PwPepwise

Thymogen

Antioxidants

Khavinson dipeptide (Glu-Trp)

Thymogen is a small synthetic dipeptide (glutamyl-tryptophan, or Glu-Trp) derived from thymic tissue research, designed to support.

§Dosing at a glance

3 protocols · from the research
What it's forDoseHow oftenHowFor how long
into the nose (Human — Preoperative Immunomodulation)100 mg/dayOnce dailyIntranasalSprayed into the nose.7 days
Intraperitoneal (Animal — Hepatoprotection)10 μg/kg—IntraperitonealInjected into the abdominal cavity (research use).—
under the skin/Systemic (Animal — Carcinogenesis Inhibition)5 μg———

Approximate values pulled from the research — double-check before dosing.

§01Summary

Thymogen is a small synthetic dipeptide (glutamyl-tryptophan, or Glu-Trp) derived from thymic tissue research, designed to support and restore immune system function. It belongs to a class of thymic peptide immunomodulators developed primarily in Russia and the former Soviet Union. By influencing T-lymphocyte activity and broader immune cell function, Thymogen appears to help the body recover more effectively from immune suppression caused by surgery, infection, toxic exposure, or radiation1,12,13.

Clinical and preclinical research suggests Thymogen may support recovery in patients undergoing major surgery by restoring cellular immunity parameters and reducing postoperative complications1. It has been reported to enhance neutrophil and phagocytic cell activity14, and preliminary evidence suggests it may offer hepatoprotective benefits through immune-mediated pathways2,7,15. In animal models, it has been reported to reduce viral lung damage in influenza3, support hematopoietic recovery following radiation exposure13,19, and inhibit radiation-induced carcinogenesis11. Administered intranasally, it offers a practical, non-invasive delivery route with demonstrated immunomodulatory activity1,3. Human studies are actively emerging across a range of indications, with early findings pointing to a favorable tolerability profile.

This is the layperson summary. Mechanism, dosing, the evidence base, and the published literature are in the sections below — every claim links to its source.

§02In depth

Thymogen is a synthetic dipeptide consisting of L-glutamic acid and L-tryptophan (Glu-Trp), structurally derived from bovine thymic extracts through isolation and characterization of active immunoregulatory fractions. Its minimal dipeptide structure distinguishes it from larger thymic polypeptides such as thymosin or thymulin, and its small molecular size confers relative metabolic accessibility and flexibility in administration routes, including intranasal delivery1,3.

The primary mechanism of action appears to center on modulation of T-lymphocyte differentiation and activation. Thymogen has been reported to increase total T-lymphocyte counts and T-helper (CD4+) cell populations in immunosuppressed human subjects6,18, consistent with a thymopoietic or thymo-mimetic function that partially recapitulates signals normally provided by intact thymic tissue. The hepatoprotective activity of Thymogen is notably thymus-dependent — studies in thymectomized rats demonstrate complete abolition of hepatoprotective efficacy following thymic removal, even though immunomodulatory effects on antibody-forming cells in the spleen are preserved15. This dissociation suggests that hepatoprotection is mediated through a distinct, T-cell-dependent immune effector pathway rather than through direct cytoprotection.

At the innate immune level, Thymogen stimulates neutrophil ingestive (phagocytic) activity and enhances reactive oxygen species generation, increasing DCF-DA luminescence by approximately 80% in neutrophils and stimulating hydrogen peroxide synthesis in monocytes at 10 mM concentrations in vitro14. It also appears to restore natural killer cell function and macrophage-mediated humoral immune responses in toxic immunodeficiency states induced by acetonitrile poisoning12, and to reverse immune suppression in secondary candidiasis models by reactivating thymus-dependent immunocompetent cells20.

Thymogen's antioxidant and hepatoprotective pharmacology in animal models involves inhibition of lipid peroxidation (reduction of malondialdehyde levels) and restoration of catalase activity in liver tissue and blood plasma2,7. Notably, these effects display a non-linear dose-response relationship: lower doses (10 μg/kg intraperitoneally) appear at least as effective as ten-fold higher doses (100 μg/kg), consistent with a bell-shaped or plateau pharmacodynamic curve sometimes seen with peptide immunomodulators2. D-alanine-modified analogues of Thymogen, particularly with C-terminal D-Ala substitution, demonstrate enhanced hepatoprotective and antioxidant activity compared to native Thymogen, likely through improved resistance to enzymatic degradation and extended biological half-life2,7.

Radioprotective properties have been attributed to Thymogen's capacity to stimulate hematopoietic progenitor cell (CFU-S) recovery following ionizing radiation exposure13,19, and to modulate radiation-induced immunodepressive, hematopoietic, and gastrointestinal injury syndromes19. In vitro genoprotective activity — reduction of formaldehyde-induced chromosomal aberrations — has been demonstrated at low concentrations in human lymphocyte cultures, though the molecular mechanism of this DNA-protective effect remains an active area of investigation16.

§04Evidence & efficacy

Evidence base
122Studies
31Human
27Animal

Thymogen's most robustly supported efficacy signal comes from a placebo-controlled RCT demonstrating that preoperative intranasal administration in elderly patients undergoing abdominal tumor surgery may restore cellular immunity parameters and reduce both the rate of postoperative complications and the duration of postoperative recovery1. Beyond this single controlled human trial, the efficacy evidence base is largely composed of uncontrolled human observational studies and animal model data.

In human observational studies, Thymogen has been reported to normalize T-lymphocyte counts, T-helper ratios, and non-specific immune reactivity markers in patients with chronic suppurative obstructive bronchitis18 and chronic staphylococcal pyoderma6, and to accelerate correction of immune deficiency and coagulopathy in post-Caesarean endometritis when added to standard therapy8. Thymogen has been reported to stimulate neutrophil phagocytic activity and reactive oxygen species production in vitro using donor peripheral blood14.

In animal models, Thymogen appears to reduce viral lung damage in lethal H1N1 influenza, with viral load reductions of approximately 32-fold on day 3 post-infection compared to untreated controls under prophylactic administration3. Hepatoprotective activity has been demonstrated in hydrazine-induced rat hepatopathy models, with lower doses (10 μg/kg) appearing sufficient to inhibit lipid peroxidation and restore catalase activity2,7,15. The mechanism of hepatoprotection appears to be thymus-dependent, as it was abolished following thymectomy in animal experiments15. Thymogen has been reported to inhibit both spontaneous and radiation-induced carcinogenesis in female rats, with treated animals also exhibiting extended lifespan11. Radioprotective properties on hematopoietic stem cells (CFU-S) have been reported, with approximately 50% reduction in radiation-induced CFU-S damage at 1 Gy13,19. Additional reported effects include cytoprotection of striated muscle under cold stress4, acceleration of corneal epithelial repair after thermal burn5, restoration of immune function following toxic chemical exposure12, and anti-stress behavioral and cortisol-normalizing effects in combination therapy9.

Genoprotective activity — specifically, reduction of formaldehyde-induced chromosomal aberrations at low concentrations — has been observed in human lymphocyte cultures16.

§05Safety

Thymogen has demonstrated acceptable tolerability across the available human and animal studies, with no serious adverse events explicitly reported in any of the reviewed literature. In the highest-quality human study — a placebo-controlled RCT in elderly oncological surgery patients — intranasal Thymogen at 100 mg/day for 7 days was well tolerated with no reported adverse events1. In animal models spanning hepatopathy, radiation injury, cold stress, corneal burn, and carcinogenesis, Thymogen-treated animals showed no reported toxicity signals and in some cases demonstrated improved survival compared to controls2,4,11.

At high in vitro concentrations (10–1000 μg/ml), Thymogen has been observed to reduce lymphocyte proliferative and mitotic activity in human peripheral blood lymphocyte cultures, indicating a concentration-dependent cytotoxicity threshold that is unlikely to be reached under standard clinical dosing16. At low concentrations (0.001–1.0 μg/ml), no mutagenic activity was detected, and a genoprotective effect against formaldehyde-induced chromosome aberrations was observed16. In intact animals, stimulation of corneal epithelial DNA synthesis was noted with Thymogen administration, a finding that warrants characterization with longer-term study designs5.

No drug interactions, contraindications, or immunologically mediated adverse reactions were reported across the reviewed studies. Long-term human safety data and formal pharmacovigilance datasets are areas where the evidence base is actively developing.

§06History

Thymogen (Glu-Trp) was developed in the Soviet Union, primarily through the collaborative work of researchers including V.Kh. Khavinson, V.G. Morozov, and colleagues at institutions associated with the Soviet military-medical and gerontological research establishment. Its origins lie in the systematic fractionation of bovine thymic extracts conducted from the 1970s onward, aimed at isolating the minimal active immunoregulatory units responsible for thymic peptide bioactivity. Thymogen represents one of the smallest biologically active thymic fractions identified through this program, alongside related preparations such as thymalin and thymohexin10,11.

Early experimental work in the late 1980s and early 1990s established foundational immunomodulatory properties, including effects on T-lymphocyte populations6, corneal wound healing5, resistance to candidal infection under immunosuppression20, and radioprotection of hematopoietic stem cells13. A pivotal 1992 study reported that Thymogen inhibited both spontaneous and radiation-induced carcinogenesis in female rats, with treated animals also demonstrating extended lifespan — findings that positioned it as a potential anti-aging and chemopreventive agent11.

Throughout the 1990s and 2000s, Russian-language clinical research explored Thymogen across a broad range of immune-deficiency states, infectious conditions, and surgical contexts1,18. The peptide was developed into a registered pharmaceutical product in Russia, available as an intranasal spray formulation (Thymogen®)3. Contemporary research, extending into the 2020s, has focused on D-amino acid-modified analogues with enhanced metabolic stability2,7 and antiviral applications including influenza prophylaxis3, reflecting ongoing refinement of the original dipeptide scaffold.

§07References