Testagen

Also known as: KEDG, Lys-Glu-Asp-Gly

Evidence: Preclinical

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Overview

Khavinson-series synthetic tetrapeptide KEDG (Lys-Glu-Asp-Gly), described as pituitary-derived; studied for thyroid and thymus effects in hypophysectomized chickens. No testis study exists.

The name Testagen implies a testicular peptide, but no published study tested KEDG on the testis, sperm or testosterone. The developer group's 2022 table lists Testagen as KEDG (Lys-Glu-Asp-Gly) (Khavinson 2022); the old record stored KED, which is Vesugen. All animal work treats KEDG as a pituitary-derived peptide and comes from one group: in neonatally hypophysectomized chickens and old hens it was compared with AEDG (Epitalon) for effects on thyroid structure and hormonal activity, immunity, hemostasis and thymus morphology (Kuznik 2008, 2010, 2011; Pateyk 2013). Cell work showed short fluorescence-labelled peptides entering HeLa cell nuclei (Fedoreyeva 2011). No human trial has been published.

Benefits

Thyroid structure and hormonal activity in hypophysectomized chickens and old hens (avian), thymus morphology in hypophysectomized birds (avian), nuclear entry and DNA binding of short peptides (in vitro)

Dosing reference

Research dose: 200 to 1000 mcg daily: vendor/community range, no published human dose
Range: 200 to 1000 mcg, 1x daily

Sold as oral capsules and as lyophilized powder for injection. No published human dose or schedule; the bird studies are not a basis for one. Community protocols run 10 to 20 day courses two or three times a year; no study compared schedules.

Mechanism

Proposed by the developing group and never tested on reproductive tissue. Short fluorescence-labelled peptides of this series entered HeLa cell nuclei and bound DNA oligonucleotides in vitro (Fedoreyeva 2011), which the group reads as support for gene regulation by direct DNA binding (Khavinson 2020). Docking predicts uptake through PEPT and LAT family transporters (Khavinson 2022, 2023). The Leydig cell, steroidogenesis and HPG-axis claims in the old text had no source and were removed.

Evidence

Preclinical: animal or in vitro data only

In neonatally hypophysectomized chickens, KEDG and AEDG were tested for effects on thyroid structure and function (Kuznik et al., 2008)
In hypophysectomized young chickens and old hens, both peptides were studied for thyroid hormonal activity and structure, immunity and hemostasis (Kuznik et al., 2010, 2011)
Thymus morphology was examined in hypophysectomized young and old birds given KEDG or AEDG (Pateyk et al., 2013)
Short fluorescence-labelled peptides entered HeLa cell nuclei and bound DNA oligonucleotides in vitro (Fedoreyeva et al., 2011)
Human-trial status: none published. No study in any species tested testis, sperm or testosterone, and nearly all work comes from one group

References

Side effects

No controlled safety study has been published in any species; the bird and cell studies, all from the developing group, were not designed to detect harm. Commonly reported (anecdotal): injection-site irritation with injectable forms.

Storage

Storage: Room temperature
Lyophilized: 24+ months

Pharmacology

Half-life: No published pharmacokinetic data in any species
Bioavailability: Not measured in any species. Docking predicts transport by PEPT and LAT family carriers (Khavinson 2022, 2023)
Molecular weight: 447.44 Da
Sequence: KEDG (Lys-Glu-Asp-Gly)