Thymogen is one of the smallest peptides you'll see discussed as an immune agent: just two amino acids, L-glutamic acid joined to L-tryptophan. Its systematic name is L-glutamyl-L-tryptophan (Glu-Trp), and PubChem lists it under the formula C16H19N3O5 with the CAS number 38101-59-6. Outside Russia it is better known by its drug-development name, oglufanide (the disodium salt, oglufanide disodium, was the form taken into Western trials).
The origin story is unusually concrete for a research peptide. Soviet researchers fractionated a calf-thymus extract called thymalin and screened the tryptophan-containing dipeptides inside it; Glu-Trp came out as the most active fraction. After preclinical and clinical work it was registered as the drug Thymogen in the USSR around 1990, and it carries a current Russian Ministry of Health registration certificate. It sits in the broader group of so-called Khavinson peptides and is sold there in injectable, nasal-spray, and topical-cream formulations.
Proposed mechanism
Thymogen is described as an immunomodulator rather than a straightforward stimulant — the claim is that it pushes a depressed immune system up and a hyperactive one down. A 2024 review in Pharmaceuticals (PMC11084461) reports that the peptide restores T-lymphocyte numbers in lymphoid organs and stimulates cellular and humoral immune reactions, and proposes that it acts at the level of chromatin, binding DNA and helping switch inactive regions into transcribable forms. That same paper makes a genuinely interesting point: the mirror-image molecule, D-Glu-D-Trp (marketed as Thymodepressin), does the opposite and suppresses immunity. Same atoms, opposite handedness, opposite effect.
In oncology the interest was different. The Western developers framed oglufanide as an antiangiogenic agent that lowers vascular endothelial growth factor (VEGF), which in principle could starve tumors of blood supply.
What the clinical evidence shows
This is where expectations need calibrating. The compound has a real Western clinical record, and it is mostly negative or inconclusive for the cancer indications.
- A published Phase II trial of intranasal IM862 (oglufanide) in 25 patients with metastatic renal cell carcinoma reported no objective responses; 8 patients had stable disease and the rest progressed, with a median time to progression of about 1.9 months. Plasma VEGF did fall measurably, which the authors read as a biological signal worth exploring in combination rather than as a working single agent. The full report is in the British Journal of Cancer (PMC2409952).
- It was later picked up for chronic hepatitis C: an Australian company, Implicit Bioscience, acquired the molecule in 2005 and ran early-phase trials of intranasal and subcutaneous oglufanide disodium in HCV, per a BioSpace release. It never became an approved hepatitis C therapy, and the field has since moved to direct-acting antivirals.
Much of the supportive immunology and anti-aging work is preclinical. The widely cited finding that L-Glu-L-Trp slowed aging markers and reduced spontaneous tumor incidence comes from a rat study, not from humans. Treat animal results as animal results.
So the honest summary: a registered drug in Russia with decades of use claims behind it, a documented but unsuccessful run through Western oncology trials, and early hepatitis C work that didn't reach approval. DrugBank tracks oglufanide disodium as an investigational salt. It is not an FDA- or EMA-approved drug.
For buyers and the quality angle
Material sold to labs as "Thymogen" or "oglufanide" is a research chemical, not approved for human consumption, and nothing here is medical or dosing advice. Because this is a tiny, achiral-looking dipeptide, the practical quality questions are identity and purity: is the vial actually L-Glu-L-Trp at the stated amount, and not a contaminated or mis-synthesized batch? A few points worth checking against any independent rating peptideone.org aggregates:
- A current, batch-specific certificate of analysis (COA) with mass-spec identity and an HPLC purity figure.
- Whether the stereochemistry is specified — the L,L form is Thymogen; the D,D enantiomer is a different, opposite-acting molecule.
- Third-party testing rather than vendor-only numbers.
WADA note: Glu-Trp is not a named substance on the WADA Prohibited List, but "not specifically listed" is not the same as "permitted," and athletes should verify status directly with their anti-doping authority before assuming anything.