Testagen: What It Is, Dosage and What the Evidence Shows

Testagen is one of the Khavinson-group peptide bioregulators, sold as a “testes bioregulator” for testosterone and reproductive support. The published studies of its sequence measure something else: the thyroid and thymus, in birds.

What is Testagen?

Testagen is a synthetic tetrapeptide: four amino acids, Lys-Glu-Asp-Gly (lysine-glutamic acid-aspartic acid-glycine). It comes from the St Petersburg peptide-bioregulator programme described on the bioregulator hub page. Vendors market it for testosterone, fertility and reproductive-system support.

Testagen structure

Molecular formula

C₁₇H₂₉N₅O₉

Molecular weight

447.4 g/mol

Length

4 amino acids

Sequence

KEDG

Modifications

Lys-Glu-Asp-Gly; free N- and C-termini; all L-amino acids.

PubChem CID

123863700

Identity checked against Fedoreyeva et al., Biochemistry (Mosc) 2011.

How Testagen works

The bioregulator theory proposes that short peptides like this one act on gene activity in specific tissues, as described on the bioregulator hub page. That is a hypothesis for the whole class, not a testes-specific finding for this compound.

Testagen benefits: what the research shows

I couldn’t find any PubMed-indexed study naming “Testagen” or testing it on testicular tissue, sperm or testosterone. What does exist, from the group that first described the sequence, is a set of studies in young and old birds with the pituitary gland removed:

• Thymus: Lys-Glu-Asp-Gly partly restored thymus structure disrupted by removing the pituitary. It worked better than a second peptide tested alongside it, Ala-Glu-Asp-Gly Pateyk 2013 - Pateyk AV, Baranchugova LM, Rusaeva NS et al. Effect of peptides Lys-Glu-Asp-Gly and Ala-Glu-Asp-Gly on the morphology of the thymus in hypophysectomized young and old birds. Bull Exp Biol Med. 2013;154(5):681-5., in the references below.
• Thyroid: giving the same two peptides for 40 days significantly reduced the hormonal and structural thyroid damage caused by pituitary removal in young chickens. The effect was smaller in old hens Kuznik 2011 - Kuznik BI, Pateyuk AV, Rusaeva NS et al. 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. Bull Exp Biol Med. 2011;150(4):495-9., in the references below.

Testagen dosage

Dosing guides most often describe an oral course of roughly 10-20 mg once daily, for 10-20 days, repeated every 3-6 months. That is common practice reported by online guides, not a dose any trial or regulator has set.

Some sources describe an injectable version (under the skin or into muscle), but they disagree with each other by about a hundredfold: the figures I found ran from about 100 mcg to 10 mg per day. This page doesn’t give a dose for that route.

Common protocol

What is commonly used, not a dose established in trials. No regulator has set a dose for Testagen.

Dose

10-20 mg

How often

once daily by mouth

Route

By mouth

Cycle length

1.4-2.9 weeks

Break between cycles

13-26 weeks

Timing

Once daily; sources describing this route do not agree on morning versus evening.

Sources describing an injectable (subcutaneous or intramuscular) form of Testagen exist, but the doses they state for that route range from about 100 mcg to 10 mg per day - a roughly hundred-fold spread with no two sites agreeing closely enough to state one number, so this record reports only the oral course, where two sources agree reasonably well.

Plan a cycle in the protocol builder

What is not established

• No study of any kind (cell, animal or human) exists under the name “Testagen.”
• The animal studies of its exact sequence measured the thyroid and thymus, not testicular function or testosterone, in birds with the pituitary surgically removed.
• No dose has been shown safe or effective for any use by any regulator.
• Sources disagree by about a hundredfold on the injectable dose, so only the oral course, where two sources broadly agree, is given above.

Testagen side effects

No published human or animal safety study exists for Testagen at any dose, so there is no verified side-effect rate. It is sold as a research chemical or an unregulated capsule or vial product, and no regulator checks that a batch matches its label. Because an injectable form is also sold, see peptide injection-site reactions for the general risks of injecting under the skin, which are not specific to this compound.

Is Testagen legal?

Testagen is not approved for human use by the FDA or any regulator I can verify. It is sold internationally as a research chemical or an unregulated capsule or vial product, outside any approved drug supply chain.

Regulatory changes for this compound and others, as they happen: US peptide regulation tracker.

Related

• Peptide bioregulators: the Khavinson peptides
• Epitalon
• Pinealon
• Research peptides and the law

How Testagen compares

Bioregulators. Doses for unapproved compounds are common practice, not trial-established. All bioregulators peptides →

Compound	Main use	Evidence	Usual dose	US status
Testagen	Marketed for testosterone and reproductive-system support, sold as a "testes bioregulator."	Animal / lab only	10-20 mg, once daily by mouth	Research use only
Epitalon	Sold for longevity and anti-aging on the basis of telomere research.	Animal / lab only	5-10 mg, once nightly, every night, for the length of the cycle	Research use only
Pinealon	Sold for cognition, focus and healthy aging.	Limited human data	1-2 mg, once daily, morning preferred; some protocols run 5 days a week rather than every day	Research use only
Cartalax	Marketed for cartilage and joint support, sold as a "cartilage bioregulator" for age-related joint wear.	Animal / lab only	200 mcg, once daily	Research use only
Vilon	Marketed as a thymus and immune-system bioregulator, sold for immune support and healthy ageing.	Animal / lab only	10-20 mg, once daily by mouth	Research use only
Vesugen	Marketed as a vascular-tissue bioregulator for cardiovascular and blood-vessel aging; more recent papers from the same research group also study it as a candidate for age-related cognitive decline.	Limited human data	500-5000 mcg, once daily, subcutaneous, commonly started low and titrated upward over the first 1-3 weeks	Research use only
Cardiogen	Marketed as a heart-tissue bioregulator for cardiovascular aging, from the Khavinson organ-specific peptide programme.	Animal / lab only	200-2000 mcg, once daily, subcutaneous, most commonly cited around 1 mg/day	Research use only
Prostamax	Marketed as a prostate-tissue bioregulator for age-related prostate change, from the Khavinson organ-specific peptide programme.	Animal / lab only	750-2000 mcg, once daily, subcutaneous, often started lower and increased after 1-4 weeks	Research use only

Where to buy Testagen for research

Each vendor is checked against my vendor checklist.

1. 1.BioEdge Research Labs

   20 mg vial

   • No FDA warning letter found
   • Names its testing lab
   • Batch COAs published

   $59.00as of 3 October 2026

   View product →My BioEdge Research Labs review

See all vendors and how they compare →

Common questions

Is there any published research on Testagen specifically?

Not under that name: a PubMed title/abstract search for "Testagen" returns only two papers, neither about this peptide. Searching by its sequence, Lys-Glu-Asp-Gly, finds real animal studies from the originating group. They measured thyroid and thymus outcomes in chickens with the pituitary removed (hypophysectomised), not testicular function.

What is the usual Testagen dose?

Dosing guides most often describe roughly 10-20 mg by mouth once daily, in a 10-20 day course repeated every 3-6 months. That is common practice, not a dose any trial or regulator has set. Sources on an injectable version disagree with each other by about a hundredfold, so this page doesn't give an injectable figure.

What are the side effects of Testagen?

No published human or animal safety study of this compound exists at any dose, so there is no verified side-effect rate. See the side effects section for what is and isn't known.

References (2 sources)

Show

Bibliographic detail is fetched from PubMed, not written by me - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than my judgement.

1. 1.Pateyk AV, Baranchugova LM, Rusaeva NS et al. Effect of peptides Lys-Glu-Asp-Gly and Ala-Glu-Asp-Gly on the morphology of the thymus in hypophysectomized young and old birds. Bull Exp Biol Med. 2013;154(5):681-5.StudyPMID 23658898
2. 2.Kuznik BI, Pateyuk AV, Rusaeva NS et al. 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. Bull Exp Biol Med. 2011;150(4):495-9.StudyPMID 22268052

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