Thymulin
Also known as: Facteur thymique serique, FTS
Thymulin (also called Facteur thymique serique or FTS) is a thymic nonapeptide. Thymulin is a nonapeptide secreted by thymic epithelial cells whose defining feature is an absolute requirement for zinc: the peptide is biologically inactive until a zinc ion binds and fixes it in the active conformation, so circulating activity tracks zinc status as well as peptide concentration.
For research use only.
Key Facts
- CAS
- 63958-90-7
- Molecular Weight (MW)
- 858.9 g/mol
- Half-life
- —
- FDA status
- Not Approved
- Administration Route
- Subcutaneous
- Frequency
- Research-dependent
- Last updated
- Aug 30, 2026
- Reviewed
- Aug 30, 2026
- Targets
- T-cell differentiation pathways
Vendor price snapshot
Price per mg is list price divided by vial size in milligrams when both are known from public vendor listings. Peptide Library does not sell peptides. Confirm live prices on the vendor site.
- Vendors listing this peptide
- 2
- Listed offers
- 2
- Price per mg range
- $6.00–$59.50/mg
Research summary
Zinc-dependent thymic nonapeptide, also called facteur thymique serique, secreted by thymic epithelial cells. It is biologically inactive until zinc binds and fixes it in the active conformation, so its activity tracks zinc status as well as peptide concentration. It has been studied for T-cell differentiation and, separately, for anti-inflammatory and antinociceptive effects in animal models. Circulating levels fall with age as the thymus involutes. Not FDA-approved as a drug.
Peptide Library's Thymulin profile summarises 5 cited studies listed in the Science section, the compound's regulatory status, and research-protocol parameters reported for it. It is a research reference, not medical advice.
Protocol
- Dosage Range
- Not established as a US drug
- Frequency
- Research-dependent
- Cycle
- —
- Administration Route
- Subcutaneous
- Reconstitution Guide
- —
- Injection Sites
- AbdomenThigh
- Timing Notes
- Educational catalog only — not medical advice
Not yet checked against primary sources
These figures are compiled from earlier reference material. They have not been verified against FDA labelling, registered trials or published literature, no citation is attached to them, and none of them is a recommended dose. Thymulin is queued for dosage evidence review.
Compare reported doses across the whole librarySequence & molecular data
| Amino acid sequence | Pyr-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn |
|---|---|
| Molecular formula | C33H54N12O15 |
| Molecular weight | 858.9 g/mol |
| CAS number | 63958-90-7 |
| Appearance | White lyophilized powder |
| Formulation | Lyophilized Powder |
| PubChem CID | 71300623 |
Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.
Science
Mechanism of Action
Thymulin is a nonapeptide secreted by thymic epithelial cells whose defining feature is an absolute requirement for zinc: the peptide is biologically inactive until a zinc ion binds and fixes it in the active conformation, so circulating activity tracks zinc status as well as peptide concentration. In its active form it promotes T-cell differentiation and maturation, influences the balance of T-cell subsets, and modulates cytokine production. Separately it has been reported to have anti-inflammatory and antinociceptive activity in animal models through effects on neuroimmune signalling. Circulating thymulin falls with age as the thymus involutes. There are no controlled human efficacy trials.
Origin
Endogenous nonapeptide; synthetic research material.
Targets
Studies
- Role of thymulin or its analogue as a new analgesic molecule
- Thymulin restrains age-associated myeloid inflammation and enhances cancer immunotherapy
- Thymus-derived hormonal and cellular control of cancer
- Precursors of thymic peptides as stress sensors
- Thymulin (Zn-facteur thymique serique) activity in anorexia nervosa patients
Regulatory & research status
Thymulin is not an FDA-approved product. It is sold for laboratory research and has no approved medical use.
| FDA status | Not Approved |
|---|---|
| Availability | Research-Only |
| WADA (sport) | Unknown / Not Listed |
| Library classification | Research-Only |
Benefits
Potential Side Effects
Side Effects
- Limited modern safety data
Storage & stability
Lyophilized (freeze-dried) peptide powder is far more stable than the reconstituted solution. Keep sealed vials cold, dry and away from light; long-term storage is typically frozen, with short-term refrigeration for vials in use.
Once reconstituted in bacteriostatic water, keep the solution refrigerated, avoid repeated freeze–thaw cycles and agitation, and label the vial with the reconstitution date and concentration. Discard any solution that turns cloudy or shows particulates.
Degradation rates differ by sequence: peptides containing methionine, cysteine, asparagine or glutamine are more prone to oxidation and deamidation, so shelf life after reconstitution is compound-specific rather than universal.
Read the full guide: how to store peptides before and after reconstitution →
Source: Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575. (PMID 20143256). General guidance for research handling; not product-specific instructions.
Thymulin: frequently asked questions
What is Thymulin?
Zinc-dependent thymic nonapeptide, also called facteur thymique serique, secreted by thymic epithelial cells. It is biologically inactive until zinc binds and fixes it in the active conformation, so its activity tracks zinc status as well as peptide concentration. It has been studied for T-cell differentiation and, separately, for anti-inflammatory and antinociceptive effects in animal models. Circulating levels fall with age as the thymus involutes. Not FDA-approved as a drug.
How does Thymulin work?
Thymulin is a nonapeptide secreted by thymic epithelial cells whose defining feature is an absolute requirement for zinc: the peptide is biologically inactive until a zinc ion binds and fixes it in the active conformation, so circulating activity tracks zinc status as well as peptide concentration. In its active form it promotes T-cell differentiation and maturation, influences the balance of T-cell subsets, and modulates cytokine production.
Is Thymulin FDA approved?
No. Thymulin is not approved by the FDA for any indication and is categorised as research-only. It has not been reviewed for safety or efficacy as a medicine, and published research should be read as investigation rather than established use.
What is the amino acid sequence of Thymulin?
Thymulin has the sequence Pyr-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn, giving a chain of 9 amino acids. Its molecular formula is C33H54N12O15.
What peptides are similar to Thymulin?
Compounds most often compared with Thymulin include Thymosin Alpha-1, Thymalin, Thymogen (Oglufanide) and Thymopentin. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.
References
- Role of thymulin or its analogue as a new analgesic molecule — Ann N Y Acad Sci, 2006External reference
- Thymulin restrains age-associated myeloid inflammation and enhances cancer immunotherapy — Nat Commun, 2026External reference
- Thymus-derived hormonal and cellular control of cancer — Front Endocrinol (Lausanne), 2023External reference
- Precursors of thymic peptides as stress sensors — Expert Opin Biol Ther, 2020External reference
- Thymulin (Zn-facteur thymique serique) activity in anorexia nervosa patients — Am J Clin Nutr, 1985External reference
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Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Aug 30, 2026 · Version 1
This Thymulin profile is compiled from published literature (5 cited studies linked above), public regulatory records and chemical registries. It describes what research reports; it is not medical advice, and nothing here is a dosing recommendation for humans. Peptide Library does not sell peptides. Editorial policy · How profiles are compiled · Report an error
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