N-Acetyl Epitalon Amidate: Structure and What Is Published

Cover illustration: AI-generated editorial artwork. Conceptual only; not an exact molecular structure, actual laboratory result or evidence of clinical effects.

N-acetyl Epitalon amidate is Epitalon (Ala-Glu-Asp-Gly) with both ends capped: an acetyl group on the N-terminus and an amide at the C-terminus, written Ac-AEDG-NH2. Its calculated mass is about 431.4 g/mol. As of 2026-11-03 no PubMed record studies this capped form directly.

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Epitalon is the synthetic tetrapeptide Ala-Glu-Asp-Gly (AEDG), designed from the amino acid composition of the bovine pineal extract Epithalamin (Araj et al., 2025).
N-acetyl Epitalon amidate has the calculated formula C16H25N5O9 and a mass of about 431.4 g/mol, roughly 41 Da more than uncapped Epitalon (390.35 g/mol).
As of 2026-11-03, PubMed searches for “N-acetyl epitalon”, “epitalon amidate” and “Ac-AEDG-NH2” returned no records.
A 2026 narrative review searched PubMed and Google Scholar through 22 September 2026 and concluded that Epitalon is biologically active but clinically unproven (Jain et al., 2026).
Structure-activity data for 45 amidated peptide hormones showed the C-terminal amide was required for full activity of most of them (Merkler, 1994).

Summary card of the comparison table from the n acetyl epitalon amidate research article — Summary of the table in this article; the cited sources are listed under References.

Quick facts: the parent and the capped form

Property	Epitalon	N-acetyl amidate
Written as	H-AEDG-OH	Ac-AEDG-NH2
Formula	C14H22N4O9	C16H25N5O9 (calc.)
Mass, g/mol	390.35	~431.4 (calc.)
Free N-terminal amine	Yes	No (acetylated)
Free C-terminal acid	Yes	No (amide)
Ionisable side chains	Glu, Asp	Glu, Asp
PubMed records (2026-11-03)	Dozens	None found

The capped values are calculated, not measured. They follow from adding an acetyl group (C2H2O, +42.04) and replacing the terminal hydroxyl with an amino group (−0.98). Salt form and residual water change the weight of powder in a vial, so the certificate for a specific lot, not this table, is what a calculation of solution strength should start from. Our Epithalon research peptide listing describes the uncapped tetrapeptide.

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What each cap changes chemically

Epitalon at neutral pH is a highly charged small molecule. It carries a positive N-terminal amine, a negative C-terminal carboxylate, and two more negative side chains from glutamate and aspartate. Capping both ends removes two of those four charges. The net charge stays near −2 in both forms, but the capped molecule has lost the paired opposite charges at its ends, which changes how it interacts with water, surfaces and chromatography media. That sounds like a small edit. For a four-residue peptide, where the termini make up a large share of the surface, it is not.

Modification	Chemical effect	Practical consequence
N-acetylation	Amine becomes neutral amide	Loses one positive charge
C-amidation	Carboxylate becomes amide	Loses one negative charge
Both together	Termini uncharged	Less zwitterionic, more retained on C18
Both together	Ends no longer free	Exopeptidase recognition altered

N-terminal acetylation

In cells, alpha-N-acetylation is one of the most common protein modifications. Acetyltransferase complexes add the acetyl group from acetyl-coenzyme A to nascent N-termini, and the modification has been linked to folding, stability, activity and localisation (Van Damme et al., 2011). That literature concerns proteins, not synthetic tetrapeptides. Its relevance here is narrower: it shows that the N-terminal acetyl group is a recognised biological signal, so adding one to a peptide is a structural change rather than a protective coating.

C-terminal amidation

Many natural peptide hormones end in an amide, made by the peptidylglycine alpha-amidating enzyme from a glycine-extended precursor. Merkler compiled structure-activity data on 45 such hormones and found that removing the amide reduced or abolished full activity for most of them (Merkler, 1994). Epitalon itself ends in glycine and is not naturally amidated, so the reverse question applies: adding an amide to a peptide that did not have one may change activity in either direction, and only testing can say which.

What the Epitalon literature actually covers

Everything published under the Epitalon name concerns the uncapped sequence. The main lines of work are summarised below, with the model named in each case.

Study	Model	Reported finding
Khavinson et al., 2003	Fetal fibroblast culture	Telomerase subunit expression, activity
Khavinson et al., 2020	Gingival stem cells	Neurogenic markers up 1.6–1.8 fold
Araj et al., 2025	Review	Few physico-chemical studies
Jain et al., 2026	Narrative review	Active, clinically unproven

The 2003 study added Epitalon to telomerase-negative human fetal fibroblasts and reported expression of the catalytic subunit, telomerase activity and telomere elongation (Khavinson et al., 2003). The 2020 study measured neurogenic differentiation markers in human gingival mesenchymal stem cells and used molecular modelling to propose binding to histone H1 sites (Khavinson et al., 2020). Both groups attribute these effects to the native tetrapeptide; neither tested capped analogues.

The 2025 overview is the most useful for a structural question. Its authors note that despite a large volume of biological work, physico-chemical and structural investigations of Epitalon remain limited (Araj et al., 2025). If the parent is under-characterised, the capped derivative is more so.

The 2026 review is the most critical. It separates synthetic Epitalon from the older Epithalamin extract, appraises studies by design and replication, and finds that human evidence is limited to small biomarker studies and one older controlled study, with pharmacokinetic and long-term safety data inadequate and regulatory questions unresolved after a 2026 FDA advisory review (Jain et al., 2026).

Why the capped form appears on the market

The logic offered for capping short peptides is protection from exopeptidases, the enzymes that trim amino acids from free ends. That reasoning is general and plausible, but for this specific molecule no stability or activity comparison was found. The same pattern is seen with other capped research peptides such as N-acetyl Semax amidate and N-acetyl Selank amidate, where the capped name circulates more widely than any data comparing it with the parent.

For a laboratory, the practical implication is that the capped and uncapped forms are two different test articles. A result obtained with one should be reported with its exact structure, and not cited as evidence for the other.

Handling in the lab

Uncapped Epitalon is acidic and dissolves readily in water. The capped form keeps both acidic side chains, so it is also expected to be water-soluble, though it carries less charge and may behave differently at high concentration. Neither form contains methionine, cysteine or tryptophan, so oxidation is not the main concern; hydrolysis and aspartate-related rearrangement in solution are the more likely slow changes, and cold, single-use aliquots limit both.

Concentration arithmetic is the same for either form: net peptide mass divided by diluent volume, which the peptide calculator handles. The two molecules are distinguished by mass spectrometry, with the capped form near 431 and the parent near 390. Background on the parent, including the Epithalamin history, is in the Epithalon overview, and the related thymus extract is compared in Epithalon versus Thymalin.

Telling the four possible forms apart by mass

A capped tetrapeptide can be incompletely capped. Synthesis can leave a fraction acetylated but not amidated, or the reverse, and an amide can slowly hydrolyse back to the acid in solution. The calculated monoisotopic masses below show which of these a mass spectrum can separate.

Form	Formula (calc.)	Monoisotopic	[M+H]+
H-AEDG-OH (Epitalon)	C14H22N4O9	390.139	391.146
H-AEDG-NH2	C14H23N5O8	389.155	390.162
Ac-AEDG-OH	C16H24N4O10	432.149	433.156
Ac-AEDG-NH2	C16H25N5O9	431.165	432.172

The acetyl group is easy to see: it moves the mass by 42 Da. The amide is harder, because amide and acid differ by only 0.98 Da. On a low-resolution instrument the fully capped peptide and its hydrolysed, acetyl-only product sit one mass unit apart and can overlap with isotope peaks. A high-resolution measurement, or a chromatographic method that separates the two by charge, is needed to confirm the C-terminus. That distinction matters more for this derivative than for most peptides, since the amide is the feature that defines it.

Short bioregulator peptides from the same research school are surveyed in Russian bioregulator peptides. General guidance on reading the identity section of a certificate is in how to read a peptide COA.

Frequently asked questions

What is N-acetyl Epitalon amidate?

It is the tetrapeptide Epitalon (Ala-Glu-Asp-Gly) with an acetyl group on the N-terminal amine and an amide in place of the C-terminal carboxylic acid, written Ac-AEDG-NH2. The amino acid sequence is unchanged; only the two ends are capped.

What is the molecular weight of N-acetyl Epitalon amidate?

Calculated from the parent formula C14H22N4O9 (390.35 g/mol), acetylation adds C2H2O and amidation exchanges an OH for an NH2, giving C16H25N5O9 and about 431.4 g/mol. These are calculated values; the certificate for a given lot is the reference for the material in hand.

Is there published research on N-acetyl Epitalon amidate specifically?

As of 2026-11-03, PubMed searches for “N-acetyl epitalon”, “epitalon amidate” and “Ac-AEDG-NH2” returned no records. The published Epitalon literature concerns the uncapped tetrapeptide, and not finding a record does not prove that no study exists elsewhere.

Do Epitalon findings apply to the capped version?

Not automatically. Capping removes the two terminal charges and can change how a peptide is recognised by enzymes and binding partners. Merkler’s survey of 45 amidated peptide hormones found the C-terminal amide was required for full activity of most of them, which shows how much an end cap can matter (Merkler, 1994).

How can the two forms be told apart in the lab?

By mass. The capped form is about 41 Da heavier than Epitalon, a difference any routine mass spectrometry run resolves. Retention time on reversed-phase HPLC is also expected to shift, because the capped molecule carries less charge.