Thymalin
Thymalin; polypeptide extract of calf thymus (containing active dipeptides EW [Glu-Trp, 'thymogen'] and KE [Lys-Glu], and tripeptide EDP [Glu-Asp-Pro, 'crystagen'])
Thymalin is a polypeptide extract from calf thymus containing short bioactive peptides (EW, KE, EDP) that modulate immune function via epigenetic/gene-regulatory mechanisms, promoting T-cell differentiation and anti-inflammatory cytokine regulation. No classical receptor binding affinities have been established. Small controlled studies in COVID-19 elderly patients showed faster immune recovery vs standard therapy (PMC8654498, PMC8365293).
Last updated: 2026-03-13
Safety Summary
Clinical trial literature and medical summaries describe thymalin as well tolerated with 'practically no side effects.' No consistent acute adverse events, published event-frequency tables, dose-limiting toxicities (DLTs), or maximum tolerated dose (MTD) have been reported in publicly available clinical literature (PMC8365293, PMC8654498, Pillintrip thymalin listing). Pharmacovigilance searches of FAERS, EudraVigilance, and WHO VigiBase returned no specific safety signals attributable to thymalin. No CYP enzyme interactions documented. No anti-drug antibody formation reported. Systematic reviews of thymic peptides (Cochrane/Wolf et al. 2011, PMC6481824) report generally favorable profiles. No tolerance, tachyphylaxis, or withdrawal effects reported. CRITICAL DATA GAPS: No formal preclinical chronic/subchronic toxicology studies with NOAEL/LOAEL, no carcinogenicity/genotoxicity reports, no reproductive/developmental toxicity studies, and no dedicated PK studies in renal or hepatic impairment are publicly available. The 'clean' safety profile should be interpreted with caution as it likely reflects absence of rigorous safety monitoring rather than proven safety. Trials were small, unblinded, and may have underreported events. Community reports on Longecity and online communities generally report minimal side effects.
Known Side Effects
uncommon
rare
Who Should NOT Use This
Contraindicated per product labeling. Risk of allergic reaction to bovine-derived protein extract (Pillintrip thymalin product information).
Contraindicated per product labeling. No reproductive or developmental toxicity studies published (Pillintrip; PMC8365293).
Theoretical risk: immunostimulatory effects could exacerbate autoimmune conditions. No clinical data addressing this specifically. The immune-stimulating mechanism warrants caution.
Immunomodulatory effects could interfere with immunosuppressive regimens. No clinical data (general immunology principles).
No dose-adjustment guidance or dedicated PK studies in renal or hepatic impairment identified. Use with caution and medical supervision.
Talk to Your Doctor
Before considering Thymalin, discuss it with your healthcare provider. Ask about potential interactions with your current medications, whether it is appropriate for your health conditions, and what monitoring may be needed.
Sources: [1-11]
Evidence Assessment
Evidence tier 4 (Phase I/limited human clinical data): (1) No thymalin-specific interventional trials are registered in ClinicalTrials.gov, WHO ICTRP, EU-CTR, or ChiCTR; (2) Clinical evidence consists of small controlled studies (n=36-50 per arm), non-randomized comparative studies, case reports (n=2), and a meta-analysis of 4 older RCTs, all from Russian literature without formal phase designations; (3) No studies report formal effect sizes with confidence intervals; (4) A Cochrane systematic review of thymic peptides in cancer found no clear survival benefit but some reduction in severe infections (PMC6481824); (5) Trials were small, unblinded, and may have underreported events; (6) Most studies are authored by the developer group (potential COI). The overall evidence quality is low-to-moderate by Western regulatory standards.
1Peptide Drug Thymalin Regulates Immune Status in Severe COVID-19 Older Patients
Kuznik B.I. et al. - Advances in Gerontology (2021) - Controlled clinical study (non-randomized) - 80 (36 thymalin + standard therapy; 44 standard therapy only)
Thymalin plus standard therapy showed faster clinical improvement, recovery from lymphopenia, faster normalization of CRP and D-dimer, increased NK-cell counts, and approximately 50% lower in-hospital mortality versus standard therapy alone.
Limitations: Not registered in international trial registries; no formal effect sizes or CIs; non-randomized; non-blinded; small sample.
2Effect of Thymalin on Cellular and Humoral Immunity and Quality of Life in Elderly Patients with COVID-19
Khavinson V.K. et al. - Vrach (The Doctor) (2021) - Controlled clinical study - 88 (38 thymalin; 50 control)
5.95-fold decrease in IL-6, 2.15-3.73-fold increases in lymphocyte subsets, approximately 4.25-fold higher IgG at 200 days post-treatment versus control.
Limitations: Non-randomized; no formal CIs; Russian-language publication.
3Effect of Thymalin on Adaptive Immunity in Complex Therapy for Patients with COVID-19
Khavinson V.K. et al. - CyberLeninka (2020) - Controlled clinical study - 10 (thymalin subgroup)
Thymalin group showed smaller decline in anti-SARS-CoV-2 IgG: 21% decline at 104 days vs 53% decline in standard therapy group.
Limitations: Very small sample size (n=10 subgroup); no CIs or formal statistics.
4Thymalin as a Potential Alternative in the Treatment of Severe Acute Respiratory Infection Associated with SARS-CoV-2
Lukyanov S.A. et al. - International Journal of Immunology and Immunotherapy (2020) - Case report - 2
Both patients experienced marked clinical and laboratory improvement.
Limitations: Case report level (n=2); no control group.
5Thymalin: Activation of Differentiation of Human Hematopoietic Stem CellsPMID 33237528
Khavinson V.K. et al. - Bulletin of Experimental Biology and Medicine (2020) - In vitro experimental study - N/A (cell culture)
Thymalin activated differentiation of human HSCs (reducing CD44/CD117, increasing CD28 on T cells).
Limitations: In vitro only; no human clinical confirmation.
6The Use of Thymalin for Immunocorrection and Molecular Aspects of Biological Activity
Khavinson V.K., Linkova N.S., Chalisova N.I., Ivko O.M. - Biology Bulletin Reviews (2021) - Comprehensive review - N/A (review)
Comprehensive review of thymalin molecular mechanisms, clinical applications, and biological activity of component peptides.
Limitations: Review article; primarily authored by the thymalin development group (potential COI); limited independent replication.
7The 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
Linkova N.S. et al. - International Journal of Molecular Sciences (2023) - In vitro transcriptomic/proteomic study - N/A (PBMC cell culture)
KE and EW dipeptides modulated NF-kB and PI3K/Akt pathway nodes. Reduced LPS-induced pro-inflammatory cytokines by approximately 1.4-6.0-fold.
Limitations: In vitro study; clinical translation not confirmed.
8Peptides of Pineal Gland and Thymus Prolong Human LifePMID 14523363
Khavinson V.K., Morozov V.G. - Neuro Endocrinology Letters (2003) - Longitudinal clinical/observational study - Elderly cohorts (exact n varies by endpoint)
Combined thymalin + epithalamin treatment associated with reduced mortality and improved physiological indices over multi-year follow-up.
Limitations: Observational; limited methodological detail in accessible sources.
9Meta-Analysis of Immunomodulatory Activity of the Medicinal Peptide Preparation Thymalin
Not specified in accessible abstract - CyberLeninka - Meta-analysis of 4 RCTs - Pooled from 4 RCTs (total not specified)
Statistically significant increase in initially reduced T-lymphocyte counts; effect classified as large (SMD > 0.8).
Limitations: Individual trial CIs not consistently reported; older Russian RCTs.
10Thymic peptides for treatment of cancer patients (Cochrane/systematic review)
Wolf E et al. - Cochrane Database of Systematic Reviews (2011) - Systematic review - Pooled across multiple thymic peptide trials
No clear survival benefit for thymic peptides in cancer. Some reductions in severe infections. No carcinogenic signal.
Limitations: Includes multiple thymic peptides (not thymalin-specific); heterogeneity.
11Effect of Thymalin on Clinical Course and Lipid Peroxidation in Children with Chronic Gastroduodenitis
Not specified in accessible text - CyberLeninka (2005) - Comparative clinical study - 34 pediatric patients; 20 healthy controls
Thymalin group had faster symptomatic improvement and normalization of lipid peroxidation markers.
Limitations: Small sample; no between-group effect sizes or CIs; pediatric population.