Thymulin
Facteur Thymique Sérique · FTS · Thymuline · Serum Thymic Factor · Тимулин
Thymulin (facteur thymique sérique, FTS) is a zinc-dependent nonapeptide thymic hormone from a French discovery path. Adjacent immune biology, not one of the 41 Khavinson SKUs. Do not merge with Thymalin or Thymogen.
Use-case scores
0–10 against the evidence we have, not a gym ranking. Hidden domains do not apply here.
- Immune3/10
Historical thymic hormone. Not thymosin α1 / Zadaxin. Not Thymalin extract.
Compound card
- Class
- Nonapeptide thymic hormone (FTS; zinc-dependent)
- Formula
- C33H54N12O15 (apo-form)
- Status
- Not FDA-approved · research use
How it works
Thymulin (Facteur Thymique Sérique / FTS) is a 9-amino-acid thymic peptide that requires zinc binding to be biologically active. It is produced by thymic epithelial cells and is a key mediator of T-cell differentiation and maturation, specifically promoting CD4/CD8 T-cell development and NK cell activity.
Thymulin levels decline markedly with age and zinc deficiency - both reduce immune competence. Thymulin supplementation (either as the peptide or via zinc repletion to restore endogenous activity) has been studied for immune senescence, cancer immunotherapy support, and inflammatory disease. It is a member of the Khavinson bioregulator peptide family, representing a complementary approach to Thymalin.
Source: PMID: 3299395
Khavinson map
Adjacent (not padded into the 41)The Khavinson school
Vladimir Khatskelevich Khavinson (1946–2024) spent five decades at what became the St. Petersburg Institute of Bioregulation and Gerontology arguing a simple, stubborn idea: aging is, in part, a failure of tissue-specific peptide signals, and those signals can be restored. The first products were not “peptides” in the Instagram sense. They were Cytamins - polypeptide fractions isolated from a named organ of young animals. Later commercial refinements of those fractions are sold as Cytomaxes (Cytomed / NPCRIZ): still mixtures, still oral capsules, still defined by the source organ rather than a single sequence. When the group identified short active motifs inside those mixtures, they synthesized them as Cytogens - di-, tri-, and tetrapeptides with a one-letter code (KE, AEDG, KED, EDR, KEDP, and so on).
That three-layer stack is the whole map. Cytamin / pharmaceutical extracts (Thymalin, Epithalamin, Cortexin, Retinalamin, Prostatilen) are the clinic-era injectables registered in the former Soviet pharmacopeia. Cytomaxes are the capsule complexes Cytomed still lists as a 21-SKU organ line. Cytogens are the defined synthetics. English-language educators, including Brenden Henry’s public writing at Peptide Science Institute, add a further commercial distinction - later analog SKUs (N-acetyl, amidate, “V2” complexes) sold as more stable or more diverse than the original Cytomed lots. That last layer is a product taxonomy, not a Khavinson paper. We describe it so readers are not gaslit by three bottles with the same organ name. We do not reproduce paid Peptide Mastery protocols, Precision Cell Method language, or anyone else’s course IP.
Full Cytamin → Cytomax → Cytogen map, literature limits, and how we counted 41
The mechanism Khavinson published is epigenetic, not receptor-agonist in the GLP-1 sense. Short peptides are claimed to enter nuclei, interact with DNA/histones, and reopen tissue-specific transcription that condensed with age (heterochromatin → euchromatin). Reviews in the Bulletin of Experimental Biology and Medicine and Neuroendocrinology Letters (PMID 14523363, 15677927, 23888677) are the citable core. Complementary GI pharmacology is not mystical: di- and tripeptides are PEPT1/LAT substrates, which is why oral capsules are even a conversation. What is not established in Western Phase 3 programs is organ-by-organ disease treatment, telomere reversal as a clinical endpoint, or the manufacturer claim that Cytomax is “a third stronger” than Cytogen. Those are NPCRIZ marketing sentences.
Khavinson’s group published hundreds of papers, many in Russian, many in the same journal family. That is a real literature. It is also a literature with limited independent Western replication, small n, and a habit of using one review PMID as a stamp on every organ. On this site a leaf earns its organ story, its Cytomax↔Cytogen pair, its sequence if it has one, and an honest sentence about what has not been shown. Reconstitution math belongs on cytogens sold as vials. Cytomax capsules do not get a fake 5 mg vial.
The 41 we treat as canonical are the 21 Cytomaxes on the public e-peptide/Cytomed list, the 12 Cytogens on that same commercial line (including Vesilut, which Western catalogs often drop), plus eight historically load-bearing molecules that sit beside the capsule SKUs: Epitalon, Vilon, Thymogen, Livagen, Cortagen, Prostamax, Thymalin, and Epithalamin. Honluten, Cortexin, Retinalamin, Prostatilen, Thymulin, N-acetyl-epitalon-amidate, Pinalex, and the GPL Man / GPL Femme kits are covered as adjacent - same school or same storefront, not padded into a fake 41.
Public English-language teaching (including Brenden Henry at peptidescienceinstitute.com) is cited as context, not copied. Paid Peptide Mastery / Peptide Salvation text stays theirs.
History of this molecule
Bach’s FTS/thymulin is real endocrinology: a nine-residue peptide that needs zinc to work, produced by thymic epithelium, collapsing with involution. Khavinson’s extracts and dipeptides are a different research program that also cares about the thymus. Our library lists both. The 41 does not absorb FTS just to hit a round number.
Caveats
Not Thymalin. Not EW. Not TA-1.
Full 41-map: Khavinson bioregulators index · Bioregulator stacks
Research Use Cases
- ✓Immune reconstitution after thymic involution
- ✓Zinc-thymulin immunotherapy research
- ✓Immunosenescence biomarker (serum levels indicate thymic function)
- ✓Anti-aging immune protocols targeting thymic restoration
Dosing
| Phase | Dose | Frequency | Notes |
|---|---|---|---|
| Immune Support Protocol | 40 - 200 ng/kg | Daily SC (research dosing) | Extremely low doses (nanogram range). Zinc co-administration enhances biological activity. Based on research studies. |
Administration
Thymulin: oral vs SubQ
- Defined nonapeptide (when the COA is FTS). Reconstitution math can exist for a research cake.
- Identity is the whole job: not Thymalin, not Thymogen, not TA-1, not TB-500.
- Zinc status is textbook FTS, not a stack slogan.
- Not in the canonical 41. Analog/adjacent, not a Cytomed cytogen SKU.
- Not a CIS pharmaceutical extract. Do not file it next to Thymalin IM.
- No US immune-deficiency label.
- Refusing a fake oral SKU is the useful sentence.
- Keeps FTS from being sold as “oral Thymalin.”
- Not a sublingual tablet. Nobody manufactures this SKU that way.
- Name collision with Thymalin/Thymogen is how the wrong bottle ships.
- Zinc pills are not a Thymulin dose.
- Not a sublingual immune melt.
Timeline
Who it is for
Immune Senescence
LowRestores thymic peptide signaling in aged immune systems. Works synergistically with zinc repletion.
T-Cell Immunology
LowMediates T-cell differentiation and maturation. Research-level use in cancer immunotherapy support.
Reconstitution
| Vial | Water | Concentration | Example dose |
|---|---|---|---|
| 5 mg lyophilized | 2.5 mL BAC | 2 mg/mL | Research nonapeptide math. Zinc status is part of the classical biology, not a stack slogan. |
Change vial size or water volume? Open the reconstitution calculator.
Safety & Considerations
Research peptide. Active only when bound to zinc. Ensure zinc sufficiency for full activity. Very low doses used. No significant toxicity reported in research studies.
Regulatory & Legal Status
Not currently on the WADA 2026 Prohibited List. Policies may change - verify before competition.
Research Chemical
US Compounding: Not eligible / not available
⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.
Limits of current evidence
- Identity: thymulin ≠ thymosin α1 ≠ thymosin β4 ≠ Thymalin.
- This site will not treat immunodeficiency from this page.
Verdict
Thymulin (facteur thymique sérique) is a nine-residue zinc-dependent thymic peptide. It is not thymalfasin and not the bovine thymic extract. Immune folklore is not a vaccine or infection protocol.
Interactions & Contraindications
REQUIRES zinc supplementation for biological activity - Zn-thymulin complex is the active form. May overstimulate immune system in autoimmune conditions. Not to be combined with immunosuppressive drugs without supervision. Well-characterized safety across decades of research.
Synergies & Common Stacks
Thymulin (circulating thymic hormone) + Thymalin (thymic polypeptide extract) provide complementary thymic support through different mechanisms - Thymulin acts systemically, Thymalin acts directly on thymic tissue.
Thymulin (immune hormone) + Vilon (synthetic thymic dipeptide bioregulator) target immune function through different molecular pathways - circulating hormone vs. epigenetic gene regulation.
Frequently Asked Questions
Is Thymulin a Khavinson 41 peptide?▼
Vs Thymalin / Thymogen?▼
Why zinc?▼
TA-1?▼
Capsule or shot?▼
Does thymulin require zinc?▼
How does thymulin differ from thymalin?▼
References
- Bach JF et al. / related reviews “Thymulin (FTS) as a zinc-dependent thymic hormone.” Immunology / related (1980s–1990s). PMID: 3299395
- Dardenne M, Bach JF “"Thymulin: a thymic factor for immune development".” Annals of the New York Academy of Sciences (1975). PMID: 1060378
Get Thymulin from Vita-Stream - a distributor for Khavinson-line oral capsules. No reconstitution math on a Cytomax bottle.
Affiliate link · Full review