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Evidence: LowPeptideNot FDA ApprovedSynthetic dipeptide (Glu-Trp) immunomodulatorUsed in Russia · not FDA/EMA-approvedImmune support (Russian trials)

Thymogen

A two-amino-acid peptide from Soviet thymus research, used in Russia as an immunomodulator, backed by small Russian-language trials

Thymogen is L-glutamyl-L-tryptophan, a synthetic dipeptide developed in the Soviet Union and used there and in Russia as an immunomodulating drug, given by injection or into the nose. Its clinical literature is Russian, mostly from the 1990s, and mostly small or uncontrolled: studies in pelvic infections, tuberculosis, type 1 diabetes and respiratory infections in soldiers report normalised lymphocyte counts and clinical improvement. One double-blind trial in elderly surgical patients reported fewer postoperative complications. It has no FDA or EMA approval.

At a Glance Read Research →
Overview

What is it?

Thymogen is two amino acids, glutamic acid and tryptophan, joined as L-Glu-L-Trp. It was developed in the Soviet Union from thymus research and used as an immunomodulator. A 2024 review pairs it with thymodepressin, made from the mirror-image D-amino acids, which suppresses immune responses instead.

Its human evidence is mostly Russian-language studies: in pelvic infections, type 1 diabetes, tuberculosis and respiratory infections among soldiers, authors reported normalised immune measures and clinical improvement. Most had no control group, and their abstracts report proportions without statistics.

The strongest design is a double-blind, randomised, placebo-controlled trial in elderly patients preparing for abdominal tumour surgery: a week of intranasal thymogen before surgery restored measures of cellular immunity and was followed by fewer postoperative complications and shorter recovery. In rats, monthly courses reduced tumours caused by radioactive strontium and caesium. Thymogen has no FDA or EMA approval, and its trials have not been repeated outside Russia.

Structured data

At a Glance

Every value in this table is printed from the Grey Peptides dataset, the same record the compound explorer and comparison tool read, so the three can never disagree.

ClassA synthetic dipeptide (Glu-Trp) isolated from thymic bioregulator preparations and registered in Russia as a medicine; positioned in the Khavinson framework as the characterized active fragment of Thymalin.
SequenceGlu-Trp
FormulaC16H19N3O5
Molecular weight333.34 g/mol
Half-lifeNot reported in the abstracts read
Typical dosecourses of daily doses (Russian studies), injection or intranasal
US statusNot FDA Approved
Approved elsewhereRussia
Evidence levelLow
Last reviewed2026-09-30
Evidence

Published Research

These are the studies of thymogen that carry abstracts, read from PubMed. Most are Russian-language clinical reports from the 1990s with English abstracts.

Human2011

Double-blind trial before tumour surgery in older patients

In a randomised, placebo-controlled study, elderly patients received intranasal thymogen once daily for 7 days before surgery for abdominal or retroperitoneal tumours. It restored structural and functional measures of cellular immunity and was followed by fewer and less extensive postoperative complications and a shorter postoperative period.

PMID: 21957588
Human1992

Pelvic infections in 46 women

Added to treatment of acute pelvic infections in 46 women, thymogen normalised lymphocyte and T- and B-cell counts; the authors reported a marked clinical effect and no complications.

PMID: 1476231
Human1996

Type 1 diabetes with secondary immunodeficiency

Thymogen was reported to remove signs of secondary immunodeficiency by activating T-lymphocyte differentiation, with a clinical effect in 94.4% and a laboratory effect in 83.3% of patients.

PMID: 9026934
Human1999

Destructive pulmonary tuberculosis

Thymogen was reported to stimulate T-cell immunity, improve tolerance of anti-tuberculosis drugs, heal cavities and stop bacterial shedding.

PMID: 10605346
Human1993

Respiratory infections in a military training unit

Intranasal and subcutaneous thymogen used as prophylaxis was reported to reduce the frequency, severity and duration of influenza and other acute respiratory infections.

PMID: 8498021
Animal1992

Radiation-induced tumours in rats

Female rats drinking water with strontium-90 and caesium-137 for 12 months developed more tumours, especially breast adenocarcinoma; monthly five-day courses of thymogen reduced total tumour and cancer occurrence.

PMID: 1300740
Review2024

Thymogen and its mirror image

The review presents thymogen (L-Glu-L-Trp), an immunostimulant, and thymodepressin (D-Glu(D-Trp)), an immunosuppressor, as the first examples of up-and-down immune regulation by two enantiomeric drugs.

PMID: 38732260
Safety

Side Effects & Contraindications

Reported Side Effects

From the studies above, which reported little on safety.

● No complications reported in the pelvic-infection study
● Safety data otherwise sparse in the published abstracts

Contraindications & Cautions

No product label was read for this page. These cautions follow from the evidence.

● Products sold outside Russia's regulated supply — identity and dose are unverified
● Small, mostly uncontrolled trials — benefits are uncertain
● Tested athletes — see the Sport (WADA) row below
Questions

Frequently Asked Questions

?What is thymogen?

A synthetic dipeptide, L-glutamyl-L-tryptophan, developed in the Soviet Union and used in Russia as an immunomodulator, by injection or into the nose.

?Does thymogen work?

Russian studies from the 1990s report improved immune measures and clinical results, but most had no control group. One double-blind trial in older surgical patients reported fewer complications; none has been repeated outside Russia.

?Is thymogen approved in the US or EU?

No. FDA's Drugs@FDA database and EMA's register have no entry for it.

Bibliography

References

  1. [pubmed] Smirnov VS, et al. "[Application thymogen for preoperative preparation of elderly patients with tumor processes in abdominal cavity]." Adv Gerontol, 2011;24(2):278-84. PMID: 21957588.
  2. [pubmed] Tsvelev IuV, et al. "[Thymogen in the complex treatment of inflammatory diseases of the female genital system]." Akush Ginekol (Mosk), 1992:54-7. PMID: 1476231.
  3. [pubmed] Zhuk EA, et al. "[Thymogen in the treatment of type-1 diabetes mellitus]." Ter Arkh, 1996;68(10):12-4. PMID: 9026934.
  4. [pubmed] Medus AI, et al. "[The effect of thymogen on the state of immunity in destructive pulmonary tuberculosis]." Voen Med Zh, 1999;320(10):65-7, 96. PMID: 10605346.
  5. [pubmed] Furgal SM, et al. "[The clinico-epidemiological efficacy of thymogen in acute respiratory viral infections in a military collective]." Voen Med Zh, 1993:31-2, 80. PMID: 8498021.
  6. [pubmed] Anisimov VN, et al. "[The effect of the synthetic immunomodulator thymogen on radiation-induced carcinogenesis in rats]." Vopr Onkol, 1992;38(4):451-8. PMID: 1300740.
  7. [pubmed] Deigin V, et al. "The First Reciprocal Activities of Chiral Peptide Pharmaceuticals: Thymogen and Thymodepressin, as Examples." Int J Mol Sci, 2024;25(9). PMID: 38732260.
  8. [fda] FDA. Drugs@FDA (openFDA): no application for thymogen. Read September 30, 2026.
  9. [other] European Medicines Agency. Medicines register: no entry for thymogen. Read September 30, 2026.

Sources & Citations

Every study on this page was read from its PubMed record; most are Russian-language papers with English abstracts. Regulatory status comes from FDA's Drugs@FDA database and EMA's register, read September 30, 2026. Grey Peptides sells nothing and links to no vendor.

Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Consult a licensed healthcare provider before making health decisions.

Last reviewed: 2026-09-30