Immune & ThymicTarget: ThymusImmune

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.

Not FDA-approved - research chemical

Quick answer

What it is: Thymulin (facteur thymique sérique, FTS) is a zinc-dependent nonapeptide thymic hormone from a French discovery path.

Class and target: Stability analog (not a Khavinson original) · Thymus (circulating thymic hormone)

Typical research dose: 1-5 mg/day

Reconstitution calculator ↓

Research summary, not medical advice.

Reviewed by Kymata Health Editorial Team

·Last updated: August 2026·Evidence: Low

Typical research dose

1-5 mg/day

Frequency

1× daily for 10-30 day cycles

Half-life

Short (peptide)

Common vials

5 mg / 10 mg

CAS

75968-11-5

Molecular weight

857.85 g/mol (apo-form)

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

Dose it

5 mg + 2.5 mL BAC water → 2 mg/mL · 1000 mcg ≈ 50 units (U-100)

Open in calculator

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: 2657247

Khavinson map

Adjacent (not padded into the 41)

Class

Stability analog (not a Khavinson original)

Organ

Thymus (circulating thymic hormone)

Target

Thymus

System

Immune

Sequence

Mixture / not a single CAS

Pair

Neighbor immune peptides - not a Khavinson cytogen SKU

Тимулин

The Khavinson school

Thymulin is filed here as stability analog (not a khavinson original), targeting the thymus (circulating thymic hormone). Khavinson's St. Petersburg group moved from organ extracts (Cytamins) to capsule complexes (Cytomaxes) to synthetic short peptides (Cytogens); most of the evidence comes from that one group, with little independent Western replication.

Read the full background, the proposed epigenetic mechanism, the literature limits, and how we count the canonical 41 on the Khavinson bioregulators index.

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

Route / form

Research nonapeptide (FTS). Typical presentation is a lyophilized vial for subcutaneous research use. Not Thymalin (CIS IM extract), not Thymogen (EW), not a Cytomed capsule, and not a sublingual tablet.

Timing

Research vial (SubQ): food does not change the injection. Not a Cytomed capsule course.

Empty stomach?

No - These are research vials, not Cytomed capsules. Food timing does not apply to SubQ.

Thymulin: oral vs SubQ

Research FTS vial

Bioavailability

Research SubQ of the zinc-dependent nonapeptide FTS (facteur thymique sérique). French discovery path, not a Khavinson Cytamin ampoule.

Dose note

Vendor research vials exist (often 5–10 mg cakes). Classical biology is nanogram-to-microgram range with zinc; gray-market milligram schedules are not Bach’s FTS papers. Not a Thymalin 10 mg IM extract chart. Apo-thymulin is inactive until it binds Zn2+.

Advantages

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.

Considerations

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.

No Cytomed capsule

Bioavailability

There is no Cytomed Thymulin capsule. Vladonix is thymus Cytomax. Thymogen is EW capsules. Swallowing those is not FTS. Do not invent an oral FTS Cytomed SKU.

Dose note

If the bottle is oral, you bought a different thymus product. No honest Thymulin capsule course on this leaf.

Advantages

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.

Considerations

Name collision with Thymalin/Thymogen is how the wrong bottle ships.
Zinc pills are not a Thymulin dose.
Not a sublingual immune melt.

Recommendation: Thymulin is FTS, a zinc-dependent nonapeptide, typically a research SubQ vial. It is not in the 41. It is not Thymalin (IM extract), not Thymogen (EW, capsule-or-vial), not Vilon, not Vladonix, and not a Cytomed capsule. Do not tag it as a pharmaceutical extract.

Timeline

Week 1-4

Improved T-cell counts and NK cell activity in immunocompromised individuals.

Month 1-3

Improved immune function markers. Reduced infection frequency in elderly study populations.

Who it is for

Immune Senescence

Low

Restores thymic peptide signaling in aged immune systems. Works synergistically with zinc repletion.

T-Cell Immunology

Low

Mediates 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

FDA Status (US)

Research Only

WADA Status (2026)

Not Listed

Not currently on the WADA 2026 Prohibited List. Policies may change - verify before competition.

Classification

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

+ Thymalin →

Thymulin (circulating thymic hormone) + Thymalin (thymic polypeptide extract) provide complementary thymic support through different mechanisms - Thymulin acts systemically, Thymalin acts directly on thymic tissue.

+ Vilon →

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?▼

No. French FTS line. We document it because buyers confuse the names.

Vs Thymalin / Thymogen?▼

Nonapeptide hormone vs thymus extract vs EW dipeptide.

Why zinc?▼

Apo-thymulin is inactive until it binds Zn2+. That is textbook FTS, not a supplement upsell.

TA-1?▼

Still no.

Capsule or shot?▼

Research vial / SubQ. There is no Cytomed Thymulin capsule. Vladonix is thymus Cytomax; Thymogen is EW; Thymalin is IM extract. Not a sublingual tablet.

Does thymulin require zinc?▼

Yes - thymulin is biologically active only when bound to one zinc ion. Zinc deficiency renders thymulin inactive. Both peptide replacement and zinc optimization are required for full thymulin activity.

How does thymulin differ from thymalin?▼

Thymalin is a polypeptide extract from the full thymus gland (Khavinson protocol). Thymulin (FTS) is a single specific 9-AA thymic peptide with known structure. Thymulin has more specific T-cell differentiation activity; thymalin provides broader thymic peptide signaling.

Where to get itOral bioregulator

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Thymusol is Vita-Stream's US-made thymus bioregulator (Vita Peptides' own house line), a different product from Thymulin. No trial has tested it.

Browse Thymusol

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See all sources and our full review

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