Thymogen

Thymogen (also marketed as Thymagen) is a synthetic dipeptide with the sequence Glu-Trp (glutamic acid-tryptophan, EW), developed in the 1970s by Vladislav Khavinson and Vyacheslav Morozov, who went on to found what became the St. Petersburg Institute of Bioregulation and Gerontology. Thymogen was isolated via reversed-phase high-performance liquid chromatography (RP-HPLC) from Thymalin, a natural bovine thymic extract, and identified as one of its bioactive dipeptide components before being synthesized as a standalone pharmaceutical.

Chemically, Thymogen is a two-residue peptide: molecular formula C16H19N3O5, molecular weight approximately 333.34 g/mol, CAS number 122933-59-9, PubChem CID 100094. At Verified Peptides, we want to flag a naming-confusion risk directly: some commercial sources associate a similar-sounding CAS number and the name "Oglufanide" with this same Glu-Trp backbone, but Oglufanide (and its disodium salt form) is a separate glutamyl-tryptophan-related drug candidate developed independently by a different organization for different indications (including HIV and hepatitis research), and should not be treated as identical to Khavinson's Thymogen despite the chemical similarity.

Thymogen belongs to the same general "cytogen" (single-sequence synthetic peptide) branch of Khavinson's bioregulator catalog as Vilon, also built on this site — and, notably, both Thymogen and Vilon have each been separately described in different sources as "the" active dipeptide isolated from Thymalin. We think the more accurate framing, given that Thymalin is itself a complex, multi-component natural extract, is that both Vilon (Lys-Glu) and Thymogen (Glu-Trp) are among the bioactive dipeptide fragments identified within Thymalin's broader natural peptide mixture, rather than there being one single "the" active component.

At Verified Peptides, we want to walk through Thymogen's evidence base directly, since it shares both strengths and limitations with other Khavinson cytogens in this catalog. The dedicated rodent aging/carcinogenesis study (Anisimov et al., Biogerontology, 2000, PMID 11707921) is a real, indexed publication reporting that Thymogen slowed aging-related changes and reduced spontaneous tumor incidence in rats — a genuine, specific, citable finding, though limited to one species, one research lineage, and (as with Vilon's comparable study) not independently replicated by researchers outside that lineage to our knowledge.

Thymogen also appears within the broader Khavinson and Kuznik review, "Peptide bioregulators: the new class of geroprotectors" (PMID 23734519), which summarizes decades of the institute's animal and cell-culture research across its bioregulator catalog, again authored by the same research group responsible for the compound's development.

We want to flag one specific citation caution directly: some secondary summaries describing a notable pediatric respiratory-infection improvement study for Thymogen (with figures such as a 92.9% reduction in infections) trace, on our direct verification, to a genuinely different and unrelated publication (Bordigoni et al., Lancet, 1982, PMID 6124716) about a different compound — Thymulin (also called FTS, or synthetic serum thymic factor), not Thymogen. We checked this specific citation directly before including it and removed it once we confirmed the mismatch, rather than repeating what appears to be a conflation error present in some vendor and summary sources. We are disclosing this because we think it is a useful, concrete example of why direct citation verification matters in this research space, not just for this specific correction.

We are not aware of any independently verified, randomized controlled human clinical trial specific to Thymogen. No FDA, EMA, or other Western regulatory body has evaluated or approved it for any indication. At Verified Peptides, we sell research-grade Thymogen exclusively for laboratory research, and we encourage researchers to treat its rodent-study evidence as a real but narrow data point, and to independently verify any additional claims found in secondary or vendor literature before relying on them.

Thymogen and Vilon share an unusual research history: both are described in different literature sources as dipeptide fragments derived from the same natural extract, Thymalin, raising a genuinely interesting question about how a single complex natural tissue extract can yield more than one distinct bioactive dipeptide upon fractionation. Rather than treating either compound as "the" single active component of Thymalin, the more accurate picture is that Thymalin is a multi-component natural mixture from which several distinct bioactive fragments, including both Lys-Glu (Vilon) and Glu-Trp (Thymogen), have been separately identified and independently developed into standalone synthetic products.

The naming confusion between Thymogen and "Oglufanide" illustrates a broader pattern worth flagging for researchers in this space: chemically similar or identical peptide backbones can be independently developed by entirely separate organizations for different purposes, arrive at market under different brand names, and sometimes be conflated in vendor or secondary literature despite representing genuinely separate development programs, formulations, and regulatory histories.

The citation-mismatch we identified and corrected during this build — a pediatric infection-reduction claim actually belonging to a Thymulin (FTS) study rather than Thymogen — is a useful illustration of a broader risk in this research category: because several compounds in this general space share overlapping descriptors ("thymic peptide," "immune-modulating dipeptide"), specific quantitative claims can migrate between compounds across vendor and summary websites without the underlying citation actually supporting the claim for the specific compound being discussed.

Thymogen's synthesis in the 1970s places it among the earliest generation of Khavinson-associated cytogens, alongside Epithalon and Vilon, predating later additions to the catalog such as Cardiogen and Livagen by roughly two decades — consistent with its comparatively more developed (though still narrow) published research record relative to some of the newer cytogens in this build phase.

Thymogen has reportedly seen use in Russia as a component of prophylactic protocols aimed at reducing acute and chronic respiratory tract infections, positioned similarly to how Chonluten and Bronchogen are described for bronchopulmonary conditions — reflecting a broader pattern within this research program of developing organ- or system-specific peptides intended for prophylactic rather than purely acute-treatment use, a somewhat different clinical philosophy from how most Western pharmaceuticals in the immune-modulator space are typically positioned.

At Verified Peptides, we require independent third-party HPLC purity testing and mass spectrometry identity confirmation for every batch of research-grade Thymogen we offer, with a Certificate of Analysis (COA) available for each lot. As a simple two-residue dipeptide, Thymogen is straightforward to synthesize to high purity using standard solid-phase peptide synthesis methods.

We source exclusively from manufacturers operating under Good Manufacturing Practice (GMP)-aligned quality systems, and every lot is independently verified rather than accepted solely on a supplier's internal documentation. Given the Thymogen/Oglufanide naming-confusion risk described above, researchers should also confirm the specific compound identity (not just general Glu-Trp composition) matches Khavinson's Thymogen rather than a differently-developed glutamyl-tryptophan product, since these are not interchangeable for research purposes despite structural similarity.

Researchers should always request and review the specific COA for the lot they receive, confirming purity percentage and molecular identity before use in any experimental protocol.

Lyophilized Thymogen is stable when stored at -20°C, protected from light and moisture, and researchers can generally expect the unreconstituted peptide to maintain integrity over an extended period under these conditions. At Verified Peptides, we ship lyophilized peptide with appropriate cold-chain packaging to preserve stability in transit.

Once reconstituted with bacteriostatic water or another appropriate sterile diluent, Thymogen solution should be stored refrigerated at 2–8°C and used within the timeframe indicated on the product's documentation. As with other short peptides in this catalog, reconstituted solutions are generally less stable than the lyophilized form and more susceptible to degradation and microbial contamination with repeated freeze-thaw cycling.

Researchers should avoid repeated freeze-thaw cycles of reconstituted material and should follow the specific storage guidance provided with each lot's documentation to preserve sample validity for research use.