Epitalon

At a Glance

Epitalon (Ala-Glu-Asp-Gly, abbreviated AEDG) is a synthetic tetrapeptide developed based on the amino acid composition of epithalamin, a bovine pineal gland extract. Over the past 25 years, it has been extensively studied in preclinical models for potential geroprotective and neuroendocrine effects.

The peptide is primarily studied through subcutaneous injection at doses of 1 µg/mouse (in mice studies) or 5 µg/rat (in rat studies), typically administered 5 times per week. Some studies also report oral and intranasal administration. [PMID: 40141333]

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Molecular Structure

Epitalon is a tetrapeptide composed of four amino acids in the following sequence:

• Alanine (Ala)
• Glutamic Acid (Glu)
• Aspartic Acid (Asp)
• Glycine (Gly)

Abbreviated as AEDG. It was synthesized based on epithalamin, a complex bovine pineal gland extract. [PMID: 40141333]

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Mechanism of Action

Epitalon exhibits multiple biological effects through various mechanisms:

Well-Documented Effects:

• Telomerase activation: Increases telomerase activity in cell culture models [PMID: 12937682]
• Melatonin synthesis: Direct influence on melatonin synthesis and regulation
• Interleukin-2 modulation: Alters mRNA levels of IL-2 in hypothalamic structures
• Thymocyte activity: Modulates mitogenic activity of murine thymocytes
• Enzyme modulation: Enhances activity of acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), and telomerase

Reported Biological Effects:

• Antioxidant: Reduces reactive oxygen species and lipid peroxidation
• Neuro-protective: Protects neurons from age-related changes
• Antimutagenic: Reduces chromosome aberrations and genotoxic effects
• Anti-tumor: Inhibits growth of certain spontaneous and induced tumors in animal models

The review notes that while these mechanisms have been observed, it remains uncertain whether they represent the complete or sole mechanisms of action. Effects have been reported at both standard doses and ultra-low concentrations (10^-17 to 10^-15 M), suggesting complex dose-response relationships. [PMID: 40141333]

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Evidence Summary

Comprehensive Review (2025)

~ Moderate Confidence Review

A comprehensive 2025 review in International Journal of Molecular Sciences analyzed 25 years of epitalon research across in vitro, in vivo, and in silico studies. The review reports significant geroprotective and neuroendocrine effects with antioxidant, neuro-protective, and antimutagenic properties. [PMID: 40141333]

Telomerase/Telomeres (Cell Models)

◆ Low Confidence In Vitro >10 Years

Human somatic cell experiments (2003) reported induction of telomerase activity and increased telomere length using the Telomeric Repeat Amplification Protocol (TRAP). Studies used telomerase-positive HeLa cultures and human fetal lung fibroblasts. [PMID: 12937682]

Lifespan Extension (Animal Models)

◆ Low Confidence Animal Study 3-10 Years

Studies in Drosophila melanogaster (fruit flies) and mice have reported lifespan extension effects. In flies, epitalon extended lifespan and the effective dose was substantially lower than comparator melatonin (requiring ~16,000-fold higher concentrations for comparable effects). [PMID: 40141333]

Anti-Tumor Effects (Animal Models)

◆ Low Confidence Animal Study 3-10 Years

Multiple mouse studies report inhibitory effects on spontaneous and induced tumors:

• HER-2/neu transgenic mice: Reduced breast tumor incidence
• Colon carcinogenesis models: Inhibited tumor development
• Various spontaneous tumor models: Reduced tumor incidence [PMID: 40141333]

Retinal Protection (Animal/Clinical)

◆ Low Confidence 3-10 Years

Studies report retinoprotective effects in rat models of retinitis pigmentosa and limited human clinical studies with parabulbar injections (5 µg per eye, 10 consecutive days). [PMID: 40141333]

Neuroendocrine Regulation (Animal Models)

◆ Low Confidence Animal Study 3-10 Years

Studies in rats demonstrate epitalon restores pinealectomy-induced changes in gastric endocrine cells, spleen morphology, and various hypothalamic neuroendocrine functions, including IL-2 mRNA synthesis regulation. [PMID: 40141333]

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Administration & Pharmacokinetics

Reported Administration Routes:

• Subcutaneous injection (most commonly studied)
• Intraperitoneal injection
• Intranasal administration
• Oral (some reports suggest low-hydrolyzable properties)
• Intramuscular injection
• Parabulbar injection (ophthalmic studies)

Typical Doses (Animal Studies):

• Mice: 1 µg/mouse, 5 times/week (long-term studies)
• Rats: 5 µg/rat for 30-42 days (various endpoints)
• Ultra-low doses: 10^-17 to 10^-15 M (reported in vitro activity)

Pharmacokinetics: The review notes that short peptides such as epitalon are typically unstable and degrade rapidly in vivo. Chemical modification or formulation strategies may be needed to improve stability and extend half-life. Specific plasma half-life data is not reported; the current estimate (~30 min) is based on structural similarity to other tetrapeptides. [PMID: 40141333]

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Safety & Unknowns

Reported Safety Observations:

• No reported genotoxic effects in Drosophila studies at effective doses
• No chromosome aberrations in long-term murine studies
• Generally well-tolerated in animal studies at researched doses

Major Limitations:

• Human clinical safety and efficacy are not established by existing studies
• Nomenclature confusion exists between epitalon, epithalon, epithalone, and related epithalamin
• The review explicitly states that safety data is missing for critical issues including:
  • Short- and long-term toxicity
  • Genotoxic activity
  • Carcinogenic potential
  • Food-drug and drug-drug interactions
• Mechanisms of action remain partially unverified
• Effects may involve both specific (receptor-mediated) and nonspecific mechanisms

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Regulatory Status

Region	Status
United States (FDA)	Not approved
European Union (EMA)	Not approved
Russia	Epithalamin (related extract) studied clinically; epitalon status unclear

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Key Historical Context

Epitalon was synthesized based on epithalamin, a peptide complex from bovine pineal glands first described by V.K. Khavinson and V.N. Anisimov. Epithalamin has been more extensively studied, including clinical trials, and is referenced as a “geroprotective agent.” Epitalon represents the simplified synthetic tetrapeptide version. [PMID: 40141333]

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Changelog

Date	Change
2026-01-31	Major update: Added 2025 IJMS review (PMID 40141333) with expanded mechanism details, administration data, and evidence summary
2026-01-23	Initial dossier with PMID 12937682 study