970s-1980s [1] — the single research lineage whose provenance qualifies most of the Epitalon record.
Epithalamin
Epithalamin is the parent material: a polypeptide extract of the bovine pineal gland, not a single defined molecule. It is the preparation from which the synthetic Epitalon tetrapeptide was derived. This is the most important distinction on the site: epithalamin is a complex biological extract, while Epitalon is a single, defined synthetic four-amino-acid peptide. Their evidence bases are separate. The most-cited human longevity data — the 6-8 year, 266-subject cohort showing reduced mortality — tested Epithalamin, the extract, not synthetic Epitalon [2]. Treating the two as interchangeable, as some material does, overstates what is known about the synthetic peptide.
Epithalamin peptide
Calling epithalamin a "peptide" is a slight simplification: the epithalamin peptide preparation is a complex of pineal polypeptides rather than one peptide, which is exactly why a defined synthetic stand-in was developed. When a study or product refers to the epithalamin peptide, it is pointing at the bovine-pineal extract and its observational human record [2], not at the AEDG tetrapeptide. Keeping the epithalamin peptide and the Epitalon tetrapeptide in separate columns is the single best guard against the conflation that inflates Epitalon's apparent evidence base.
Epithalamin supplement
An epithalamin supplement is not an approved medicine and not a characterized pharmaceutical: neither epithalamin nor Epitalon holds FDA, EMA, or MHRA approval, and Epitalon specifically is classified as a research chemical, not a dietary supplement [4]. Material marketed as an epithalamin supplement should be read with the sourcing caution that the research-use community itself raises — research-grade material is unregulated, so contents and purity of any given vial are uncertain. This site does not sell, source, or recommend any such product; it documents the literature only.
Epithalamine
Epithalamine is simply an alternative spelling of epithalamin, the bovine-pineal peptide preparation; the two terms refer to the same parent extract. A study titled for the geroprotective effect of "epithalamine" in elderly subjects with accelerated aging, for instance, is reporting on the same class of pineal-extract material as epithalamin [15]. The spelling varies across the older Russian literature and its translations; the substance does not. As with epithalamin, epithalamine refers to the extract, not to the synthetic Epitalon tetrapeptide.