spec sheet11 rows
Testagen is a synthetic tetrapeptide, Lys-Glu-Asp-Gly, from the Khavinson family of short peptide bioregulators [1]. The experimental literature describes it as an ANTERIOR PITUITARY peptide and tests it on the thyroid, the thymus, immunity and clotting in hypophysectomised birds [2][3][5][6]; the male reproductive description that usually accompanies it comes from review tables rather than from an experiment [9][10]. All of the evidence is animal or cell culture. There is no human data.
- Synthetic tetrapeptide Lys-Glu-Asp-Gly from the Khavinson family
- Raised thyroid hormones and restored thyroid structure in birds
- Promoted thymic recovery in the same bird model
- Normalised immune and clotting measures in birds
- Enters the nucleus and nucleolus of human cells
- Unknown in humans; nothing has been systematically looked for
- Raises TSH, T3 and T4 in animals, so it is not inert alongside thyroid disease or thyroid medication [2][3][4]
- One animal study reported changes in coagulation and fibrinolysis, never followed up [5]
- Every wet-lab paper on Testagen calls it an anterior pituitary peptide and measures thyroid hormones. Not one has ever measured testosterone.
- The only research group outside the Russian school to publish on this molecule used it to stop copper corroding in salt water, where it reached about 86 percent inhibition.
- There is a registered Phase 2 clinical trial called Testagen. It is a transdermal testosterone spray from an unrelated company that happens to share the trade name, and it has nothing to do with the peptide.
Mechanism
The proposed mechanism is the one the whole bioregulator family shares: the crosses the cell and nuclear membranes without a receptor, binds DNA and histone tails, and switches on the transcription programme of its home tissue [10][12]. Three things have actually been shown, all in vitro and all from one laboratory group. Fluorescein-labelled Testagen was seen in HeLa cytoplasm, nucleus and nucleolus [1]. Fluorescence quenching constants suggested a preference for CAG-containing sequences [1]. The same method showed binding to labelled WHEAT histones H1, H2B, H3 and H4 at their N-terminal regions [7].
⚠️ Fluorescence quenching is an indirect binding readout. There is no structure, no ChIP, no reporter assay, no measured dissociation constant against a human target, and no transcriptomic experiment on this at all. How it would reach a cell is unresolved; a docking study scored it favourably against LAT1, LAT2 and PEPT1 while measuring no transport, and modelled 26 peptides at once [8].
The only mechanism with repeated whole-animal support is endocrine and it is not the advertised one. In five studies from one Russian group, KEDG synthesised from the amino acid composition of anterior pituitary cytomedins raised thyrotropic and thyroid hormone levels and restored thyroid structure in hypophysectomised chickens [2], did so again in young chickens and old hens with the effect weaker in the old birds [3][4], normalised immune and haemostatic parameters in the same model [5], and promoted recovery of thymic morphology more strongly than its posterior-lobe counterpart [6]. No receptor was identified in any of them.
receptor fingerprint
Anterior pituitary, TSH secretionraised thyrotropic hormone in hypophysectomised birds across five studies from one group; no receptor identified and no mammalian data
Thyroid follicular epitheliumraised T3 and T4 and prevented atrophic change, downstream of the TSH effect
Cell nucleus and nucleolusfluorescent peptide observed inside HeLa nuclei; a property rather than a target
Thymuspromoted recovery of thymic morphology, more strongly than the posterior-lobe peptide
Double-stranded DNA, CAG-leaning sequencesfluorescence quenching only, one group, no measured dissociation constant
Histones H1, H2B, H3, H4binding at N-terminal motifs, measured by fluorescence quenching; the histones tested were from wheat
LAT1 / LAT2 / PEPT1 transportersfavourable docking scores only; no transport was assayed
Testis, Leydig cells, androgen axisno androgen endpoint has been measured in any species; the description traces to two review tables rather than to an experiment
Safetyrisks and cautions, not medical advice
HUMAN SAFETY DATA: none. No trial, no case report, no pharmacokinetics, no toxicology, and no registered study anywhere. That is absence of investigation, not evidence of safety.
Two specific cautions follow from the actual data rather than from generic hedging. First, the best-replicated effect of this peptide is RAISING TSH, T3 and T4 [2][3][4]. Whatever else that is, it is not inert in anyone with thyroid disease or taking thyroid medication, and it is the opposite of what a marketing claim about testosterone would lead a buyer to expect. Second, one study reported it normalising hypercoagulation and depressed fibrinolysis after hypophysectomy [5], which means the molecule was measurably doing something to clotting in that model. Neither has ever been followed up in a mammal.
All in-vivo work is in chickens and hens, in a hypophysectomy model with no human counterpart.
Reconstitutionarithmetic only, not dosing advice
arithmetic only; not medical or dosing advice.
History
Testagen belongs to the peptide bioregulator programme founded by Vladimir Khavinson at the St Petersburg Institute of Bioregulation and Gerontology. The method began with cytomedins, crude peptide extracts from animal organs, and moved to synthetic short peptides said to reproduce the amino acid composition of those extracts; the founding claim is that such a peptide stimulates growth in explants of the tissue its parent complex came from [14]. That doctrine is what gives every peptide in the family a marketed organ.
⚠️ Testagen's placement in that family is unusually unstable, and it is worth seeing how the layers disagree. The experimental papers call it an anterior pituitary peptide [2][6]. A 2020 review lists it under immune cell differentiation [11]. A 2022 review table calls it a regulator of the male reproductive system and gives no source, while the rows around it are sourced [9]. The only patent on the molecule, RU2325397 from 2008, covers Lys-Glu-Asp-Gly for stimulating thyrotropic and thyroid hormones. The organ on the label looks assigned by the name rather than by the data.
The one genuinely independent paper on this molecule comes from a Romanian chemistry group and is about using it to inhibit copper corrosion in saline, at about 86 percent efficiency [13]. It is listed here because it is the only paper outside the originating network that names the compound, and because it is a useful reminder of what a short charged peptide is: a small, sticky, generically reactive molecule.
Regulatory status: not approved anywhere in the West, with no registered clinical trial. Material sold under this name is an unregulated research chemical.
Where to buy
Suppliers
Vendors carrying Testagen, with live product details and codes. Links are affiliate links that support the wiki at no cost to you.
Kimera Chems
Testagen
Research
- 2001first citedTissue-specific effects of peptides.
- 2011most active year3 papers
- 2025most recentThe Inhibitory Effect and Adsorption Properties of Testagen Peptide on Copper Surfaces in Salin…
- 1.Penetration of short fluorescence-labeled peptides into the nucleus in HeLa cells and in vitro specific interaction of the peptides with deoxyribooligonucleotides and DNA.
- 2.Effect of tetrapeptides Lys-Glu-Asp-Gly and Ala-Glu-Asp-Gly on the structure and function of the thyroid gland in neonatally hypophysectomized chickens.
- 3.Effects of peptides Lys-Glu-Asp-Gly and Ala-Glu-Asp-Gly on hormonal activity and structure of the thyroid gland in hypophysectomized young chickens and old hens.
- 4.[Effects of Lys-Glu-Asp-Gly and Ala-Glu-Asp-Gly peptides on hormonal activity and thyroid morphology in hypophysectomized mature and old birds].
- 5.[Effects of hypophyseal Lys-Glu-Asp-Gly and Ala-Glu-Asp-Gly synthetic peptides on immunity, hemostasis, morphology and functions of the thyroid gland in neonatally hypophysectomized chicken and one-year-old birds].
- 6.Effect of peptides Lys-Glu-Asp-Gly and Ala-Glu-Asp-Gly on the morphology of the thymus in hypophysectomized young and old birds.
- 7.Interaction of short peptides with FITC-labeled wheat histones and their complexes with deoxyribooligonucleotides.
- 8.Feasibility of Transport of 26 Biologically Active Ultrashort Peptides via LAT and PEPT Family Transporters.
- 9.Transport of Biologically Active Ultrashort Peptides Using POT and LAT Carriers.
- 10.Peptide Regulation of Gene Expression: A Systematic Review.
- 11.Peptide Regulation of Cell Differentiation.
- 12.Neuroepigenetic Mechanisms of Action of Ultrashort Peptides in Alzheimer's Disease.
14 listed here; entry last updated August 2026
Reviews
My notesprivate to this device
FAQ
Does Testagen raise testosterone?
Nobody has measured it. No study in any species has taken an androgen reading after giving this peptide, so there is nothing to report either way.
Which findings are human and which are animal?
Every whole-animal result is in birds; five studies in hypophysectomised chickens and hens. The human work is cell culture only, showing the peptide entering the nucleus of cultured cells. There is no study in a living person.
Why is it called Testagen then?
The family names each peptide for the tissue its parent extract came from. Here the name and the experiments point at different organs; the experiments are all pituitary and thyroid.
Is there any human research?
None. No trial, no case report, no pharmacokinetics. A registered trial does exist under the same trade name, but it is a transdermal testosterone spray and unrelated to this peptide.
Is it safe?
Unknown, and the honest reason is that nobody has looked. The one repeated animal finding is a rise in thyroid hormones, which is worth knowing about for anyone with a thyroid condition.
Limitations of the evidence
- ALL whole-animal work is in birds, in a hypophysectomy model with no human counterpart [2][3][4][5][6]. No human study of any design exists, and no clinical trial has been registered
- The male reproductive description traces to two review tables rather than to an experiment; one carries no citation [9] and the other cites three papers about wheat histones, immune differentiation and two different peptides [7][10][11]
- No independent replication of any biological effect; the only unaffiliated paper is about copper corrosion [13]
- No pharmacokinetics at all, and the transporter work is docking scores with no transport measured [8]
- DNA and histone binding is fluorescence quenching only, and the histones tested were from wheat [1][7]
Adverse effects
- Unknown in humans; nothing has been systematically looked for
- Raises TSH, T3 and T4 in animals, so it is not inert alongside thyroid disease or thyroid medication [2][3][4]
- One animal study reported changes in coagulation and fibrinolysis, never followed up [5]
Notes and cautions
- The literature calls this an anterior pituitary peptide. The shop calls it a testis peptide. The two have never been reconciled in print
- NCT02733133, "Testagen TDS-Testosterone", is a transdermal testosterone spray from an unrelated company. Shared trade name, different product, and the likeliest source of a false human-evidence claim
- "Testoluten" is a different marketed name and returns nothing in PubMed; it is not an alias for this peptide