Peptide LibraryThymulin
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
- FDA compounding lists
- 503A Category 3
- Evidence level
- Limited Human Evidence
- Human dose established
- No
- Administration Route
- Not established in humans
- Frequency
- Not established in humans
- Last updated
- Nov 7, 2026
- Reviewed
- Nov 7, 2026
- Targets
- T-cell differentiation pathways
Vendor price snapshot
Each vendor counts once, at the median price per mg of its own listings; the typical range is the middle half of vendors. From public vendor listings collected between Oct 2026 and Nov 2026, so confirm the live price on the vendor site. Peptide Library does not sell peptides.
- Vendors listing this peptide
- 9
- Listed offers
- 9
- Median price per mg
- $4.25/mg
- Typical $2.58–$6.25/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.
Research evidence
- Regulatory review (FDA label)None in reviewed sources
- Controlled human trials1 reviewed source
- Early or uncontrolled human studies2 reviewed sources
- Lab & animal studiesNone in reviewed sources
How it works
Each step shows whether the sources Peptide Library has reviewed include that kind of research. Counts are reviewed sources, not every study ever published. Reviews and programme summaries that describe human use are shown as "reported", not as trials, and registered trials without published results are listed but not counted. A higher step means research has progressed further; it does not mean a compound works better or is safer. Compounds whose evidence has not been reviewed yet show "Not reviewed" instead of a guess.
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.
Thymulin dosage: no established human dose
Thymulin has no established human dosage. A few small studies in the 1980s gave the synthetic peptide (also called facteur thymique sérique, FTS, or nonathymulin) to people with immune deficiency, rheumatoid arthritis or multiple sclerosis, but their indexed abstracts do not state the dose. The only placebo-controlled trial, in 40 people with multiple sclerosis, found no benefit. Thymulin is not FDA-approved, and no trial is registered on ClinicalTrials.gov.
No established human dosage.
Human clinical evidence: None identified.
Preclinical research: Thymulin is a nine-amino-acid hormone made by the thymus. It only works when bound to zinc, so zinc-thymulin (FTS-Zn) is its active form and the synthetic peptide picks up zinc in the body. Most research is in animals, where it has anti-inflammatory and pain-reducing effects. Many human papers measure the body's own thymulin levels, for example during zinc supplementation; they do not give thymulin and do not provide a dose. The few studies that gave the peptide to people do not state the amount in their indexed records.
Animal dosing is not converted into a human dose anywhere on this page. Where research figures appear below, they are reported as studied, not recommended.
| Human dosing established | No |
|---|---|
| Route | Subcutaneous or intravenous in the indexed human studies |
| Evidence level | Limited Human Evidence |
| Last reviewed | 2026-11-07 |
Human research reported
Doses as studied, one row per regimen. Different trials used different regimens; they are listed separately rather than averaged.
| Study / context | Population | Dose | Route | Frequency | Duration | Outcome studied | Source |
|---|---|---|---|---|---|---|---|
| Nonathymulin (synthetic thymulin) in multiple sclerosis (1989)Clinical trial · Randomised double-blind placebo-controlled pilot trial | Adults with active multiple sclerosis and moderate disability (n=40, matched pairs) | Not stated in the indexed abstract | Subcutaneous | — | 6 months, with 6 months of follow-up | No difference from placebo in disability scores; no significant side effects recorded | Nonathymulin treatment of multiple sclerosis: double-blind pilot study. Acta Neurol Scand. 1989. |
| Synthetic FTS in immunodeficient children (1982)Clinical trial · Uncontrolled case series | Children with IgA and IgE deficiency and T-cell defects (n=3) | Not stated in the indexed abstract | Intravenous | — | — | Fewer and milder infections and better cell-mediated immunity tests reported; gains regressed when treatment paused | Improvement of cellular immunity and IgA production in immunodeficient children after treatment with synthetic serum thymic factor (FTS). Lancet. 1982. |
| Zinc-bound thymulin (FTS-Zn) in rheumatoid arthritis (1987)Clinical trial · Open (uncontrolled) trial | Patients with rheumatoid arthritis (number not stated in the indexed record) | Not stated in the indexed record (no abstract) | Not stated in the indexed record | — | — | Not available in the indexed record | An open trial of thymulin (FTS-Zn) in rheumatoid arthritis patients: sequential clinical and immunological follow-up. Clin Exp Rheumatol. 1987. |
Where sources disagree
- This profile and the zinc-thymulin profile describe the same hormone: thymulin is the peptide, and zinc-thymulin is the peptide with its zinc ion bound. The same human studies apply to both, and none of them states a dose in its indexed record.
- Studies that raised blood thymulin by giving zinc are evidence about zinc, not a dose of thymulin.
- DailyMed lists a homeopathic pellet named after thymulin. It is an unapproved homeopathic product, not an FDA-approved thymulin drug.
Reconstitution
Common research vial sizes: 10 mg, 20 mg.
| Vial | Bacteriostatic water | Concentration | Per 0.01 mL |
|---|---|---|---|
| 10 mg | 2 mL | 5 mg/mL | 50 mcg per 0.01 mL |
| 20 mg | 2 mL | 10 mg/mL | 100 mcg per 0.01 mL |
These figures are arithmetic only — they convert a vial and a volume into a concentration. They are not a recommendation to take any dose.
Calculate reconstitution & dose →Handling & administration
- Injection Sites
- AbdomenThigh
- Timing Notes
- Educational catalog only — not medical advice
Sequence & 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
Research statistics
325 PubMed publications · 18.9% human clinical research · 0 registered trials
Counts of published research through 2026-11-01, not evidence that it works. Publications by year, study types and trials · How publications are counted
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 |
FDA compounding status
These FDA lists track substances nominated for use in pharmacy compounding. Being on a list is not FDA approval and doesn't mean a product is safe or effective.
| 503A Category 3 | Nominated without adequate support FDA source |
|---|
FDA list dated May 14, 2026.
How FDA approval, compounding and research-only status differ
Benefits
Thymulin side effects
Thymulin has only limited human data, so the list below is incomplete and its side-effect profile is not well established.
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. FDA's compounding lists show 503A Category 3: Nominated without adequate support.
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
Related research, comparisons & guides
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Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Nov 7, 2026 · Version 2
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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