C tier · mixed
Thymalin is a real registered medicine in Russia — marketing authorisation ЛП-№(005867)-(РГ-RU) of 21 June 2024, holder Samson-Med, ATC L03AX, indicated for immunodeficiency states — and has 234 PubMed-indexed records behind it, which lifts it above the undefined research peptides in this family. But it is an uncharacterised bovine thymus extract, has zero registered studies on ClinicalTrials.gov, and its headline geroprotective claim of a 2.0- to 4.1-fold mortality reduction rests on one 266-subject study from the originating group that nobody has replicated in more than twenty years.
thymalin
Thymalin is a water-soluble polypeptide fraction extracted from the thymus glands of calves, developed in Leningrad in the late 1970s by Vladimir Khavinson and Vyacheslav Morozov and registered in Russia as an injectable immunostimulant for immunodeficiency states. It is important to be clear that it is not a defined short peptide: the label declares a thymus extract, and the originating group itself describes Thymalin as ‘a polypeptide extract of thymus’ whose activity it attributes to two contained dipeptides, KE (Vilon) and EW (Thymogen). Beyond the Russian registration, the evidence is a large but almost entirely single-ecosystem literature in Russian-language and Russian-translated journals, with no marketing authorisation, regulatory assessment or replication attempt anywhere in the West.
// we supply this one
available as a research reagent
polypeptide fraction — lot-specific COA · lyophilised powder · batch certificate published. Grade C above is our own and is not adjusted because we stock it.
the explanation
Thymalin is not a single peptide — it is a mixture of protein fragments squeezed out of calf thymus glands. Unlike most things in this family, it is a genuinely licensed medicine in Russia, where it is approved as an injection to help people with weakened immune systems. The eye-catching claim, that it cut death rates in elderly people two- to four-fold, comes from one study by the people who invented it, and no laboratory outside their circle has ever tried to repeat it.
regulatory status
Registered medicine in Russia; unapproved and research-only in the UK
Thymalin holds a current Russian marketing authorisation, ЛП-№(005867)-(РГ-RU) dated 21 June 2024, held by Samson-Med LLC, as a lyophilisate for intramuscular injection classified under ATC L03AX (other immunostimulants); its approved indications are immunodeficiency states in adults and in children from six months, including purulent and septic infection, thymus insufficiency after irradiation or thymectomy, impaired regeneration, and marrow and immune suppression after chemotherapy or radiotherapy. It has no marketing authorisation in the UK, EU or US, no MHRA, EMA or FDA assessment, and a ClinicalTrials.gov search across Thymalin and its sibling bioregulators returns no registered study. It is not a controlled drug under the Misuse of Drugs Act and is not an authorised food-supplement or novel-food ingredient in Great Britain, so it is lawfully supplied here only as a laboratory research reagent. Thymalin is not named on the WADA Prohibited List, although WADA's broadly drafted S0 (unapproved substances) and S2 (peptide hormones and growth factors) classes are written to capture unapproved biologically active preparations.
how it works · proposed mechanism
Thymalin is presented as a thymomimetic — a substitute for the declining hormonal output of the involuting thymus — rather than as a receptor ligand. Because it is an extract, its mechanism is a mechanism of a mixture, and the originating group has progressively reinterpreted it as the sum of contained ultrashort peptides. That reinterpretation is a hypothesis about which molecules in the mixture matter, not an independently established fact.
Thymomimetic immune reconstitution
The core claim is restoration of T-lymphocyte differentiation and normalisation of helper/suppressor ratios in states of thymic insufficiency, which is the basis of the Russian registered indication. This is classical thymic-extract pharmacology shared with thymostimulin, thymopentin and other 1980s thymic preparations, most of which failed to survive modern regulatory scrutiny elsewhere.
Attribution to two contained dipeptides
A 2023 paper from the group states plainly that ‘KE and EW dipeptides are active substances of Thymalin’ and models them docking into promoter regions of immune and coagulation genes, with supporting work in lipopolysaccharide-stimulated human mononuclear cells. This makes Thymalin, Vilon and Thymogen a single evidence complex rather than three independent compounds, and it means the registered extract's activity is being explained by molecules that are themselves unapproved.
Cytokine and coagulation modulation
In the group's 2020 COVID-19 study, adding Thymalin to standard care was reported to lower interleukin-6 5.5-fold versus 1.41-fold in controls, lower C-reactive protein 9.7-fold versus 1.7-fold, lower D-dimer 5.7-fold versus 2.1-fold, and raise CD4 counts by 88.9 percent. These are large biomarker effects in an open-label design with 42 treated and 50 control patients and no deaths in either arm, so no clinical outcome separated the groups.
Claimed geroprotection
The 2003 Thymalin/Epithalamin work reports that two to three years of treatment in 266 elderly subjects, followed for six to eight years, reduced mortality 2.0-fold for Thymalin alone in St Petersburg and 2.1-fold in Kiev, and 4.1-fold for six years of combined therapy. A mortality effect of that size from a short course of a thymus extract is an extraordinary claim, and it has never been tested by anyone outside this group.
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
Thymalin's registration is real but it is a Soviet-era immunostimulant dossier in one jurisdiction, not evidence that the marketed anti-ageing claims are true. The two claims doing the commercial work — a 2.0- to 4.1-fold mortality reduction in the elderly and a dramatic anti-cytokine effect in severe COVID-19 — come from the same St Petersburg group, in Neuroendocrinology Letters and a single open-label 92-patient trial respectively, with zero registered trials and zero replication attempts outside Russia in over two decades. Because Thymalin is an undefined calf thymus extract rather than a molecule, there is no sequence, formula, molar mass or CAS number to verify, and batch-to-batch identity cannot be assumed. Its own originators now attribute its activity to the dipeptides Lys-Glu and Glu-Trp, which means the Thymalin, Vilon and Thymogen entries in this index describe one shared body of evidence, not three. Anything sold in the West as ‘Thymalin’ is also not the Russian licensed product and carries no assurance of matching it.
key published findings
- Russian registration verified: marketing authorisation ЛП-№(005867)-(РГ-RU) of 21 June 2024, holder Samson-Med LLC, lyophilisate for intramuscular injection, ATC L03AX, indicated for immunodeficiency states including post-chemotherapy and post-irradiation immune suppression.
- ClinicalTrials.gov holds no registered study of Thymalin; an intervention-field query returns zero and a broad term query across the whole bioregulator family returns only one unrelated breast-cancer pathology study.
- The 2003 geroprotection paper describes 266 elderly subjects at centres in St Petersburg and Kiev with 6–8 year follow-up and reports mortality reductions of 2.0-fold (Thymalin, St Petersburg), 2.1-fold (Thymalin, Kiev) and 4.1-fold for six years of combined Thymalin plus Epithalamin.
- The 2020 COVID-19 study is described by its authors as single-centre, open-label, prospective, randomised and controlled, with 42 treated and 50 control patients; it reported large biomarker shifts but zero deaths in either arm, so it demonstrated no mortality or clinical-outcome benefit.
- The originating group states in a 2023 International Journal of Molecular Sciences paper that Thymalin is ‘an immunomodulatory drug containing a polypeptide extract of thymus’ and that ‘KE and EW dipeptides are active substances of Thymalin’ — an explicit link to Vilon and Thymogen.
- Thymalin has no verifiable chemistry: as an extract it has no sequence, molecular formula, molar mass or CAS number, and all four fields are recorded as null here rather than guessed.
limitations of the evidence
- Thymalin is a biological extract, not a defined short peptide, so no chemical identity, purity specification or structure-activity reasoning can be applied to it — the frequent presentation of it alongside defined bioregulator peptides is itself misleading.
- The registration is confined to Russia and rests on a legacy immunodeficiency dossier; there is no MHRA, EMA or FDA assessment, no published regulatory review of the underlying data, and no registered trial anywhere.
- Thymalin, Vilon and Thymogen share one body of evidence by the originating group's own account, since it names KE and EW as Thymalin's active substances; claims made for any one of the three should not be read as independent support for the others.
- The 2003 mortality study is the same study cited in support of Epithalamin and, by extension, epitalon; it is a single report in a low-impact journal with no published protocol, no registration and no independent audit of the survival data.
- Essentially the entire literature is authored by the St Petersburg Institute of Bioregulation and Gerontology and its long-standing collaborators, and is published in Advances in Gerontology, Bulletin of Experimental Biology and Medicine and similar Russian-language or Russian-translated venues.
- Material sold in the West under the name Thymalin is a research reagent of unverified provenance and is not the Russian licensed medicine; equivalence between the two has never been demonstrated.
documented safety signals
- Thymalin is a bovine tissue-derived injectable, so it carries the generic concerns of animal-origin biologicals — immunogenicity and, in principle, transmissible spongiform encephalopathy risk — which is precisely the reason regulators in the EU and US withdrew or never accepted comparable thymic extracts.
- No serious adverse events are reported in the published Russian literature, but that literature is not accompanied by any regulator-audited pharmacovigilance dataset accessible outside Russia.
- Immunostimulation is not risk-free in principle: agents that expand T-cell activity have theoretical potential to aggravate autoimmune disease, and no adequately powered safety study addresses this for Thymalin.
- Research-grade material sold outside Russia has no audited manufacturing standard, so impurity, endotoxin and species-of-origin risk are entirely unquantified.
identity
| full name | Thymalin (polypeptide extract of calf thymus) |
| category | Other |
| modality | other |
laboratory handling
| storage | Supplied as a lyophilisate and stored desiccated at 2-8 °C, protected from light. This is a polypeptide preparation rather than a single defined peptide, so batch-to-batch composition varies and the certificate of analysis describes the lot rather than a molecule. Handling information only. |
| solubility | Soluble in sterile water and aqueous buffer; solutions are prepared fresh. |
| co-studied with | Combining Thymalin with Vilon or Thymogen adds no independent evidence, because the originating group identifies Lys-Glu and Glu-Trp as Thymalin's own active constituents; the 4.1-fold mortality figure often quoted for ‘combined therapy’ refers specifically to Thymalin plus Epithalamin in the 2003 study and has never been reproduced. |
Handling information describes laboratory practice for a research reagent. It is not a preparation guide for use in humans.
the receipts
7 citedVidal Russia medicines reference · 2024 · official
ClinicalTrials.gov, US National Library of Medicine · 2026 · official
PubMed, US National Library of Medicine · 2026 · official
Advances in Gerontology / Uspekhi Gerontologii · 2013 · review
Neuroendocrinology Letters (author-hosted scan of the published paper) · 2003 · randomized
Stem Cell Reviews and Reports · 2020 · randomized
International Journal of Molecular Sciences · 2023 · preclinical
others in Other