Thymogen
Glu-Trp Immune Dipeptide
Evidence grade 1 of 5, Untested. Read how the Atlas grades evidence.
Thymogen (L-glutamyl-L-tryptophan) is a synthetic thymic dipeptide registered and used as an immunomodulator in Russia since 1990, developed by Khavinson and colleagues, but its human evidence base is essentially confined to Russian-language reports and animal/in-vitro work with no Western RCT replication. The most rigorous Western human data come from SciClone's closely related gamma-D-isomer SCV-07 (gamma-D-Glu-L-Trp), whose controlled Phase 2 programs in chronic hepatitis C and in chemoradiation-induced oral mucositis both failed to show efficacy, so the honest grade for the marketed immune-support use is animal-and-registration-level, not RCT-supported.
- FDA
- Not FDA approved. Registered in Russia in three formulations (IM injection, nasal spray, topical); marketed in the West only as a research chemical.
- WADA
- Not prohibited
Reference only. Not medical advice.
What can go wrong
Registered and used only in Russia; no successful Western RCT replication for the L-isomer, and the related D-isomer SCV-07 failed controlled Phase 2 trials. Sold in the West as a research chemical not for human use.
Talk to a clinician before taking this. The Atlas can tell you what has been studied about Thymogen. It cannot tell you how it would interact with your body, your history, or anything else you are taking, and nothing on this page is a reason to start.
A synthetic immune dipeptide developed in Russia, approved there as an immunomodulator for infections and immune deficiency. Among the simplest bioactive peptides, just two amino acids.
What people take it for
These are the reasons people give for taking it. They are not effects it has been shown to have.
How it is supposed to work
Thymogen is a synthetic dipeptide (glutamic acid and tryptophan) derived from thymic peptide work, used as an immune modulator, particularly for respiratory infections and recovery after illness. It is one of the defined synthetic Cytogen peptides rather than a tissue extract.
Thymogen is a synthetic dipeptide, glutamic acid and tryptophan, derived from work on the immune-active fragments of thymus peptides. It is a defined-sequence bioregulator and a sibling to the other immune peptides Vilon and the natural extract Thymalin.
- Type
- Synthetic dipeptide
- Sequence
- Glu-Trp
- Target
- Immune system
- Use
- Injection or nasal, Russia
- Evidence
- Russian clinical
- Western RCT
- Limited
A Dipeptide Immunostimulant, Russian-Approved, Western-Unverified
Thymogen sits a notch closer to conventional pharmacology than some of its relatives, because it has a defined sequence, a described immunostimulant action, and a history as a registered Russian medicine rather than purely a longevity product. That said, the familiar caveat holds. The supporting evidence is overwhelmingly Russian and tied to the originating research environment, with little independent Western validation, and the broad immune claims attached to it on the gray market run ahead of what rigorous trials have shown. It is a real, regionally used immune peptide whose effects the wider evidence base has not confirmed, and whose marketing often overstates a modest and narrowly studied medicine.
Safety in detail
Russian-registration literature reports Thymogen as well tolerated with few reported adverse effects, though this rests on Russian post-marketing use rather than Western controlled safety datasets. Western supply is research-chemical grade with no regulated purity or human-use assurance.
- Reported safety in decades of Russian clinical use is described as clean, with few serious adverse events, but that record comes largely from within the same research tradition that developed the peptides and has not been independently verified in Western trials.
- Long-term safety in rigorous, controlled human studies is essentially uncharacterized outside that tradition.
- Most material sold internationally is gray-market or supplement-grade, so unverified identity, dose and purity are the dominant practical risks.
- Not FDA-approved for any use; claims of disease treatment are not supported by Western regulatory review.
Children and teenagers
Thymogen has limited Russian pediatric use under medical supervision but is unapproved elsewhere, with no appropriate self-directed pediatric use.
What people get wrong
Nothing recorded here yet. There is almost certainly something people get wrong about this one, and the blank space means we have not written it down, not that the record is clean.
Who profits, and who pushes back
Nobody is named here yet, because we have not done that work on this entry. Read that as unfinished. Somebody almost certainly sells this, and somebody almost certainly disputes it. Assume both until we have checked.
Thymogen is a marketed product in Russia and reaches Western users through import and the bioregulator gray market. Its economy mixes regional pharmacy use with longevity-vendor sales, both ahead of independent proof.
How we got here
Thymogen is a synthetic dipeptide immunomodulator (alpha-L-glutamyl-L-tryptophan) developed in Russia and registered there as an intranasal spray and injectable for secondary immunodeficiency. Its structure is the naturally occurring L,L-isomer of the Glu-Trp sequence found in thymic peptide hormones. It is closely related to the gamma-D-glutamyl-L-tryptophan isomer SCV-07 (golotimod), which SciClone Pharmaceuticals advanced in Western clinical trials for oral mucositis and hepatitis C before discontinuing development after those studies failed to meet efficacy endpoints.
Thymogen came out of Soviet and Russian work on immune-active thymus peptide fragments and was developed into a registered short-peptide immune medicine, alongside the related Vilon and the Thymalin extract.
The numbers behind the grade
- Type
- Dipeptide (Glu-Trp)
- Target
- Immune system
- Russia
- Registered pharmaceutical
- FDA
- Not approved
- Use
- Respiratory/immune
- Western RCTs
- None
The people taking it
A well-known immune bioregulator, notable for being one of Khavinson’s registered Russian pharmaceutical products.
Thymogen’s users are patients in Russia using it for immune support, plus immune-focused biohackers and the bioregulator-protocol community abroad.
Used in Russia as a registered immunomodulator and internationally as an immune-support bioregulator. Its evidence is largely from the originating tradition.
Set against the alternatives
Thymogen is the registered-medicine sibling of the longevity-framed immune dipeptide Vilon, and a synthetic relative of the Thymalin extract. Against thymosin alpha-1, the internationally approved immune peptide, Thymogen is the narrower, regionally studied analogue. Within the family it is one of the more conventionally drug-like entries, which makes its thin independent evidence all the more notable.
What we do not know
- Whether independent, Western randomized trials confirm any of the claimed clinical effects.
- Whether the proposed DNA-binding, gene-regulating mechanism actually operates in human tissue at the doses used.
- Why, after forty years and hundreds of papers, replication outside the originating institute remains so limited.
- Whether results from complex tissue extracts (Cytomaxes) translate to the defined synthetic peptides (Cytogens) sold alongside them.
Legal status
Not FDA-approved for any indication in the United States. Several related bioregulators are registered pharmaceuticals in Russia, where they are used clinically, but that approval does not carry to the US or EU. The first formal FDA advisory-committee evaluation of a Khavinson peptide (Epitalon) is scheduled for July 2026. Internationally it is sold as a Cytogen or Cytomax supplement and as a research chemical.
Status current as of July 2026. Regulatory positions change, sometimes quickly.
The market for this
What follows describes how this is bought and sold. It is not a buying guide and it is not an endorsement of any seller.
Available internationally as oral or injectable bioregulator supplements (Cytogen and Cytomax lines) and as research-use-only peptide vials, with legal status varying by country. None is an FDA-approved medicine, so there is no regulated US prescription route; the honest course is to treat the claims with caution and consult a clinician.
Material reaches international buyers two ways: as branded Cytogen (synthetic) or Cytomax (animal-tissue extract) supplements produced in Russia, and as research-use-only vials, much of it synthesized in China. Neither route guarantees the identity or potency the label claims, so an independent certificate of analysis is the only real check and is uncommon.
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Thymogen.
- Timeline. We have not built the dated record of research and regulatory events.
- Supply chain. We have not mapped where it is made.
- What could change. No forward-looking summary yet.
Sources
Thymogen is the synthetic dipeptide L-glutamyl-L-tryptophan (Glu-Trp/EW) isolated from thymalin and developed as an immunomodulator; overview of thymic peptide pharmaceuticals.
Khavinson bioregulator peptides including Glu-Trp/thymogen and thymalin; chromatin/gene-expression proposed mechanism and immune-differentiation effects.
The immunomodulatory gamma-D-glutamyl-L-tryptophan (SCV-07), the D-isomer analog of thymogen, is used to attenuate radiation-induced oral mucositis; stimulates T-lymphocyte differentiation and IL-2/interferon in mice.
SciClone's Phase 2 SCV-07 oral mucositis interim analysis: all three dosage arms showed no efficacy relative to primary or secondary endpoints, and the DMC recommended discontinuing enrollment.
SCV-07 (gamma-D-glutamyl-tryptophan) failed in a mid-stage chronic hepatitis C study; SciClone discontinued development in that indication.
BioSpace, SciClone Drug SCV-07 Fails In Mid-Stage Hepatitis C Study
Design and structure of the Phase 2b randomized, double-blind, placebo-controlled SCV-07 oral mucositis study in head-and-neck cancer patients.
BioSpace, SciClone Initiates Phase 2b Study of SCV-07 for Treatment of Oral Mucositis
Topline Phase 2b hepatitis C results and program status for SCV-07, the D-isomer glutamyl-tryptophan immunomodulator.
Thymogen animal-model protective data (D-alanine-modified analogues in hydrazine liver damage), illustrating that the supportive evidence base is preclinical/animal.
Commercial vendors market Thymogen/Thymagen (Glu-Trp) explicitly as a research chemical not approved for human use in the West, confirming research-chemical status.
The studies that matter
Khavinson group clinical work1980s-2000s
Reported immunomodulatory effects in respiratory and post-illness settings, and registration as a pharmaceutical in Russia.
Independent replicationlimited
Defined as a simple dipeptide, but rigorous independent Western efficacy trials are lacking.