Testagen

Testagen is the synthetic tetrapeptide Lys-Glu-Asp-Gly, usually written KEDG. It is one of the short "peptide bioregulators" developed by V. Kh. Khavinson and colleagues at the Saint Petersburg Institute of Bioregulation and Gerontology, whose review tables list the testagen peptide as a regulator of male reproductive system function (Khavinson et al., 2021; Khavinson et al., 2022), although no indexed study has examined it in reproductive tissue.

A Chita group that tested the same sequence describes it as designed from anterior pituitary extracts (Kuznik et al., 2011). The record is small, comes almost entirely from one research network and includes no human study.

Formula and weight come from PubChem CID 123863700, so the two sources do not conflict. MeSH, the National Library of Medicine's index, files the sequence as lysyl-glutamyl-aspartyl-glycine.

Published work on Testagen falls into five areas, summarized below with their models. PubMed indexes two papers under the name and about eight more under the sequence. Nearly all of the biology comes from Khavinson's institute or groups that publish with him, a Moscow laboratory and a Chita group led by his long-time co-author B. I. Kuznik, often in Russian journals or their English translations. All of it is bird, cell, cell-free or computer-model work.

The name and the tissue label

The name suggests the testes, and the group's 2021 systematic review lists KEDG under "regulation of male reproductive system function" (Khavinson et al., 2021). The three papers cited for that row are a histone-binding study, a review of cell differentiation and a mouse heart study of two other peptides. We found no indexed study of testagen in testicular tissue or cells.

The differentiation review lists KEDG among peptides it says stimulate immune cell differentiation (Khavinson et al., 2020). The Chita papers describe Lys-Glu-Asp-Gly as designed from anterior pituitary extracts, paired with Ala-Glu-Asp-Gly, the epitalon sequence, which they place in the posterior lobe (Kuznik et al., 2011). The St Petersburg group instead describes epitalon as designed from a pineal extract (see the epitalon research guide). Model: none (review and design statements).

Hypophysectomized birds

Five papers from Kuznik's group test KEDG side by side with Ala-Glu-Asp-Gly in chickens whose pituitary was removed. In neonatally hypophysectomized chickens, 40 days of the tetrapeptides was followed by higher thyrotropin and thyroid hormone levels and recovery of thyroid structure (Kuznik et al., 2008). A Russian-language report added that both peptides prevented thyroid atrophy and normalized immune and hemostatic parameters disturbed by the operation (Kuznik et al., 2010).

The response was weaker in older birds: in old hens than in chickens operated at 5 days (Kuznik et al., 2011), and in five-year-old than in one-year-old birds (Kuznik et al., 2011). In the thymus, both peptides promoted recovery of structure at every age, KEDG more than Ala-Glu-Asp-Gly (Pateyk et al., 2013). Thyrotropin is normally made by the anterior pituitary, and the abstracts do not say how complete removal was confirmed. Model: chickens and hens.

Nuclear entry, DNA and histone binding

In HeLa cells, a human cervical cancer line, fluorescein-labeled testagen, epitalon and pinealon appeared in the cytoplasm, nucleus and nucleolus. In cell-free tests, the unlabeled peptides quenched labeled DNA fragments to different degrees, and testagen, like epitalon and pinealon, appeared to prefer CAG-containing sequences (Fedoreyeva et al., 2011). KEDG was also one of six short peptides that bound fluorescein-labeled wheat histones H1, H2B, H3 and H4, with binding that varied with the histone, peptide and oligonucleotide (Fedoreyeva et al., 2013). Models: HeLa cells, synthetic DNA and purified plant histones.

Transporter docking

The developers' 2022 review gives KEDG a docking score at LAT1, an amino acid transporter (Khavinson et al., 2022). In a 2023 study of 26 short peptides, it ranked sixth at LAT1, ninth at LAT2 and seventh at PEPT1 but 23rd at PEPT2, and the authors grouped it with the most effective transporter ligands (Khavinson et al., 2023). We found no indexed measurement of KEDG transport. Model: molecular docking.

Copper corrosion

The one indexed paper from outside this network is materials chemistry: Romanian chemists reported that testagen inhibited copper corrosion in 0.9% sodium chloride by about 86% at 20 mg/L, with a free energy of adsorption of -30.86 kJ/mol that they read as mixed physical and chemical adsorption (Dobriţescu et al., 2025). It addresses no biological question. Model: copper electrodes plus computer simulation.