D tier · weak
Uniquely in this family, the same molecule was developed in the West as oglufanide disodium / IM-862 and tested in registered trials — and it failed: a phase 3 study concluded IM-862 ‘is ineffective against AIDS-Kaposi's sarcoma’ after phase 1/2 had suggested a 36 percent response rate, and a phase 2 in metastatic renal cell carcinoma produced no objective responses in 25 evaluable patients. That is a defining trial that failed, on top of which none of the organ-specific epigenetic or geroprotective bioregulator claims has ever been tested in humans.
thymagen
Thymagen, more usually Thymogen, is the dipeptide L-glutamyl-L-tryptophan, isolated from thymus extract in Leningrad in the 1980s and registered in Russia as an immunomodulator in injectable, nasal-spray, topical and oral forms under the international name alpha-glutamyl-tryptophan. The identical molecule was licensed into Western development as oglufanide disodium (IM-862), received FDA orphan-drug designation for ovarian cancer in 2001, reached phase 3 in AIDS-related Kaposi's sarcoma and was found ineffective, after which development was abandoned. The peptide sold to researchers as ‘Thymagen’ is therefore the best-tested compound in the Khavinson family and also the one with the clearest negative result.
// we supply this one
available as a research reagent
≥ 98% HPLC · lyophilised powder · batch certificate published. Grade D above is our own and is not adjusted because we stock it.
the explanation
Thymagen is a two-amino-acid peptide from thymus tissue. It is a licensed immune medicine in Russia, and — unusually — the same molecule was taken into proper Western trials under a different name, IM-862. Those trials did not work out: a large late-stage cancer study concluded it was ineffective and the drug was dropped. So this is not an untested compound; it is a tested compound that mostly failed.
regulatory status
Registered medicine in Russia; failed Western development; unapproved and research-only in the UK
Alpha-glutamyl-tryptophan is a registered active substance in Russia, appearing in Thymogen solution for intramuscular injection and Thymogen metered nasal spray and topical cream (all Cytomed, ATC L03AA), in the oral gel product Regastim Gastro, and as a component of the combination product Cytovir-3. In the US and EU it has no approval: as oglufanide sodium it reached phase 3 and was discontinued, having received FDA orphan-drug designation for ovarian cancer in September 2001. It has no UK marketing authorisation, is not a controlled drug, and is not an authorised food-supplement or novel-food ingredient in Great Britain, so it is lawfully supplied here only as a research reagent; oral ‘thymogen’ supplements sold in the US are marketed under a different regulatory regime. Glu-Trp is not named on the WADA Prohibited List, though WADA's S0 unapproved-substances class is drafted broadly enough to cover it in competition.
how it works · proposed mechanism
Two incompatible mechanistic accounts exist for the same dipeptide. Western developers pursued it as an antiangiogenic and immunomodulatory small peptide; the St Petersburg group presents it as an epigenetic regulator of thymic gene expression. Only the first was ever tested against clinical endpoints.
Non-specific immunomodulation
Russian work reports interferon induction, altered cytokine secretion and modulation of ICAM-1 surface expression in vitro, which underpins the registered indications in recurrent respiratory infection and secondary immunodeficiency. These are laboratory-marker effects; the registered indications were not established by trials meeting contemporary Western standards.
Antiangiogenesis via VEGF — the tested hypothesis
IM-862 was developed as an angiogenesis inhibitor, and the phase 2 renal-cell-carcinoma study did report a fall in VEGF levels. It produced no objective responses in 25 evaluable patients, with a median time to progression of 1.9 months, and the authors concluded it should not be pursued as a single agent.
Stereochemical inversion
The D-isomer analogue of this dipeptide is registered in Russia as Thymodepressin and behaves as an immunosuppressant rather than an immunostimulant, a reciprocal-activity relationship described by Deigin and colleagues in 2024. This is a genuine and interesting pharmacological observation, and it also means chirality is a critical quality attribute for any material sold under this name.
Claimed epigenetic gene regulation
The Khavinson framework places Glu-Trp among ultrashort peptides that enter the nucleus and bind promoter regions to switch tissue-specific genes on or off, supported by molecular docking and experiments in stimulated human mononuclear cells. No human study has ever measured target engagement, and it is a very large claim for a two-residue molecule with no receptor and no characterised transporter-dependent nuclear delivery in vivo.
what’s reported
evidence shape
7 sourcesThe composition of the cited literature by study type. This describes the shape of the evidence, not its quality — and it does not by itself set the grade.
⚠ the catch
This compound's Western history is the fact vendors omit. Under the names oglufanide disodium and IM-862 the same Glu-Trp dipeptide went through registered trials in ovarian, colorectal and renal cancer and AIDS-related Kaposi's sarcoma; the phase 3 Kaposi's sarcoma trial concluded it was ineffective despite a 36 percent response rate in phase 1/2, the phase 2 renal-cell study produced zero objective responses in 25 patients, a phase 2 colorectal study was terminated because the drug was no longer available, and development stopped. Separately, the product name ‘Thymogen Alpha-1’ invites confusion with thymosin alpha-1, a genuinely different 28-residue peptide approved in several countries; the vendor's own copy confirms it is simply Glu-Trp plus Lys-Glu and ‘distinct from thymosin alpha 1 in both structure and origin’. Finally, Thymogen is one of the two dipeptides the originating group names as the active substances of Thymalin, so its bioregulator evidence base is shared with the Thymalin and Vilon entries and must not be counted three times.
key published findings
- PubChem CID 100094 confirms Glu-Trp as C16H19N3O5, 333.34 g/mol, CAS 38101-59-6, and lists Thymogen, Timogen and Oglufanide as synonyms of the same compound — the identity link between the Russian medicine and the Western investigational drug is a database fact, not an inference.
- Noy and colleagues, Journal of Clinical Oncology 2005: ‘Angiogenesis inhibitor IM862 is ineffective against AIDS-Kaposi's sarcoma in a phase III trial’, following an apparent 36 percent response rate in phase 1/2 studies.
- Deplanque and colleagues, British Journal of Cancer 2004: phase 2 in metastatic renal cell carcinoma, 25 evaluable patients, no objective responses, 8 with stable disease and 17 progressing, median time to progression 1.9 months; the authors advised against further single-agent evaluation.
- ClinicalTrials.gov lists three oglufanide studies — NCT00003773 (phase 1, recurrent ovarian cancer, 43 participants), NCT00017303 (phase 2, resected stage III ovarian/primary peritoneal) and NCT00006037 (phase 2, metastatic colorectal, 18 participants, terminated because the drug was not available).
- NCATS Inxight records oglufanide sodium as having reached phase 3 with development discontinued, holding FDA orphan-drug designation for ovarian cancer from September 2001, and notes it ‘originally was developed and registered in Russia under the brand name timogen’.
- Russian registration is broad: alpha-glutamyl-tryptophan appears in Thymogen injection, nasal spray and cream, in Regastim Gastro oral gel and in the Cytovir-3 combination, all from Cytomed, under ATC L03AA.
limitations of the evidence
- The registered Western trials were all in oncology and all negative or abandoned; none tested the immune, geroprotective or organ-regulatory claims for which the peptide is sold to researchers today.
- No registered trial exists under the names Thymogen or Thymagen, and the Russian registered indications are supported by literature that has never been independently reviewed outside Russia.
- The organ-specific epigenetic mechanism rests on molecular docking and cell culture from the originating group; there is no human pharmacokinetic, bioavailability or target-engagement data for a two-residue peptide claimed to act inside the nucleus.
- ‘Thymogen alpha-1’ is a supplement blend of Glu-Trp and Lys-Glu, not thymosin alpha-1, and not a distinct molecule; treating literature on thymosin alpha-1 as relevant to it is a category error.
- Evidence is shared with Thymalin and Vilon by the originating group's own account, so claims for the dipeptide, the extract and the sibling dipeptide are not three independent lines of support.
- Stereochemistry matters here — the D-isomer preparation Thymodepressin is an immunosuppressant — yet research-grade material is generally sold without published chiral-purity data.
documented safety signals
- Tolerability in the Western trials was good: the phase 2 renal-cell-carcinoma study recorded no grade 2 or 3 drug-related toxicities, which is the strongest human safety statement available for any compound in this family.
- That reassurance is bounded — it covers intranasal administration in small oncology cohorts, not long-term use in healthy people, for which no controlled safety data exist.
- The existence of an immunosuppressant D-isomer means stereochemical impurity in unregulated material could in principle invert the intended immunological effect; no vendor chiral-purity data was located.
- Research-grade material has no regulator-audited manufacturing standard, leaving impurity, endotoxin and enantiomeric content unquantified.
identity
| full name | Thymagen / Thymogen (L-glutamyl-L-tryptophan, Glu-Trp) |
| category | Other |
| modality | peptide |
| formula | C16H19N3O5 |
| molar mass | 333.34 g/mol |
| cas | 38101-59-6 |
| sequence | Glu-Trp (EW) |
laboratory handling
| storage | Lyophilised powder is stored desiccated at -20 °C and protected from light. Once reconstituted, laboratory practice is refrigeration at 2-8 °C for short-term use, or aliquoting and freezing to avoid repeated freeze-thaw cycles. Handling information only; this material has no approved human use. |
| solubility | Short hydrophilic peptide, readily soluble in sterile or bacteriostatic water and in dilute aqueous buffer. Lot-specific solubility is stated on the certificate of analysis. |
| co-studied with | Glu-Trp and Lys-Glu are routinely sold together as an ‘immune’ pairing, which mirrors the originating group's claim that both are the active constituents of Thymalin; combining them therefore duplicates one hypothesis rather than testing two, and no combination study with a clinical endpoint has been registered. |
Handling information describes laboratory practice for a research reagent. It is not a preparation guide for use in humans.
the receipts
7 citedPubChem, US National Library of Medicine · 2026 · official
NCATS Inxight Drugs, US National Center for Advancing Translational Sciences · 2026 · official
ClinicalTrials.gov, US National Library of Medicine · 2026 · official
Vidal Russia medicines reference · 2026 · official
Journal of Clinical Oncology · 2005 · randomized
British Journal of Cancer · 2004 · clinical study
Journal of Clinical Oncology · 2000 · randomized
others in Other