Thymopentin

also known as: TP-5, TP5, Timunox, Thymopoietin 32-36

A synthetic pentapeptide fragment of thymopoietin — historically marketed as Timunox for immunodeficiency, now primarily used in research and limited European clinical practice.

A pentapeptide (Arg-Lys-Asp-Val-Tyr) corresponding to the biologically active site of thymopoietin, originally developed by Ortho Pharmaceuticals and marketed as Timunox for immunodeficiency conditions in several European countries.

Mechanism of action

Induces T-cell differentiation from immature precursors, modulates T-helper and T-suppressor activity, and enhances NK cell cytotoxicity. Despite ultra-short plasma half-life, signaling effects on T-cell lineage commitment persist for days. Used primarily in secondary immunodeficiency states.

Primary uses

Secondary immunodeficiency (European approval)
Rheumatoid arthritis (European approval)
Chronic hepatitis adjunct
Research on thymic peptide signaling

Typical dosing

50 mg 3 times weekly (subcutaneous)

European clinical dosing: 50 mg SC three times weekly.

Regulatory status

Approved in several European countries (Italy, Germany) as Timunox for immunodeficiency states, rheumatoid arthritis, and chronic hepatitis. Not FDA-approved.

References

[pubmed] Goldstein G, et al. "A synthetic pentapeptide with biological activity characteristic of the thymic hormone thymopoietin." Science, 1979;204:1309-1310.
[pubmed] Malaise MG, et al. "Treatment of active rheumatoid arthritis with slow intravenous injections of thymopentin. A double-blind placebo-controlled randomized study." Lancet, 1987;1:832-836.

Related peptides

Thymosin α1

The most clinically studied thymic peptide — approved in 35+ countries as Zadaxin for hepatitis B and C, with 30+ RCTs across more than 11,000 subjects. Not FDA-approved despite extensive global use.

Thymulin

A zinc-dependent thymic peptide — biologically active only when zinc-saturated, making serum thymulin activity a functional readout of zinc status.

Thymosin β4

The natural 44-amino-acid parent of the TB-500 research peptide — in clinical trials (as RGN-259/Lacripep) for dry eye disease, corneal wounds, and dermal healing.

Disclaimer

This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.