Thymogen is the only compound in this batch that is a licensed medicine somewhere. It is the dipeptide L-Glu-L-Trp, isolated in the 1980s from Thymalin, the Khavinson group’s calf-thymus extract, and registered in Russia as an immunostimulant injection, nasal spray and cream [1]. It also has an unusual history: the same molecule was developed in the United States as IM862 (oglufanide) and tested in proper randomised trials.
My verdict: Thymogen has the most human exposure of any bioregulator in this list, and the most sobering result. When the molecule was tested independently in a placebo-controlled phase III trial, it did not work for its target indication, and the disease progressed faster [2].
The peptide bioregulators overview covers the class.
At a Glance
| Property | Detail |
|---|---|
| Sequence | L-Glu-L-Trp (EW), dipeptide; also IM862, oglufanide, alpha-glutamyl-tryptophan |
| Origin | Isolated from Thymalin (calf thymus) by Morozov and Khavinson; registered in Russia |
| Proposed mechanism | T-cell differentiation, neutrophil activation, cyclic-nucleotide signalling; anti-angiogenic effects in Western studies |
| Used for | Russia: immune deficiency with infections, post-surgical immune support. US: tested in Kaposi sarcoma and kidney cancer |
| Route | IM injection, nasal spray, cream (Russian products); research vials elsewhere |
| Typical dose range | 100 µg IM once daily for 3–10 days; nasal 25 µg per spray, 1 spray per nostril twice daily (label) |
| Evidence level | Limited: licensed in Russia on small domestic studies; the one large independent RCT (phase III, n = 202) was negative |
| Regulatory status | Approved in Russia; not FDA- or EMA-approved; not named on the WADA list |
How it works
Morozov and Khavinson report that Glu-Trp activates T-cell differentiation and recognition of peptide-MHC complexes, shifts intracellular cyclic nucleotides, and activates neutrophil chemotaxis and phagocytosis [1]. A later analysis identifies Glu-Trp and Lys-Glu (Vilon) as the active substances of Thymalin [3]. In aging rat spleen tissue, Thymogen activated B cells and increased cell renewal [4].
Chirality matters. The mirror-image form, D-Glu(D-Trp), is a separate Russian drug, Thymodepressin, used as an immunosuppressant [5]. The same two amino acids push the immune system in opposite directions depending on their 3D form, which is one more reason to care what is actually in a grey-market vial.
What the evidence shows
Human trials of the same molecule (IM862 / oglufanide)
| Study | Design | n | Dose | Result |
|---|---|---|---|---|
| Tulpule et al. 2000 [6] | Randomised comparison of two schedules, AIDS-related Kaposi sarcoma | 44 | 5 mg intranasal | 36% major responses; mild headache, fatigue, tingling, nausea |
| Noy et al. 2005 [2] | Phase III, double-blind, placebo-controlled | 202 | 5 mg intranasal every other day | Response 23% vs 21% on placebo; median time to progression 16 vs 35 weeks |
| Deplanque et al. 2004 [7] | Phase II, metastatic kidney cancer | 25 | 20 mg intranasal three times daily | No objective responses; VEGF fell; no grade 2–3 toxicity |
The phase III authors concluded that antiretroviral therapy explained most of the earlier “responses” [2], a textbook example of why uncontrolled studies mislead.
Russian clinical studies
A double-blind, placebo-controlled Russian trial gave Thymogen intranasally once daily for 7 days before abdominal cancer surgery in older patients and reported better cellular immunity and fewer post-operative complications [8]. The abstract gives the dose as “100 mg”, probably a typo for µg; I could not check the full text. Smaller studies report benefits in destructive pulmonary tuberculosis [9], and the Khavinson group’s review summarises decades of clinical use [10]. Most are small and in Russian.
Animal studies
In female rats given 5 µg SC five times a week for a year, mean lifespan did not change, but the longest-lived 10% lived longer (1,048 vs 949 days) and tumours, especially leukaemias and lymphomas, were less frequent [11].
Dosing
For informational purposes only — this summarises doses used in research and practice; it is not a prescription or individual medical advice.
| Goal | Dose | Route | Frequency / timing | Cycle length | Basis |
|---|---|---|---|---|---|
| Immune support during infection (adults) | 100 µg (1 ml of 0.01% solution) | IM injection | Once daily | 3–10 days (7 days for skin and soft-tissue infections); repeat no sooner than 1 month, up to 4 courses a year | Label (Russian product, medi.ru instructions) |
| Upper-respiratory infection, treatment | 25 µg per spray, 1 spray per nostril | Intranasal | Twice daily | 10 days; repeat no sooner than 1 month | Label (RLS entry) |
| Upper-respiratory infection, prevention | 25 µg per spray, 1 spray per nostril | Intranasal | Twice daily | 3–5 days | Label (RLS entry) |
| Pre-operative immune support in older adults | Once-daily intranasal dose (see text) | Intranasal | Once daily | 7 days before surgery | Trial [8] |
| Anti-angiogenic (oncology) | 5 mg | Intranasal | Every other day | 24 weeks | Trial [2]: not better than placebo |
| Grey-market Glu-Trp vials | No Thymogen-specific protocol found; class protocols of 1–2 mg up to 5–10 mg are applied | SC injection | Once daily | 10–20 days | Practice protocol for the class (r/peptidebioregulators, Pepdex); 10–100 times the Russian label dose |
Injection technique: peptide injection guide.
What people report: what works and what doesn’t
Reported to work
- Thymus-peptide users commonly describe fewer colds or milder seasonal allergies, though most reports concern the extract products (Thymalin, Vladonix) rather than Thymogen itself (r/Biohackers).
Mixed or unclear
- Forum users note that genuine Thymogen is sold only as a ready-made solution, never capsules, because the dipeptide is hard to dry and weigh accurately; the same thread shows users confusing Thymalin (extract) with Glu-Trp vials sold under the Thymalin name (Longecity).
Reported not to work / disappointing
- The strongest “did not work” evidence is not anecdotal: the phase III oglufanide trial [2].
A useful modern trial would test Thymogen against placebo on infection rates, vaccine responses or post-surgical recovery, and publish the full data in English.
Safety and side effects
- Mild effects in Western trials: headache, fatigue, tingling, nausea [6]; no grade 2–3 toxicity at high intranasal doses [7].
- Faster tumour progression than placebo in the Kaposi sarcoma phase III [2]. Avoid with active cancer.
- Label contraindications: hypersensitivity; the spray is not for children under one year; allergic rhinitis is listed for the spray.
- Autoimmune disease: an immunostimulant may worsen it; not studied.
- Enantiomer risk: the D-form is an immunosuppressant [5]; product identity matters.
Legal and regulatory status
- Russia: registered medicine (injection, nasal spray, cream).
- US: not FDA-approved; oglufanide never reached approval.
- EU / Germany: not authorised as a medicine by the EMA or BfArM.
- Sport: not named on the WADA 2026 list. Because it is approved in Russia, the S0 “non-approved substance” rule may not apply; athletes should check with their national anti-doping organisation.
How it fits
Thymosin Alpha-1 is the better-studied thymic peptide internationally. Vilon, the other active dipeptide of Thymalin, has more animal data but less clinical use. Background: thymic involution and immune aging.
Related Articles
- Peptide Bioregulators: The Khavinson Protocol and What the Evidence Shows
- Thymosin Alpha-1: The Immune Modulator with Real Data
- Thymic Involution and Immune Aging: Can Peptides Help?
- The Thymus
- Peptide Safety: What You Need to Know
Frequently asked questions
What is Thymogen?
Thymogen is the dipeptide L-glutamyl-L-tryptophan (Glu-Trp), isolated from the calf-thymus extract Thymalin and registered in Russia as an immunostimulant injection, nasal spray and cream.
What is the Thymogen dose?
The Russian label for the injection is 100 µg IM once daily for 3–10 days, with a repeat course no sooner than one month. The nasal spray (25 µg per dose) is one spray in each nostril twice daily for 10 days for treatment, or 3–5 days for prevention.
Is Thymogen the same as oglufanide or IM862?
Yes, the same dipeptide was developed in the US as IM862 (later named oglufanide) for its anti-angiogenic effect. A phase III trial in AIDS-related Kaposi sarcoma found it no better than placebo.
Is Thymogen the same as Thymalin?
No. Thymalin is a natural thymus polypeptide extract. Thymogen is one dipeptide isolated from it. Some grey-market vials labelled 'Thymalin' actually contain the Glu-Trp dipeptide.
Is Thymogen safe?
In the US trials of the same molecule, side effects were mild (headache, fatigue, tingling, nausea). The Russian label lists allergic reactions. In the Kaposi sarcoma phase III trial, disease progressed faster on the active drug than on placebo.
References
- Morozov VG, Khavinson VK. Natural and synthetic thymic peptides as therapeutics for immune dysfunction. Int J Immunopharmacol. 1997. https://pubmed.ncbi.nlm.nih.gov/9637345/
- Noy A, Scadden DT, Lee J, et al. Angiogenesis inhibitor IM862 is ineffective against AIDS-Kaposi’s sarcoma in a phase III trial, but demonstrates sustained, potent effect of highly active antiretroviral therapy. J Clin Oncol. 2005. https://pubmed.ncbi.nlm.nih.gov/15598977/
- Linkova N, Khavinson V, Diatlova A, et al. The Influence of KE and EW Dipeptides in the Composition of the Thymalin Drug on Gene Expression and Protein Synthesis Involved in the Pathogenesis of COVID-19. Int J Mol Sci. 2023. https://pubmed.ncbi.nlm.nih.gov/37686182/
- Chervyakova NA, Linkova NS, Chalisova NI, et al. Molecular aspects of immunoprotective activity of peptides in spleen during the ageing process (in Russian). Adv Gerontol. 2014. https://pubmed.ncbi.nlm.nih.gov/28976144/
- Deigin V, Linkova N, Vinogradova J, et al. The First Reciprocal Activities of Chiral Peptide Pharmaceuticals: Thymogen and Thymodepressin, as Examples. Int J Mol Sci. 2024. https://pubmed.ncbi.nlm.nih.gov/38732260/
- Tulpule A, Scadden DT, Espina BM, et al. Results of a randomized study of IM862 nasal solution in the treatment of AIDS-related Kaposi’s sarcoma. J Clin Oncol. 2000. https://pubmed.ncbi.nlm.nih.gov/10673512/
- Deplanque G, Madhusudan S, Jones PH, et al. Phase II trial of the antiangiogenic agent IM862 in metastatic renal cell carcinoma. Br J Cancer. 2004. https://pubmed.ncbi.nlm.nih.gov/15354209/
- Smirnov VS, Petlenko SV, El’tsin SS, et al. Application thymogen for preoperative preparation of elderly patients with tumor processes in abdominal cavity (in Russian). Adv Gerontol. 2011. https://pubmed.ncbi.nlm.nih.gov/21957588/
- Medus AI, Pisarevskaia LI, Nikishina EV, et al. The effect of thymogen on the state of immunity in destructive pulmonary tuberculosis (in Russian). Voen Med Zh. 1999. https://pubmed.ncbi.nlm.nih.gov/10605346/
- Khavinson VKh, Kuznik BI, Ryzhak GA. Peptide bioregulators: the new class of geroprotectors. Message 2. Clinical studies results (in Russian). Adv Gerontol. 2013. https://pubmed.ncbi.nlm.nih.gov/24003726/
- Anisimov VN, Khavinson VK, Morozov VG. Immunomodulatory synthetic dipeptide L-Glu-L-Trp slows down aging and inhibits spontaneous carcinogenesis in rats. Biogerontology. 2000. https://pubmed.ncbi.nlm.nih.gov/11707921/
Disclaimer: This article is for informational and educational purposes only and is not a prescription or individual medical advice. Thymogen is not approved by the FDA or the EMA.
