Educational content only. Not medical advice, and no doctor-patient relationship is created. Read the medical disclaimer
Peptide
Thymogen
Also known as: Oglufanide (Glu-Trp, IM862)
A two-amino-acid peptide originally derived from thymus extract, used in Russia as an immune modulator. Larger U.S. trials, under the name IM862, did not show benefit over placebo.
Tier 3 · Education only
Grade C · Limited human evidence
Educational content only, not medical advice. Discussion here does not mean this therapy is prescribed by Youthful Medicine or available to you. Read the medical disclaimer
U.S. regulatory status
Not FDA-approved in the U.S. Registered as an immunomodulator in Russia. Not on the 503A bulks list and not among the peptides reviewed for U.S. compounding.
Not FDA-approved. Oglufanide reached Phase III in the U.S. only as an investigational drug (IM862, Cytran) and was not approved. It is not on the 503A bulks list and was not among the peptides the FDA Pharmacy Compounding Advisory Committee reviewed in 2024 to 2026, so it is not eligible for routine 503A compounding.
What it is
Thymogen is the dipeptide L-glutamyl-L-tryptophan (Glu-Trp, also called the EW dipeptide). It was identified in Thymalin, a calf thymus peptide extract, then synthesized at the St. Petersburg Institute of Bioregulation and Gerontology under Vladimir Khavinson and patented in 1990. In Russia it is registered as Thymogen in a nasal spray and an injectable solution. In the U.S. it was studied as oglufanide (IM862). It is a different molecule from thymosin alpha-1 (thymalfasin, a 28-amino-acid peptide), although both are called thymic immunomodulators.
How it is thought to work
Russian studies describe it as thymomimetic: it is reported to support T-cell differentiation and to normalize CD3, CD4 and CD8 counts and the CD4/CD8 ratio, and to support innate defenses such as neutrophil phagocytosis. Lab work shows shifts in the cyclic messengers cAMP and cGMP and, in human macrophages, lower TNF and IL-6 after a bacterial trigger. Russian authors also propose that short peptides like Glu-Trp influence gene expression of immune proteins. Most of these effects come from small or laboratory studies and are not established in people.
The science, in depth
Thymogen belongs to the family of short regulatory peptides developed by Khavinson and colleagues. In rat studies the dipeptide activated T-cell differentiation, neutrophil chemotaxis and phagocytosis, and changed intracellular cAMP and cGMP. A 2022 study in human THP-1 macrophages found that Khavinson peptides, including Thymogen, reduced LPS-induced TNF and IL-6 and cell adhesion. Glu-Trp also showed anti-angiogenic activity in endothelial and animal models, which led to its cancer trials. Thymogen vs thymosin alpha-1: much of what is written about Thymogen online borrows evidence from thymosin alpha-1, a different thymic peptide. Thymosin alpha-1 has its own data, including dendritic-cell signaling through TLR9, regulatory T-cell induction, the ETASS sepsis trial (28-day mortality 26.0% vs 35.0%, not statistically significant on the primary analysis) and the larger TESTS trial (BMJ 2025, 1,106 adults, 23.4% vs 24.1%, no overall benefit). A Cochrane review of thymic peptides in cancer found fewer severe infections with purified thymus extracts. These findings belong to other molecules and should not be applied to Thymogen.
Animations simplify biology for teaching. They are not a claim that this peptide works this way in people.
What the research shows
In Russia, Thymogen has been used for decades for secondary immunodeficiency and recurrent infections (chronic bronchitis, sinusitis, skin infections, respiratory viral infections), as an add-on in chronic viral infections, to reduce infections after surgery, to support immune recovery during cancer treatment, in COVID-19 protocols, and in older adults. These studies are mostly open-label, small (often 30 to 200 patients), published in Russian and frequently not indexed in PubMed, so their reported benefits cannot be confirmed. One double-blind placebo-controlled trial in older adults before abdominal cancer surgery (2011) reported better cellular immunity and fewer postoperative complications. In contrast, the U.S. randomized trials were negative: in AIDS-related Kaposi sarcoma (202 patients, 2005) response was 23% vs 21% on placebo, with shorter time to progression on IM862; in prostate cancer (71 patients, 2007) it did not delay PSA progression; and a renal cancer study produced no responses.
Clinical trials to watch
No active trials of Thymogen are registered in the U.S. Related and worth watching: a recruiting Phase 1 trial of thymalfasin (thymosin alpha-1) as a vaccine-response enhancer in older adults receiving COVID-19 boosters (NCT06821100, 75 participants). For Thymogen itself, what is needed are modern randomized trials in infection prevention or immune aging.
Safety and considerations
Generally well tolerated in published trials; reported effects were mild headache, fatigue, tingling and nausea, and Russian post-marketing reports describe rare allergic reactions. There are no controlled data in pregnancy or breastfeeding. Caution is advised during an active autoimmune flare, after organ transplantation, and with immunosuppressive medicines, which need physician supervision. It is not a substitute for antibiotics, antivirals or standard infection care. U.S. research-peptide products are unregulated, so sterility and content are not assured, and there are no long-term randomized trials of Thymogen itself.
Testing and monitoring
Thymogen is not approved in the U.S., so there is no standard U.S. monitoring protocol. These are the general immune and safety checks a physician might consider when discussing any immune-modulating peptide. Education only, not a treatment plan.
Before starting
Complete blood count with differential, including lymphocyte count
Comprehensive metabolic panel (liver and kidney function)
Review of autoimmune history, current immunosuppressive medicines and vaccines
Optional immune profiling, such as lymphocyte subsets (CD4, CD8), where clinically relevant
During care
Repeat blood count and metabolic panel at intervals the physician chooses
Track infections, symptoms and any change in autoimmune activity
Check product source and quality, since unregulated research peptides vary
Needs a physician’s attention
Allergic reactions, rash or swelling
New or worsening autoimmune symptoms
Fever or infection that does not settle
Any planned use alongside cancer treatment or immunosuppressants
Sources: general immunology monitoring practice; safety reports from IM862 trials (J Clin Oncol 2000, 2005).
Educational only, not medical advice. These are the tests researchers and clinicians discuss, not a personal plan. A licensed physician should decide what to order, interpret your results, and manage any therapy. Do not start, stop, or change a treatment based on this page.
What this research could teach us
Thymogen is a clear example of why evidence quality matters: decades of positive small studies, followed by negative placebo-controlled trials once rigorous designs were used. It also raises a useful question for immune aging: whether a subset of people with measurable T-cell deficits might respond, which only biomarker-guided trials could answer.
Our position
An interesting immune-modulation story with a long Russian clinical history, but the best-controlled U.S. trials were negative. We rate it limited human evidence and education only, and we will update this page if new randomized data appear.
Video lesson
Sources and further reading
Thymogen / Glu-Trp: Tulpule A, et al. J Clin Oncol 2000;18(4):716-23 (doi:10.1200/JCO.2000.18.4.716). Phase III IM862 in AIDS-Kaposi sarcoma, J Clin Oncol 2005 (doi:10.1200/JCO.2005.11.043). Phase II IM862 in renal cell carcinoma, Br J Cancer 2004 (doi:10.1038/sj.bjc.6602126). Mao S, et al. Prostate 2007;67(15):1677-85 (doi:10.1002/pros.20649). Anisimov VN, et al. Biogerontology 2000;1(1):55-9 (doi:10.1023/a:1010042008969). Khavinson peptides in THP-1 macrophages, Int J Mol Sci 2022 (doi:10.3390/ijms23073607). Khedr S, et al. Acta Physiol 2020;231(2):e13556 (doi:10.1111/apha.13556). Elderly surgical patients RCT, Adv Gerontol 2011 (PMID 21957588). Related thymic peptides, cited for comparison only: Romani L, et al. Blood 2004 (doi:10.1182/blood-2003-11-4036). Romani L, et al. Blood 2006 (doi:10.1182/blood-2006-02-004762). Wu J, et al. ETASS, Crit Care 2013 (doi:10.1186/cc11932). Wu J, et al. TESTS, BMJ 2025 (doi:10.1136/bmj-2024-082583). Wolf E, et al. Thymic peptides for cancer patients, Cochrane 2011 (doi:10.1002/14651858.CD003993.pub3). ClinicalTrials.gov NCT06821100.
AT A GLANCE
Quadrant
Autoimmunity & Inflammation
Tier
Tier 3 · Education only
Evidence grade
Grade C · Limited human evidence
Last reviewed
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