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Thymogen

Also known as Timogen, Glu-Trp, EW dipeptide, oglufanide, IM862

Synthetic thymic dipeptide registered in Russia; the same molecule failed Western cancer trials as oglufanide.

early-clinical Immune & longevity approved drug

At a glance

Category
Immune & longevity
Status
approved drug
Route
intramuscular injection, intranasal spray and topical cream in the registered Russian presentations; intranasal in the IM862 oncology trials
Half-life
No published human pharmacokinetics for the Russian preparation. A free dipeptide with no protecting modifications is a substrate for ubiquitous plasma and tissue peptidases, so survival in circulation is presumably a matter of minutes at most. Any half-life figure offered by a supplier has no primary source.
Molecular weight
333.3 g/mol
Sequence
Glu-Trp (EW), L-configuration

Thymogen (L-Glu-L-Trp) has been registered in Russia since around 1990 as an immunomodulator, reportedly in three presentations: a solution for intramuscular injection, a metered nasal spray and a 0.05% topical cream. That registration rests on the Soviet and Russian approval procedure and has never been assessed by EMA or FDA. The identical molecule was separately developed in the West as oglufanide (IM862), which reached phase II and phase III oncology trials and was not approved - the Kaposi's sarcoma programme was discontinued 45, and a phase II trial in metastatic renal cell carcinoma was published in 2004 1. So the compound has both a national registration and a documented Western clinical failure, and the two facts belong together. What is sold online as 'Thymogen' is a research chemical, not the Russian pharmaceutical product.

Doping status: Not listed by name on the WADA prohibited list

Checked against the WADA 2026 Prohibited List. For a specific product and country, Global DRO is the lookup athletes are expected to use — the List names substances, not brand names.

This is a short entry. There is little or no published research on this compound, so there is correspondingly little to report. Empty dosing or reconstitution sections mean no credible figures exist — not that they were left out.

Mechanism of action

Thymogen was isolated by Khavinson and Morozov's group as the proposed active dipeptide fragment of Thymalin, the bovine thymus extract, and then produced synthetically. The claimed action is on T-lymphocyte maturation and differentiation and on normalising the balance between T-cell subsets - essentially the same claim made for the parent extract, transferred to a two-residue molecule. As with the rest of the Khavinson bioregulator programme, the underlying doctrine is that short peptides from an organ selectively restore that organ's function by influencing gene expression, and that premise of tissue specificity has never been independently established. A dipeptide of glutamate and tryptophan is chemically indistinguishable from ordinary protein digestion products present throughout the body, which makes organ-selective targeting difficult to argue for.

The Western development route gave the molecule a different mechanistic story: as oglufanide/IM862 it was pursued as an antiangiogenic agent said to inhibit VEGF and to increase natural killer cell activity, which is why it was trialled in Kaposi's sarcoma and renal cell carcinoma 14. One noteworthy and well-documented property is stereochemical: the all-D enantiomer of the same dipeptide, marketed in Russia as Thymodepressin, is reported to be immunosuppressive rather than immunostimulatory. If correct, that is an unusually clean demonstration that the effect is stereospecific and therefore mediated by some chiral binding site - but the binding site itself has never been identified, and no receptor for Thymogen has been cloned or characterised.

What the research shows

Unusually for a Khavinson-programme compound, this one was tested in Western clinical trials - and did not succeed. The Russian registration rests on domestic trials that are largely not internationally indexed and cannot be independently assessed. There is modern in-vitro work showing anti-inflammatory activity in a monocyte cell line 2. There is no controlled evidence supporting the immune-support or anti-ageing uses for which it is sold online.

Research in humans

As oglufanide/IM862, the compound went through Western oncology trials. A randomised study of IM862 nasal solution in AIDS-related Kaposi's sarcoma was conducted, and a phase III programme in that indication was discontinued 4. A phase II trial in metastatic renal cell carcinoma (British Journal of Cancer, 2004) evaluated it as an antiangiogenic agent 1. It also entered phase II work in hepatitis C in Australia 4. None of these programmes led to approval. On the Russian side, registration for secondary immunodeficiency, post-radiation immune recovery and chronic infection rests on domestic clinical experience that is mostly published in Russian-language journals, is generally small and uncontrolled, and cannot be evaluated from outside. No Western randomised trial supports any immunodeficiency indication.

Animal and lab research

Rodent work from the originating group and affiliated laboratories reports effects on T-cell populations, on haematopoietic recovery after irradiation, and on natural killer cell activity. A paper on the optical and chemical isomers of the EW dipeptide examined effects on colony-forming units in intact and irradiated mice, which is the sort of experiment that underpins the stereospecificity claim. Independent replication outside this circle is sparse.

Caveats. The most informative single fact is that the molecule was taken through Western clinical development by a company with every incentive to make it work, and did not reach approval 4 - a discontinued phase III is meaningful negative information that marketing for 'Thymogen' never mentions. Russian registration reflects a national procedure of the early 1990s rather than a contemporary evidence standard. The mechanistic case rests on the same unestablished tissue-specificity doctrine as the rest of the programme, with no identified receptor. There is no published human pharmacokinetics, no dose-response study for the immunomodulatory indications, and no toxicology programme assessable from outside Russia. Grey-market material is of unverified identity - though a dipeptide is at least a synthesis simple enough that gross misidentification is less likely than with longer peptides.

What it is used for

  • Secondary immunodeficiency, chronic bacterial and viral infection, and immune recovery after radiation or chemotherapy - the registered Russian indications
  • Investigated and abandoned as an antiangiogenic agent in AIDS-related Kaposi's sarcoma 5 and metastatic renal cell carcinoma 1 under the name IM862/oglufanide
  • Investigated in hepatitis C without reaching approval 4
  • Sold on the grey market as a general immune-support peptide, an indication no controlled trial supports

Dosing

  • No dose is stated here as a recommendation. The Russian product information for the injectable is reported to use a 100 mcg/ml solution and for the nasal spray 25 mcg per actuation, with courses of several days; these figures come from product literature rather than from controlled trials, and the underlying registration dossier is not publicly assessable.
  • The IM862 oncology trials used intranasal dosing on their own schedules 15, which have no bearing on immune-support use and belong to a programme that did not succeed 4.
  • There is no dose-finding study, no maximum tolerated dose and no human pharmacokinetics for the immunomodulatory indications.
  • Note the enormous discrepancy in scale between the microgram doses in the Russian product literature and the milligram doses in grey-market protocols. Anyone dosing this in milligrams is exceeding the registered exposure by orders of magnitude with no basis for doing so.

These figures describe what the literature and published protocols report. They are not advice and not a dosing instruction.

Reconstitution

Storage
Lyophilised powder is stored refrigerated and protected from light; long-term storage at -20 °C. The Russian product information directs immediate use of the reconstituted solution.

No reconstitution protocol is given here, because there is no validated dose for the uses under which it is sold outside Russia and providing one would imply otherwise.

Safety

Side effects

  • The Russian reports and the oncology trial literature describe it as generally well tolerated 1, but the Russian data lack systematic safety monitoring and tolerability in cancer trials does not transfer to healthy users
  • Injection site reactions; local irritation with the nasal spray
  • Hypersensitivity reactions
  • Theoretical exacerbation of autoimmune disease through immune stimulation - not studied
  • No internationally assessable toxicology, carcinogenicity or reproductive toxicity programme has been published

Do not use if

  • Known hypersensitivity to the peptide
  • Autoimmune disease - immune stimulation is mechanistically undesirable here and has not been studied
  • Immunosuppression after organ transplantation
  • Pregnancy and breastfeeding - no data
  • Children outside the registered Russian indications and supervision

Interactions

Not systematically studied. Antagonism of immunosuppressive therapy is mechanistically plausible but undemonstrated. Given the reported opposite activity of the D-enantiomer (Thymodepressin) 3, co-administration of D- and L-forms would be pharmacologically incoherent, though nobody appears to have tested it.

Sources