Is Thymulin approved as a medicine, and where?

No. Thymulin is not an approved medicine anywhere. It is handled as a research chemical, with only limited or early-stage human data.

What is Thymulin studied for?

Thymulin is most often discussed in the context of peptideguide source catalog — verification pending. Being studied for an area does not mean it is proven or approved for it.

Does Thymulin have human clinical trials?

Only to a limited extent. A small number of early-stage human studies exist, but the evidence is preliminary and Thymulin is not approved.

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Immune & Thymic

Thymulin

Thymuline; Serum Thymic Factor (FTS-Zn); FTS (facteur thymique sérique); Zn-FTS; Nonathymulin

4 min read · Updated October 19, 2026 · 19 references

Curated by PeptideInfo Wikilast reviewed October 19, 2026how we verify

Explored forPeptideGuide source catalog — verification pending

In brief · TL;DR

Limited/early human data — not approved

Zinc-dependent thymic nonapeptide (FTS + zinc). Human trials from 1982–1989 were small and mixed: positive in two rheumatoid arthritis trials by the discovering group, negative in a 40-patient MS pilot. Not approved; no clinical development identified after 1989. Serum thymulin is also used as a zinc-status biomarker, which is not evidence for thymulin as a treatment.

Evidence: Only small/early human studies; not approved.

Endogenous thymic nonapeptide (pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn) that is active only as a 1:1 complex with zinc
Human treatment studies date from 1982–1989: small, mixed results and no replication since
Two small rheumatoid arthritis trials were positive; a 40-patient multiple sclerosis pilot found no effect
No approval and no clinical development identified after 1989
Not the same as thymalin, thymosin alpha-1, thymosin beta-4, thymopentin or thymogen

↓ Read the full referenced entry below

Thymulin is an endogenous nine-amino-acid peptide from the thymic epithelium that is biologically active only when bound to zinc. Human treatment data are small and old (1982–1989): a three-patient case series, two placebo-controlled rheumatoid arthritis trials with positive results and a negative multiple sclerosis pilot. No modern clinical trial and no approval were identified; most later research is in animals and cells.

Body & signals →

No receptor relationship mapped here yet. This does not mean the molecule has no biological effects.

Review pending

Contents8

Section 1 of 8What is thymulin?

What is thymulin?

Thymulin is a hormone-like peptide made by the epithelial cells of the thymus. The peptide itself was first isolated as "serum thymic factor" (FTS) and sequenced in 1977 (Dardenne 1977; Pléau 1977). In 1982 the same Paris group showed that FTS is biologically active only when bound to zinc in a 1:1 complex, and named that active complex thymulin (Dardenne 1982). A synthetic version tested in clinical trials in France in the 1980s was called nonathymulin.

Small, old human data — not approved

The human treatment studies are from 1982–1989, small, mostly from the group that discovered the molecule, and not replicated since. No approval and no modern clinical trial were identified.

Section 2 of 8Identity

Identity

Property	Value
Sequence	pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn (nonapeptide)
Active form	1:1 complex with zinc; FTS without zinc is inactive (Dardenne 1982)
PubChem	CID 71300623; C33H54N12O15; 858.9 g/mol — the zinc-free peptide
Other names	FTS (facteur thymique sérique), serum thymic factor, FTS-Zn, nonathymulin

Thymulin is a different substance from thymalin (a Russian thymus-extract preparation), thymosin alpha-1, thymosin beta-4, thymopentin, thymogen and thymic humoral factor. Vendor products rarely state whether zinc is included, and without zinc the peptide is inactive.

Section 3 of 8Human treatment studies (1982–1989)

Human treatment studies (1982–1989)

Immunodeficiency case series (Bordigoni 1982): an uncontrolled report of three children (two with ataxia telangiectasia, one with common variable immunodeficiency). Cell-mediated immune tests and IgA improved, and the effect faded when treatment was paused.
Rheumatoid arthritis (Amor 1987; preceded by a 1984 letter): two randomised, double-blind, placebo-controlled trials. In the best arm, global improvement was 56% versus 17% with placebo (p<0.02). Side effects were minimal, and no clear immunological changes were found. The discoverers of the molecule were co-authors.
Multiple sclerosis (Roullet 1989): a randomised, double-blind pilot in 40 patients treated for six months found no effect and no significant side effects.

No replication after 1989, no modern trial and no human pharmacokinetic study were identified. Development of nonathymulin did not continue according to the published literature.

Section 4 of 8Thymulin as a zinc biomarker

Thymulin as a zinc biomarker

Serum thymulin falls in mild zinc deficiency and normalises with zinc supplementation (Prasad 1988), and it has been measured in malnutrition (Wade 1988) and Crohn's disease (Brignola 1993). Thymulin levels also fall with age. These studies use thymulin as a measurement of zinc status; they are not evidence that giving thymulin works as a treatment.

Section 5 of 8Animal and cell research

Animal and cell research

Thymulin has been studied for T-cell development (reviewed by Bach 1989), neuroendocrine effects (Goya 2004) and gene therapy in thymus-deficiency models (Reggiani 2006). A 2026 mouse study reported that thymulin dampened age-related myeloid inflammation and enhanced anti-PD-L1 treatment (Kanemaru 2026). Effects on pain run in both directions: low doses caused hyperalgesia in rats (Safieh-Garabedian 1997), while high doses reduced endotoxin-induced hyperalgesia (Safieh-Garabedian 1996).

Research-integrity note: a co-author of the 1996 hyperalgesia study, J.J. Haddad, later published single-author thymulin papers that have been removed from the literature. A 2009 Neuroscience paper on thymulin and NF-κB in the hippocampus was retracted in 2010 (PMID 19782726 (opens in a new tab); Crossref/Retraction Watch record for DOI 10.1016/j.neuroscience.2009.09.056 (opens in a new tab)), and a 2009 Cell Immunology paper on a thymulin analogue is listed as withdrawn (PMID 19906366 (opens in a new tab)). Neither is used as support on this page. The 1996 study itself is not retracted, but thymulin anti-inflammatory claims that rest on Haddad's later work should not be treated as established. Data on the related analogue PAT are about a different molecule and are not attributed to thymulin here.

Section 6 of 8Claims vs evidence

Claims vs evidence

Claim	Status	Basis
Endogenous zinc-dependent thymic nonapeptide	Supported	Pléau 1977; Dardenne 1982
Regulates T-cell differentiation	Supported in vitro/animals; weak in humans	Bach 1989
Boosts immunity in humans	Weak	Case series of three (Bordigoni 1982)
Anti-inflammatory	Supported in animals/cells; weak in humans	Kanemaru 2026; RA trials without clear immunological changes
Effective in rheumatoid arthritis	Weak	Two small 1987 trials, not replicated
Effective in multiple sclerosis	Not supported	Roullet 1989 negative
No significant side effects	Weak	Small 1980s trials; low-dose hyperalgesia in rats
Anti-ageing or thymus rejuvenation	No human evidence	Animal data and correlations only

Section 7 of 8Regulatory status

Regulatory status

No approval was identified (FDA, EMA or national), and no interventional thymulin trial is registered on ClinicalTrials.gov. Nonathymulin was tested in France in the 1980s; French national registers were not searched, so this page states only that no approval was identified. This page makes no statement about anti-doping status.

Section 8 of 8What this page intentionally omits

What this page intentionally omits

No trial doses or weekly schedules are reproduced, and thymulin is not presented as a general immune booster or anti-ageing treatment.

References19

References

1.
Dardenne et al. 1977 — isolation of serum thymic factor (J Biol Chem) source
2.
Pléau et al. 1977 — amino-acid sequence of serum thymic factor (J Biol Chem) source
3.
Dardenne et al. 1982 — zinc is required for biological activity; the active complex named thymulin (PNAS) source
4.
Dardenne et al. 1985 — zinc-dependent epitope source
5.
PubChem Compound Summary: CID 71300623 (zinc-free peptide) source
6.
Bach 1989 — review: a zinc-dependent thymic hormone source
7.
Reggiani et al. 2014 — review of physiology and therapeutic potential (Curr Pharm Des) source
8.
Bordigoni et al. 1982 — case series in three children with immunodeficiency (Lancet) source
9.
Amor et al. 1984 — letter on rheumatoid arthritis (Arthritis Rheum) source
10.
Amor et al. 1987 — two randomised placebo-controlled trials in rheumatoid arthritis (Ann Rheum Dis) source
11.
Roullet et al. 1989 — randomised double-blind pilot in multiple sclerosis (Acta Neurol Scand) source
12.
Prasad et al. 1988 — serum thymulin in mild zinc deficiency (J Clin Invest) source
13.
Wade et al. 1988 — thymulin in malnutrition source
14.
Brignola et al. 1993 — Crohn's disease and zinc supplementation source
15.
Kanemaru et al. 2026 — age-related myeloid inflammation in mice (Nat Commun) source
16.
Safieh-Garabedian et al. 1996 — endotoxin-induced hyperalgesia in rats source
17.
Safieh-Garabedian et al. 1997 — low-dose hyperalgesia in rats source
18.
Reggiani et al. 2006 — gene therapy in thymus-deficiency models source
19.
Goya et al. 2004 — review of neuroendocrine effects source

Frequently asked questions4

Frequently asked questions

What is Thymulin?: Thymulin is an endogenous nine-amino-acid peptide from the thymic epithelium that is biologically active only when bound to zinc. Human treatment data are small and old (1982–1989): a three-patient case series, two placebo-controlled rheumatoid arthritis trials with positive results and a negative multiple sclerosis pilot. No modern clinical trial and no approval were identified; most later research is in animals and cells.
Is Thymulin approved as a medicine, and where?: No. Thymulin is not an approved medicine anywhere. It is handled as a research chemical, with only limited or early-stage human data.
What is Thymulin studied for?: Thymulin is most often discussed in the context of peptideguide source catalog — verification pending. Being studied for an area does not mean it is proven or approved for it.
Does Thymulin have human clinical trials?: Only to a limited extent. A small number of early-stage human studies exist, but the evidence is preliminary and Thymulin is not approved.

Educational disclaimer. This article summarizes published research for informational purposes and is not medical advice. Thymulin is a research chemical not approved for human use. Consult a qualified healthcare professional before making health decisions.

References

Frequently asked questions

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