Testagen is a synthetic 4-amino-acid peptide (lysine, glutamic acid, aspartic acid, glycine, often written KEDG) from the Russian group behind epitalon and pinealon.[1] It is sold in Russia as a dietary supplement for male reproductive health.[2] The published research on it is very thin: a few lab binding studies, some Russian chicken studies, and one short human report written by its developers.[3][5] We found no peer-reviewed human trial.

What is testagen?

Testagen is one of the “peptide bioregulators” developed by Vladimir Khavinson’s institute in St. Petersburg. A 2011 Russian paper named testagen as Lys-Glu-Asp-Gly.[1] The Russian supplement contains a peptide complex made of those four amino acids, 100 micrograms per 0.2 g capsule, and is made by Firma-Vita in Russia.[2] For how this peptide family was developed, see our guide to Khavinson peptide bioregulators.

One oddity: separate Russian chicken studies of the same sequence, from a group in Chita, describe KEDG as synthesized to match the amino acid makeup of extracts from the anterior pituitary gland, not the testes.[5][6] We could not find a published paper explaining how the testicular claim was established.

Testagen research: what exists

Lab studies

  • Getting into cells: fluorescent-labeled testagen entered the nucleus of human cancer cells in a dish, and in test-tube experiments it appeared to bind preferentially to certain DNA sequences.[1] It also bound to histone proteins from wheat.[4]
  • Transport: computer modeling suggested KEDG could fit into the transporters cells use to take up small peptides. This is a simulation, not a measurement.[9]
  • Immune cells: a developer review lists KEDG among peptides that stimulate immune-cell differentiation, without trial data.[8]

One of the few studies from outside Russia that names testagen tested it as a corrosion inhibitor for copper in salt water. It tells us nothing about its effects in the body.[10]

Animal studies

  • Chickens: in chickens whose pituitary gland was removed, 40 days of KEDG or epitalon raised thyroid-stimulating hormone and thyroid hormones and helped restore thyroid structure.[5] The effect was weaker in old hens.[6] KEDG also helped restore thymus structure, more so than epitalon.[7]
  • Rat testes (developer report): the developers say Testagen increased growth of testicular tissue from young and old rats by about 54% and 41% in culture, with no significant effect on 16 other rat tissues. In rats made sterile by radiation, treated animals regained some fertility while untreated ones did not. Group sizes are not reported, and doses are given only as “therapeutic” and 10 times that.[3]

Human data

The only human data we found are in a 2021 article by Khavinson and Ryzhak in a Russian drug reference, not a peer-reviewed journal.[3] It describes 48 men aged 54 to 68 with symptoms of age-related hormone decline. The authors say the men were randomized. All received standard care (tonics such as ginseng and deer-antler extract, vitamins and, if needed, sedatives or antidepressants), and 27 also took Testagen for 20 days. Their table shows average testosterone of 6.1 ng/mL before treatment, 6.5 ng/mL after standard care alone and 7.3 ng/mL with Testagen added, and they report better sperm count and motility.

Testagen vs epitalon

Both are four-amino-acid peptides from the same institute and differ only in the first amino acid: lysine in testagen, alanine in epitalon.[1] Epitalon has far more published research, including lifespan studies in animals; see our epitalon profile. For better-studied options aimed at male hormones, see our hormonal peptides and sexual health peptides pages.

Testagen dosage

No dose has been tested in a controlled trial. The Russian supplement listing suggests 1 to 2 capsules once or twice daily with meals for a month, repeated after 4 to 6 months.[2] Injectable vials sold online are research chemicals with seller-derived doses. Our peptide calculator explains vial math in general, but it cannot make an untested dose safe.

Testagen side effects

  • Not well studied. The developers report no toxicity in animal tests at doses far above the recommended one, and say they saw no adverse reactions in their human report, but these data have not been independently checked.[3]
  • Hormone effects: if testagen does change testosterone, LH or FSH, as the developers claim, it could affect fertility and other hormone-sensitive conditions. That has not been studied.
  • Product quality: testagen sold online as a research chemical is not checked by any regulator for purity, dose or sterility.

Questions to ask a clinician

Because there is no reliable human trial, a doctor cannot tell you what testagen will do. If you are considering it for low testosterone or fertility, it is worth asking:

  • Have my testosterone, LH and FSH been measured, and what is causing any low result?
  • Are there tested, approved treatments for my situation?
  • Could an unregulated product affect a fertility workup, or a drug test if I compete in sport?
  • Russia: sold as a dietary supplement, not a registered medicine.[2]
  • US: not FDA-approved, and not on any of FDA’s 503A bulk substance lists as of May 14, 2026.[11] It is also absent from FDA’s list of substances with significant safety risks.[12]
  • Sports: not named on WADA’s 2026 list, but as a substance with no government approval for human use as a medicine, in our reading it falls under the S0 category, which is banned at all times.[13]

This is general information, not legal advice.

What users report

We found no detailed user reports on forums we consider reliable. For other compounds promoted for healthy aging, see our longevity peptides page.