The Russian-developed thymic polypeptide extract — related to but distinct from Thymosin Alpha-1, with decades of Eastern European clinical use in immune restoration and longevity protocols.
Thymalin is a Russian-developed polypeptide extract from bovine thymus gland — a mixture of short peptides rather than a single molecule. Developed at the St. Petersburg Institute of Bioregulation and Gerontology (Khavinson’s group), it’s been used in Russian clinical practice since the 1970s for immune restoration.
Related to but distinct from Thymosin Alpha-1 (which is a single defined 28-amino-acid peptide). Thymalin is a complex extract — less reproducible molecule-for-molecule but with decades of clinical data behind it in its target population.
Approved in Russia. Not FDA approved. Not WADA prohibited. Available through Russian pharmacies and research-peptide suppliers.
Like Thymosin Alpha-1, Thymalin supports maturation of naive T-cells into functional effector cells — compensating for age-related thymic involution that begins in puberty.
Unlike the defined-molecule Tα1, Thymalin delivers a cocktail of thymic peptides. Believed to produce a broader immune-restoration effect but with less precision. Khavinson’s bioregulator framework describes this as "signaling molecules" supporting thymic function rather than a single pharmacological effect.
Shifts Th1/Th2/Treg balance toward age-appropriate regulatory tone. Useful in chronic infection and immune exhaustion contexts.
| Benefit | Evidence |
|---|---|
| Immune restoration | Long-standing Russian clinical use; improved T-cell counts and function in elderly cohorts |
| Mortality reduction | The specific source is Khavinson & Morozov 2003 (PMID 14523363): 266 elderly subjects followed 6–8 years, treated for the first 2–3. Reported mortality fell 2.0–2.1-fold with Thymalin alone, 1.6–1.8-fold with the pineal extract Epithalamin, 2.5-fold combined, and 4.1-fold in a group given both annually for six years. Acute respiratory disease incidence fell 2.0–2.4-fold. Note what it is before weighing it: open-label, one institution, one research lineage, no independent replication, and a 4.1-fold mortality reduction is an extraordinary claim on a design that cannot support it. Note also that the comparator arm here used Epithalamin, the crude pineal extract, not Epitalon — see the Epitalon guide, where the same distinction changes the dosing by a factor of 500. |
| COVID-19 adjunct | Added to standard therapy, Thymalin accelerated the decline in IL-6, C-reactive protein and D-dimer and improved T-cell indices versus standard therapy alone (PMID 33575961). Mortality figures circulate for this work; what the indexed paper documents is marker normalisation, so that is what is stated here. |
| Stem-cell differentiation (in vitro) | In human hematopoietic stem cells, Thymalin cut expression of CD44 (stem-cell marker) and CD117 (intermediate differentiation) by 2–3× while raising CD28 (mature T lymphocyte) 6.8× — the clearest mechanistic evidence that it pushes precursors toward functional T cells (Khavinson 2020, PMID 33237528). |
| Chronic infection adjunct | Used in Russian HIV, hepatitis B/C, and chronic viral protocols |
| Age-related decline | Marketed in Russia as a longevity bioregulator |
Most evidence is Russian cohort data; Western RCT replications are limited. Thymosin Alpha-1 has far more Western clinical validation for the same general use cases.
Thymalin is not one molecule, which changes how to read all of the above. It is a polypeptide extract of thymus, and its active substances are the dipeptides KE (Lys-Glu) and EW (Glu-Trp). They do different things: KE stimulates cellular immunity and acts on macrophages, lymphocytes, thymocytes and neutrophils, while EW reduces angiotensin-induced vasoconstriction and preserves endothelium-dependent relaxation (PMID 37686182). Both are reported to enter the nucleus and bind double-stranded DNA. So “Thymalin” names a preparation whose composition can vary between sources, not a defined compound at a defined dose — the same problem that separates Epithalamin from Epitalon.
Build your protocol, log every dose, monitor your body's response, and get reminders so you never miss a dose.
Start Tracking FreeNot medical advice. These figures describe what is reported in the literature and what practitioners and communities do — not a recommendation, and for most compounds here no human dose-finding study exists. Talk to a qualified healthcare provider.
This page previously gave 10–20 mg over 10–20 days. It is now 10 mg daily for 10 days because that is the protocol the clinical work actually used, rather than a range built around it. Nothing published supports the 20 mg end, and for a preparation whose composition is not standardised between sources, inventing headroom above the studied dose is the wrong direction to guess in.
If you have a choice between the two, Tα1 is generally preferred for Western users — single defined molecule, better Western clinical validation, more reliable batch-to-batch. Thymalin is useful if you’re specifically following a Russian bioregulator protocol alongside Epitalon and other Khavinson peptides.
Not medical advice. These figures describe what is reported in the literature and what practitioners and communities do — not a recommendation, and for most compounds here no human dose-finding study exists. Talk to a qualified healthcare provider.
10 mg vial + 2 mL BAC water = 5 mg/mL
| Dose | Volume | Syringe Units |
|---|---|---|
| 10 mg | 2.00 mL | Full 2 mL IM |
| 20 mg | Use undiluted or larger vial | — |
Pre-filled with a typical Thymalin setup. Edit any field — the draw updates live.
Insulin syringe — 100 units = 1 mL
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Generally very well tolerated. Decades of Russian clinical use with minimal reported adverse events.
Thymalin is a research peptide not approved by the FDA for human use. It is sold only as a research chemical, and StackTrax does not endorse or facilitate personal use.
Quality varies enormously among research-chemical suppliers. At minimum, look for:
Lyvn does not carry Thymalin. They are the vendor we recommend elsewhere on this site, and they publish the full independent panel per batch — which makes their catalogue a useful yardstick for the criteria above even on a compound they do not stock. We are not recommending a specific supplier for Thymalin itself, because we have no basis to.
For research use only. Not for human consumption. 21+.
Build your protocol, log every dose, monitor your body's response, and get reminders so you never miss a dose.
Start Tracking FreeThymalin is a Russian-developed polypeptide extract from bovine thymus gland, a mixture of short peptides rather than a single defined molecule. It was developed at the St. Petersburg Institute of Bioregulation and Gerontology (Khavinson's group) and has been used in Russian clinical practice since the 1970s for immune restoration. It is related to but distinct from Thymosin Alpha-1, which is a single 28-amino-acid peptide.
Like Thymosin Alpha-1, Thymalin supports maturation of naive T-cells into functional effector cells, compensating for age-related thymic involution that begins at puberty. Because it is a multi-peptide cocktail rather than a defined molecule, it is believed to produce a broader immune-restoration effect with less precision. Khavinson's bioregulator framework describes this as signaling molecules supporting thymic function rather than a single pharmacological effect, and it appears to shift Th1/Th2/Treg balance toward age-appropriate regulatory tone.
The 20-year Russian cohort data report that combined Thymalin plus Epitalon was associated with reduced all-cause mortality in older adults, and improved T-cell counts and function in elderly cohorts. Thymalin is also used in Russian HIV, hepatitis B/C, and chronic viral protocols. Most of the evidence is Russian cohort data; Western RCT replication is limited, and Thymosin Alpha-1 has far more Western clinical validation for the same general use cases.
No. Thymalin is approved in Russia but is not FDA approved. It is not WADA prohibited. It is available through Russian pharmacies and research-peptide suppliers.
The standard Russian protocol is 10 to 20 mg IM, daily or every other day, in 10 to 20 day cycles run 2 to 4 times per year. For reconstitution, a 10 mg vial plus 2 mL bacteriostatic water gives 5 mg/mL, so a 10 mg dose is the full 2 mL IM. Reconstituted product should be refrigerated and used within 10 to 14 days.
Thymalin is generally very well tolerated, with decades of Russian clinical use and minimal reported adverse events. Common mild effects include injection site reactions, transient low-grade fever from immune activation, and mild fatigue in the first few days. Avoid in pregnancy entirely: PMID 2800803 describes prenatal Thymalin administration in neurosensitized rats affecting offspring cerebral cortical neurons, a specific fetal neurological signal. Use caution with active autoimmune flare, breastfeeding, or known bovine protein sensitivity; avoid in organ transplant recipients due to theoretical rejection risk.
Thymalin is a multi-component polypeptide extract from bovine thymus (Khavinson lineage). Thymulin is a single 9-amino-acid zinc-dependent synthetic nonapeptide (Bach lineage, 1977). Thymosin Alpha-1 is a single defined 28-amino-acid peptide approved in 35+ countries. If you have a choice, Tα1 is generally preferred for Western users because it is a single defined molecule with better Western clinical validation and more reliable batch-to-batch consistency. Thymalin is useful if you are specifically following a Russian bioregulator protocol alongside Epitalon and other Khavinson peptides.
Disclaimer: This guide is for educational and informational purposes only and is not intended as medical advice, diagnosis, or treatment. The compounds discussed are not FDA approved for human use. Always consult a qualified healthcare provider before starting any new supplement or peptide protocol. StackTrax does not sell peptides or supplements directly — purchase links go to third-party vendors. StackTrax is not responsible for the products, quality, or business practices of any third-party vendor.
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StackTrax guides cover peptides and compounds that are not FDA-approved for the uses discussed. The dosing, reconstitution, and safety information is compiled from published research and community protocols for educational purposes only.
Before using any compound mentioned here, consult a qualified healthcare provider. StackTrax does not sell, prescribe, or recommend these substances for personal use.