Peptide LibraryTuftsin
Tuftsin is an endogenous immunostimulatory tetrapeptide in the Immune Modulator class. Tuftsin is released by enzymatic cleavage of the IgG heavy chain and binds receptors on neutrophils, monocytes and macrophages, where it has been reported to stimulate phagocytosis, chemotaxis and antigen presentation.
For research use only.
Key Facts
- CAS
- —
- Molecular Weight (MW)
- 500.6 g/mol
- Half-life
- —
- FDA status
- Not Approved
- Evidence level
- Preclinical 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
Research summary
Naturally occurring tetrapeptide derived from the Fc region of immunoglobulin G, studied for effects on phagocytes. It is the structural parent of Selank. Not FDA-approved.
Research evidence
- Regulatory review (FDA label)None in reviewed sources
- Controlled human trialsNone in reviewed sources
- Early or uncontrolled human studiesNone in reviewed sources
- Lab & animal studies2 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 Tuftsin 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.
Tuftsin dosage: no established human dose
Tuftsin has no established human dosage. It is a four-amino-acid peptide (Thr-Lys-Pro-Arg) released from antibodies, and no published or registered study has given it to people as a treatment. Human papers on tuftsin measure the body's own levels, for example after removal of the spleen, or test it on blood cells in the lab. It is not FDA-approved.
No established human dosage.
Human clinical evidence: None identified.
Preclinical research: Tuftsin is cut from the Fc part of immunoglobulin G and acts on phagocytic cells, notably macrophages, where lab and animal studies report more phagocytosis, movement and killing activity. Much recent work uses it as a targeting tag in nanoparticles or drug conjugates, or as tuftsin-phosphorylcholine in animal models of autoimmune disease, which are different products. No human dose has been studied.
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 | Not established in humans |
| Evidence level | Preclinical Evidence |
| Last reviewed | 2026-11-07 |
Preclinical and analog research
Not human dosing evidence. Listed for completeness and never extrapolated to a human dose.
| Study / context | Population | Dose | Route | Frequency | Duration | Outcome studied | Source |
|---|---|---|---|---|---|---|---|
| Review of tuftsin chemistry, biology and clinical potential (1989)Preclinical · Narrative review | Not applicable (review of laboratory and animal work) | No dose stated in the indexed abstract | — | — | — | Describes stimulation of phagocytosis, movement and killing activity of macrophages, and low toxicity | Tuftsin: its chemistry, biology, and clinical potential. Crit Rev Biochem Mol Biol. 1989. |
| Tuftsin built into a peptide nanoparticle, septic mice (2025)Preclinical · Animal study of a tuftsin-containing nanoparticle, not tuftsin alone | Mice with sepsis and secondary lung infection | No dose stated in the indexed abstract | — | — | — | Better survival and macrophage function reported with the nanoparticle | FcγR-targeted tuftsin clusters rejuvenate macrophages in preclinical sepsis-associated secondary infection. Sci Transl Med. 2025. |
Where sources disagree
- Selank is a tuftsin analog with its own Russian clinical studies, but those studies do not state a dose in their indexed records and would not give a dose for tuftsin itself.
- Studies of tuftsin conjugates, nanoparticles and tuftsin-phosphorylcholine test different molecules. Their results do not transfer to plain tuftsin.
Sequence & molecular data
| Amino acid sequence | Thr-Lys-Pro-Arg |
|---|---|
| Molecular formula | C21H40N8O6 |
| Molecular weight | 500.6 g/mol |
| PubChem CID | 156080 |
| FDA UNII | QF5336J16C |
| ChEMBL | CHEMBL4563222 |
Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.
Science
Mechanism of Action
Tuftsin is released by enzymatic cleavage of the IgG heavy chain and binds receptors on neutrophils, monocytes and macrophages, where it has been reported to stimulate phagocytosis, chemotaxis and antigen presentation. Its very short plasma half-life is the main obstacle to therapeutic use and the reason stabilised analogs such as Selank were developed.
Studies
- Helminth derivative tuftsin-phopshorylcholine to treat autoimmunity
- Tuftsin phosphorylcholine-a novel compound harnessing helminths to fight autoimmunity
- Tuftsin - Properties and Analogs
- FcγR-targeted tuftsin clusters rejuvenate macrophages in preclinical sepsis-associated secondary infection
- The P2X7-Mediated Mitochondrial ROS as an Emerging Core Target of Tuftsin Nanoparticles in Severe Acute Pancreatitis Therapy via Regulating Mitophagy
Research statistics
623 PubMed publications · 4.8% 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
Tuftsin is not an FDA-approved product. It is sold for laboratory research and has no approved medical use.
| FDA status | Not Approved |
|---|---|
| Research status | Research-only compound; no approval pathway listed |
| Availability | Research-Only |
| WADA (sport) | Unknown / Not Listed |
| Library classification | Research-Only |
How FDA approval, compounding and research-only status differ
Benefits
—
Tuftsin side effects
No side effects listed yet for this entry.
Storage & stability
This compound is not supplied as a powder to be mixed, so the freeze-dried powder and reconstitution handling described for research peptides does not apply. Storage conditions are product-specific: follow the label or packaging of the product itself.
Tuftsin: frequently asked questions
What is Tuftsin?
Naturally occurring tetrapeptide derived from the Fc region of immunoglobulin G, studied for effects on phagocytes. It is the structural parent of Selank. Not FDA-approved.
How does Tuftsin work?
Tuftsin is released by enzymatic cleavage of the IgG heavy chain and binds receptors on neutrophils, monocytes and macrophages, where it has been reported to stimulate phagocytosis, chemotaxis and antigen presentation. Its very short plasma half-life is the main obstacle to therapeutic use and the reason stabilised analogs such as Selank were developed.
Is Tuftsin FDA approved?
No. Tuftsin 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 Tuftsin?
Tuftsin has the sequence Thr-Lys-Pro-Arg, giving a chain of 4 amino acids. Its molecular formula is C21H40N8O6.
What peptides are similar to Tuftsin?
Compounds most often compared with Tuftsin include Selank, N-Acetyl Selank Amidate, Semax and Noopept. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.
References
- Helminth derivative tuftsin-phopshorylcholine to treat autoimmunity — Autoimmun Rev, 2024External reference
- Tuftsin phosphorylcholine-a novel compound harnessing helminths to fight autoimmunity — Immunol Res, 2018External reference
- Tuftsin - Properties and Analogs — Curr Med Chem, 2017External reference
- FcγR-targeted tuftsin clusters rejuvenate macrophages in preclinical sepsis-associated secondary infection — Sci Transl Med, 2025External reference
- The P2X7-Mediated Mitochondrial ROS as an Emerging Core Target of Tuftsin Nanoparticles in Severe Acute Pancreatitis Therapy via Regulating Mitophagy — ACS Appl Mater Interfaces, 2025External reference
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Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Nov 7, 2026 · Version 2
This Tuftsin 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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