--- title: "Thymalin: what sources report" url: https://humanpeptides.fyi/peptides/thymalin site: humanpeptides.fyi last_reviewed: 2026-10-11 --- # Thymalin > humanpeptides.fyi makes no claims of its own. Every statement below reports what a cited source says, with its link. Not medical advice. Thymalin: Polypeptide extract from calf/bovine thymus developed by Khavinson (St. Petersburg) as an immunomodulator/'peptide bioregulator'. The sources cited here most often discuss it for: Immune restoration, small trial; Longevity claim; Stem cell activation, lab. Evidence label: Early human. ## At a glance - **Type:** Peptide - **Family:** Immune & Gut - **Evidence label:** Early human (3 of 5) - **Regulatory status:** Approved for medical use in the Soviet Union by 1982 and still approved and widely used in Russia, Ukraine and other Eastern European countries, thymalin is not approved for human therapeutic use by the FDA or EMA. - **Goals discussed:** Immunity, Longevity & Cellular Aging - **Also called:** Timalin, thymus polypeptide complex, calf thymus extract - **Last reviewed:** 2026-10-11 ## What is Thymalin? - Polypeptide extract from calf/bovine thymus developed by Khavinson (St. Petersburg) as an immunomodulator/'peptide bioregulator'; approved in Russia for immune deficiency; NOT FDA-approved. Sources: , Not the same as thymulin (a zinc-dependent thymic hormone), thymosin alpha-1 (thymalfasin), or thymogen (the Glu-Trp dipeptide originally isolated from thymalin and sold as a separate drug). **Regulatory status:** Approved for medical use in the Soviet Union by 1982 and still approved and widely used in Russia, Ukraine and other Eastern European countries, thymalin is not approved for human therapeutic use by the FDA or EMA. Source: ## What is Thymalin researched for? ### 1. Immune restoration, small trial - Restores immune function (T-cell/lymphocyte counts): in severe older COVID-19 patients, thymalin increased lymphocyte recovery and was associated with lower hospital mortality (19.4% vs 40.9%) (small single-center single-blind RCT) Sources: , - Goals: [Immunity](https://humanpeptides.fyi/objectives/immunity) ### 2. Longevity claim - Longevity claim: elderly given thymalin (± epithalamin) over 6-8 years reportedly had ~2-fold lower mortality (Khavinson human study, poorly reported, not replicated) Sources: , , - Goals: [Longevity & Cellular Aging](https://humanpeptides.fyi/objectives/longevity) ### 3. Stem cell activation, lab - Activates differentiation of human hematopoietic stem cells (in vitro) Sources: - Goals: [Longevity & Cellular Aging](https://humanpeptides.fyi/objectives/longevity), [Immunity](https://humanpeptides.fyi/objectives/immunity) ## What do researchers and users say about Thymalin? > "Thymalin halved hospital mortality in older patients with severe COVID-19." > > Kuznik B, et al., Peptide Drug Thymalin Regulates Immune Status in Severe COVID-19 Older Patients (Advances in Gerontology, 2021). Context: Single-center randomized, single-blind trial in Chita, Russia: 36 older patients given thymalin plus standard therapy versus 44 given standard therapy plus placebo. > "Thymalin and thymogen have practically no side effects and are used for various viral infections." > > Khavinson VKh, et al., The Use of Thymalin for Immunocorrection and Molecular Aspects of Biological Activity. Context: Review written by the research group that developed thymalin; independent safety data are scarce. > "I haven't been sick or had a herpes outbreak since using it either." > > Anonymous user, r/Biohackers, My immune system results using Thymalin. Context: Forum post claiming improved immune biomarkers after a course of thymalin; no independent verification. ## What side effects of Thymalin are reported? - Little published safety data outside Russian literature; animal-derived extract (theoretical allergy/contamination risk) Sources: , - Rare headache, nausea and restlessness (akathisia), plus occasional injection-site redness or swelling, per a summary of the Russian literature. (secondary summary) Sources: - Not studied in pregnancy or breastfeeding. (secondary summary) Sources: ## What do peptide guides say about Thymalin? - **PepEdHub:** PepEdHub describes thymalin as a thymus polypeptide complex said to support T-cell maturation and NK-cell activity, and credits decades of Russian use, largely research by Professor Vladimir Khavinson. - **NCBI PMC:** A 2020 review gives thymalin's Russian registration (LS-000267, 2010) and lists indications including infections, impaired thymus function, and immune suppression after chemotherapy or radiation. - **NCBI PMC:** In older patients with severe COVID-19, adding thymalin was linked to faster recovery from lymphopenia and quicker normalization of C-reactive protein and D-dimer than standard therapy alone. - **Seek Peptides:** Seek Peptides notes critics' concerns about the thymalin longevity data: no blinding, unclear randomization, possible selection bias and no independent Western replication. ## What does the research say, system by system? ### Body & tissues - Thymus/bone marrow: supports hematopoietic stem cell differentiation (in vitro) Sources: ### Hormones & physiology - Immunomodulator: normalizes T-lymphocyte populations and immune status (small human studies) Sources: - Proposed for COVID-19 immune dysregulation (review) Sources: ### Also notable - Promoted as geroprotector alongside epithalamin; largest mortality effect seen only in combination, so cannot be attributed to thymalin alone Sources: , ## How strong is the evidence for Thymalin? **Early human** (3 of 5). Small Russian human studies (one small RCT) mostly from a single research group; not independently replicated (thin) _Small, short, old, unblinded or single-group human studies._ ## Questions about Thymalin ### What is Thymalin? Polypeptide extract from calf/bovine thymus developed by Khavinson (St. Petersburg) as an immunomodulator/'peptide bioregulator'. Not the same as thymulin (a zinc-dependent thymic hormone), thymosin alpha-1 (thymalfasin), or thymogen (the Glu-Trp dipeptide originally isolated from thymalin and sold as a separate drug). ### Is Thymalin FDA-approved? Approved for medical use in the Soviet Union by 1982 and still approved and widely used in Russia, Ukraine and other Eastern European countries, thymalin is not approved for human therapeutic use by the FDA or EMA. ### What is Thymalin researched for? The sources cited on this page most often discuss three outcomes: Immune restoration, small trial; Longevity claim; Stem cell activation, lab. Each line above shows what the source reports and how strong that evidence is. ### What side effects of Thymalin are reported? Reported in the cited sources: Little published safety data outside Russian literature; animal-derived extract (theoretical allergy/contamination risk); Rare headache, nausea and restlessness (akathisia), plus occasional injection-site redness or swelling, per a summary of the Russian literature; Not studied in pregnancy or breastfeeding. The list is not complete, and few listed risks does not mean a compound is safe. ### How strong is the evidence for Thymalin? Evidence label: Early human. Small Russian human studies (one small RCT) mostly from a single research group; not independently replicated (thin). ### What else is Thymalin called? Names used for it include Timalin, thymus polypeptide complex, calf thymus extract. ### Does humanpeptides.fyi recommend Thymalin? No. humanpeptides.fyi makes no claims and no recommendations of its own. It summarizes and links to what others have published and posted. Nothing here is medical advice; talk to a licensed clinician. --- Family: [Immune & Gut](https://humanpeptides.fyi/peptides?cat=immune). HTML version: . Disclaimer: