Testagen

Overview

Testagen is a synthetic tetrapeptide (Lys-Glu-Asp-Gly / KEDG) from the Khavinson bioregulator series, claimed to target testicular tissue. Not FDA-approved. Evidence base is extremely thin, with essentially no independently replicated or peer-reviewed support for the advertised reproductive or endocrine benefits in humans.

Mechanism of Action

Proposed mechanism per the Khavinson model: the peptide penetrates cell cytoplasm and nucleus and preferentially binds CAG-containing DNA sequences in vitro. Specific effects on Leydig-cell StAR or CYP11A1 expression remain hypothetical and are not supported by replicated peer-reviewed studies.

Research Summary

Evidence is extremely limited. Fedoreyeva et al. (Biochemistry [Moscow], 2011; PMID 22117547) — from Khavinson-group collaborators — showed that fluorescently labeled Lys-Glu-Asp-Gly (testagen) penetrated HeLa-cell cytoplasm and nucleus and bound CAG-containing deoxyribooligonucleotides in vitro. No replicated Leydig-cell, animal, or human clinical-trial data has been published in indexed peer-reviewed literature. Reproductive or steroidogenic benefits in humans have not been demonstrated.

Dosing Information

Reported Side Effects

• Limited human safety data
• Injection site irritation (preclinical)
• No significant adverse effects in published preclinical studies
• Potential hormonal fluctuation with repeated dosing (theoretical)

Research References

• Penetration of short fluorescence-labeled peptides into the nucleus in HeLa cells and in vitro specific interaction with DNA (Fedoreyeva, Kireev, Khavinson, Vanyushin) (2011)