RESEARCH MONOGRAPH · KDC-MN-130

Thymopentin

May 9, 2026 Kodiac biolabs Research Revised May 30, 2026 2 min read

Our opinion on this compound

66/100

A defined pentapeptide with actual approval history in Europe and real T-cell pharmacology

Thymopentin (TP-5) is Arg-Lys-Asp-Val-Tyr, residues 32 to 36 of thymopoietin. Goldstein's group at NYU isolated thymopoietin in the 1970s and showed that this pentapeptide retained most of the bioactivity of the parent 49-residue protein. It binds an unidentified receptor on T-cell precursors, induces differentiation markers (CD3, CD4, CD8 expression), and modulates T-helper to T-suppressor ratios.

Whats different about Thymopentin versus the Russian thymic peptides is that it actually made it through Western drug development. It was approved in Italy and a few other European countries as Timunox for chronic hepatitis B and as adjunct immunomodulation in various contexts. The clinical files are real even if the indications never really took off commercially, mostly because pegylated interferon and then direct-acting antivirals leapfrogged the immunomodulator angle.

What we like: defined sequence, real pharmacology, actual regulatory history. The T-cell maturation effects have been replicated by multiple independent groups, which puts it ahead of most thymic peptides on the reproducibility axis. And the parent-protein-to-active-fragment story is satisfying biology.

What we dont like: the receptor is still unidentified. Thats a real gap. Without a defined receptor you cant do clean structure-activity work or selective pharmacology. The half-life is also brutally short (a few minutes in plasma), which is why the clinical dosing was three times weekly subcutaneous, which made adoption operationally annoying.

Mechanism-wise: defined effects on lymphocyte differentiation, downstream NFAT and IL-2 modulation, but the upstream binding partner is the missing piece. People have speculated for decades.

Sourcing: short defined synthetic peptide, easy to make, HPLC purity is usually fine from reputable vendors. The clinical-grade material from the original Italian manufacturers had specific stability formulation considerations; research-grade is more forgiving.

If you care about immunopeptide research with actual clinical translation, Thymopentin is probably the most evidence-anchored compound in the thymic peptide bucket. Underrated relative to its data quality, honestly.

Evidence: 65
Mechanism: 60
Reliability: 70
Safety: 80
Sourcing: 75
Value: 65
Signal: 55
Staying power: 60

Plain-language summary Intrigue 50 / 100

Thymopentin is a 5-amino-acid synthetic peptide representing the active region of thymopoietin. Used historically for psoriasis and immune modulation. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Synthetic pentapeptide of thymopoietin

A synthetic pentapeptide fragment (residues 32-36) of thymopoietin marketed in Europe and Asia for immunomodulation in chronic infections and autoimmune disease.

Abstract

Thymopentin (Timunox, TP-5; Arg-Lys-Asp-Val-Tyr; CAS 69558-55-0; molecular weight 679.78) is a synthetic pentapeptide corresponding to residues 32-36 of thymopoietin, a thymic hormone. The fragment retains the immunomodulatory activity of full-length thymopoietin. The compound is approved in Italy and several Asian countries for primary immunodeficiency, hepatitis B, atopic dermatitis adjunct, and autoimmune disease support. Mechanism includes T-cell maturation, NK cell modulation, and cytokine balance effects. Administered subcutaneously. Reported research dose ranges in the literature use milligram quantities subcutaneously.

Mechanism of action

Thymopoietin 32-36 fragment; T-cell maturation, NK and cytokine modulation.

Reported research dose ranges

Reported research dose ranges in the literature describe milligram quantities administered subcutaneously.

References

Goldstein G. Thymopentin. Methods Enzymol 1985.

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KDC-MN-130

The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

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Thymopentin

Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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