What Livagen Is
Livagen is a synthetic tetrapeptide, Lys-Glu-Asp-Ala (KEDA), classified within the bioregulator family as hepatic-associated.
Its literature is small but unusually direct. Where most of the family is argued through phenotype — a tumour count, a behavioural score — one of the Livagen papers goes straight at the proposed mechanism, and it does so in human cells.
Research use only. Supplied for laboratory research. Not for human or veterinary use. No marketing authorisation exists and no therapeutic claim is made.
What the Published Studies Report
Chromatin activation in human lymphocytes
The central paper reports effects of Livagen on chromatin activation in lymphocytes from old people (Khavinson et al., Bull Exp Biol Med 2002, PMID 12533768).
This matters more than its citation count suggests. The family's proposed mechanism is that short peptides act on DNA and chromatin to modulate transcription. Chromatin decondensation in primary human cells is a direct test of that proposition rather than an inference from a downstream outcome — and the donor age is part of the design, not incidental.
Digestive enzyme activity across ages
A study in Advances in Gerontology examined the effect of Livagen on activity of digestive enzymes in the gastrointestinal tract and non-digestive organs in rats of different ages (Timofeeva et al., 2005, PMID 16075683). The inclusion of non-digestive organs is notable for the same reason the Cortagen heart study is: the design does not assume tissue confinement.
Enkephalin-degrading enzymes
Work examining the effect of Livagen and Epitalon on enkephalin-degrading enzymes in human serum (Kost et al., Izv Akad Nauk Ser Biol 2003, PMID 12942748) is a combination design, so results cannot be assigned to either peptide alone.
Reading the Evidence
The chromatin work is the strongest item because it tests the mechanism directly in human primary cells. It is still a cell-level result.
The hepatic label is weakly supported. Nothing in the three papers is a liver-function study; the association comes from the family classification scheme. If hepatic function is the research question, that gap should be explicit in the design.
No amount is established for any species or context.
Structure and Handling
- Sequence. Lys-Glu-Asp-Ala (KEDA), tetrapeptide.
- Formula. C18H31N5O9, 461.47 g/mol.
- Form. Lyophilised powder, ≥98% purity, third-party certificate of analysis per batch.
- Storage. Sealed vial at −20 °C, protected from light; reconstituted solution at 2–8 °C.
- Reconstitution. Bacteriostatic water down the vial wall, never onto the powder cake. Do not shake. See the reconstitution calculator.
The catalog record for this compound previously carried a molecular formula inconsistent with the stated sequence. It has been corrected against the sequence and verified. If you sourced material against the earlier figure, check the certificate of analysis for the batch you hold.
Related Compounds
Ovagen shares the hepatic association but has no study naming it. Epithalon appears alongside Livagen in the enkephalin work. Full family on the bioregulator overview.
Research Studies Overview
The published record for Livagen (KEDA) is small by any measure. Three peer-reviewed studies have been identified in indexed literature; all originate from the Khavinson group at the St. Petersburg Institute of Bioregulation and Gerontology. No independent replication by a separate laboratory has been located as of the date of this writing. The table below summarises the complete identified dataset.
| Study / Year | Model | Endpoint | Key Finding | PMID |
|---|---|---|---|---|
| Khavinson et al., 2002 | Human lymphocytes, elderly donors (ex vivo) | Chromatin activation state | Livagen reported to activate condensed chromatin in lymphocytes from aged donors; effect not observed to same degree in cells from younger donors | [1] 12533768 |
| Timofeeva et al., 2005 | Rat, multiple age cohorts (in vivo) | Digestive enzyme activity; non-digestive organs included | Reported modulation of enzyme activity in gastrointestinal tract and non-digestive organs; age-dependent differences noted | [2] 16075683 |
| Kost et al., 2003 | Human serum (ex vivo); combination design with Epitalon | Enkephalin-degrading enzyme activity | Changes in enkephalin-degrading enzyme activity reported; Livagen and Epitalon administered together — no per-compound attribution possible | [3] 12942748 |
Several design features recur and deserve explicit note. First, all three studies were conducted within a single research programme. This is not inherently disqualifying — many foundational bioregulator observations came from this group — but independent replication is absent, and the evidential weight is therefore limited accordingly. Second, the rat study (Timofeeva 2005) included organs outside the hepatic designation traditionally assigned to Livagen; the authors offer no explanation for why a peptide labelled as hepatic-associated should affect enzyme systems in non-digestive tissue, and the paper does not resolve this. Third, the Kost 2003 combination design is interpretively closed: a two-compound treatment with a single readout cannot isolate compound-specific contributions. The finding is reported here for completeness; it does not constitute independent evidence for any Livagen-specific pharmacological effect on enkephalin metabolism.
Proposed Molecular Mechanism: Peptide–Chromatin Interaction in the Context of Cellular Aging
The mechanistic proposal underlying the chromatin finding is that short peptides of the KEDA class interact directly with DNA or chromatin-associated proteins to alter nucleosome accessibility, thereby restoring or sustaining transcriptional capacity in aged cells. This proposal has not been tested for Livagen specifically at the molecular level — no binding study, co-immunoprecipitation, or structural analysis of KEDA with nucleosome components has been published in indexed literature. What follows is a description of the mechanistic context in which the chromatin observation would need to be interpreted, not a statement that the mechanism has been demonstrated for this compound.
Age-associated heterochromatin relaxation is a documented phenomenon in human somatic cells. Global loss of H3K9me3 and H4K20me3 marks, progressive decondensation of constitutive heterochromatin, and dysregulation of lamin-associated domains have all been described in the aging-cell literature as contributors to altered gene expression in senescent tissue.[4] If the Khavinson 2002 finding reflects a real biological effect of KEDA on chromatin structure, the mechanistic question is whether the peptide acts on histone modification enzymes, on chromatin remodelling complexes, on lamin-associated scaffolding, or on DNA directly through minor-groove interaction — a mode that has been proposed for other short cationic peptides but not demonstrated for KEDA.
The tetrapeptide's charge distribution is relevant here. The sequence Lys-Glu-Asp-Ala carries a net charge of approximately −1 at physiological pH (one basic residue, two acidic, one neutral), which does not obviously favour electrostatic attraction to DNA's phosphate backbone. This does not rule out indirect effects mediated through interaction with chromatin-associated proteins, but it makes direct DNA-groove binding a less parsimonious starting hypothesis. The proposed mechanism remains at the inference stage: plausible given the observed chromatin effect, mechanistically undefined, and untested at the molecular level in any published study. Research programmes seeking to advance this question would need chromatin immunoprecipitation data, nucleosome accessibility assays (ATAC-seq or MNase-seq), and ideally structural data on peptide–nucleosome interaction before the mechanism could be considered reported rather than proposed.[4]
Comparison with Structurally Related Bioregulators
Livagen belongs to a family of synthetic tetrapeptides developed within the same research programme that produced Epitalon (Ala-Glu-Asp-Gly), Vilon (Lys-Glu), Thymalin (a thymus-derived polypeptide fraction), and a range of tissue-targeted compounds including Cortagen (Ala-Glu-Asp-Gly in cardiac context) and Epitalon. A side-by-side assessment of these compounds against Livagen is constrained by the same problem that affects each compound individually: the evidence base for all of them derives predominantly from a single research group, independent replication is sparse across the family, and head-to-head comparative studies do not exist in the indexed literature.
What can be said structurally is this. Livagen (Lys-Glu-Asp-Ala) and Epitalon (Ala-Glu-Asp-Gly) share a Glu-Asp dipeptide core and differ at both termini. The shared acidic core has led to speculation that both compounds may share a common interaction surface, which would be relevant to interpreting the Kost 2003 combination study — but this is mechanistic inference, not data. Vilon, a dipeptide (Lys-Glu), overlaps with Livagen's N-terminal residues; if any component of the chromatin effect is attributable to that sub-sequence, Vilon would be a logical comparator in a controlled experiment, but no such experiment has been reported.
| Compound | Sequence | Designated Tissue | Highest-Quality Human Evidence | Independent Replication |
|---|---|---|---|---|
| Livagen | Lys-Glu-Asp-Ala | Hepatic | Ex vivo chromatin assay, elderly donors[1] | Not located |
| Epitalon | Ala-Glu-Asp-Gly | Pineal / endocrine | Combination design, human serum enzyme assay[3] | Limited; some independent citations in telomerase context |
| Vilon | Lys-Glu | Immune / thymic | Lymphocyte functional assays (Khavinson programme) | Not independently confirmed in indexed literature as of this writing |
| Cortagen | Ala-Glu-Asp-Gly | Cardiac | Preclinical cardiac tissue models | Not located |
The tissue-designation taxonomy applied across this family — hepatic, pineal, cardiac — reflects the organ from which the original peptide fraction was derived or the organ system most studied, not a demonstrated pharmacokinetic confinement. No biodistribution study for Livagen has been published. The Timofeeva 2005 rat data, by reporting effects in non-digestive organs, implicitly challenges the hepatic-confinement assumption for this compound specifically, but the study was not designed to test biodistribution and cannot be read as one.[2]
