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IMMUNEPEPTIDE PROFILE

Thymopoietin

Also known as Thymopoietin II, Thymopoietin III, TMPO, Lamina-associated polypeptide 2

Thymopoietin is a 49-amino acid thymic hormone produced by thymic epithelial cells, existing as isoforms (Thymopoietin I, II, and III). It plays a central role in T-lymphocyte differentiation and maturation, helping to establish and maintain cell-mediated immunity. Research has focused on its immunomodulatory properties in aging, immunodeficiency states, and as the parent protein from which the active pentapeptide Thymopentin (TP-5) was derived.

Last updated April 10, 2026

TL;DR

Quick summary

Thymopoietin is a 49-amino acid thymic hormone that drives T-lymphocyte differentiation and maturation. It is the parent protein of the clinically active pentapeptide Thymopentin (TP-5) and serves as a historical benchmark in thymic peptide immunology research.

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Overview

Thymopoietin is a 49-amino acid thymic hormone produced by thymic epithelial cells, existing as isoforms (Thymopoietin I, II, and III). It plays a central role in T-lymphocyte differentiation and maturation, helping to establish and maintain cell-mediated immunity. Research has focused on its immunomodulatory properties in aging, immunodeficiency states, and as the parent protein from which the active pentapeptide Thymopentin (TP-5) was derived.

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Mechanism of action

Thymopoietin acts on lymphoid progenitor cells to induce T-cell lineage commitment and differentiation markers. It suppresses neuromuscular transmission (early research linked it to myasthenia gravis) via acetylcholine receptor modulation. Its immunological actions are mediated through the active pentapeptide sequence (residues 32–36, Arg-Lys-Asp-Val-Tyr), which corresponds to Thymopentin. Full-length Thymopoietin is thought to interact with both immune cell receptors and nuclear lamina proteins in its role as a structural component.

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Dosing protocols

PurposeRouteDosageFrequency
immunological researchsubcutaneous110 mgper experimental protocol

Dosing information is for educational purposes only. Consult a qualified healthcare professional before using any peptide.

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Research summary

Thymopoietin research established the concept of thymic hormonal control of T-cell development. Early studies in the 1970s–1980s by Gideon Goldstein's group characterized its structure and immunological activity. Later research led to isolation of the active TP-5 fragment. Interest has extended to Thymopoietin's role as a nuclear lamina protein (LAP2), with implications for progeria-like diseases and DNA repair. Modern immunotherapy research treats Thymopoietin as a historical benchmark for thymic peptide pharmacology.[1][2][3][4]

📄This section cites 4 peer-reviewed sources. View all references →
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Evidence grading

Each claimed benefit is graded by the strength of available evidence. Grades reflect study quality, not effect size.

moderate
Induces T-cell lineage differentiationConsistent 1970s-1980s lymphoid progenitor differentiation studies
strong
Active pharmacophore resides in residues 32-36Structure-activity studies establishing TP-5 fragment retains full activity
moderate
Nuclear lamina structural function (LAP2)Consistent molecular biology studies of LAP2 isoform function
preliminary
Modulates acetylcholine receptor signalingHistorical myasthenia gravis research; mechanism not fully characterized

Strong = multiple RCTs · Moderate = limited trials or observational · Preliminary = animal or in vitro only · Insufficient = anecdotal or no published data

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Side effects

Injection site reactions
Transient immune activation

Side effects vary by individual. This is not an exhaustive list. Report unusual symptoms to a healthcare professional.

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Common stacks

Peptides commonly paired with Thymopoietin for synergistic effects.

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Sourcing & access

Research compound

Thymopoietin is classified as a research compound. Regulatory status varies by jurisdiction. Always verify current legal status and source from vendors providing third-party certificates of analysis (COA).

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Frequently asked questions

Thymopoietin is a 49-amino acid hormone produced by thymic epithelial cells that plays a central role in T-cell differentiation and maturation. It exists as multiple isoforms and is the parent protein from which the active pentapeptide Thymopentin (TP-5) was derived.

Thymopoietin acts on lymphoid progenitor cells to induce T-cell lineage commitment and differentiation markers. Its immunological actions are mediated through the active pentapeptide sequence at residues 32-36 (Arg-Lys-Asp-Val-Tyr). It also modulates acetylcholine receptor signaling and functions as a nuclear lamina protein.

Reported side effects in research settings include injection site reactions and transient immune activation. Full-length Thymopoietin is classified as research-only and is not approved for human clinical use, though its active fragment Thymopentin has been approved in some countries.

Thymopentin (TP-5) is the synthetic pentapeptide corresponding to residues 32-36 of Thymopoietin. This five-amino acid fragment retains the full immunomodulatory activity of the parent protein and has been developed as a clinical immunomodulator approved in Italy and other countries.

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Research references

  1. Thymopoietin: a thymic hormone regulating T-cell differentiationGoldstein G, et al.Nature, 1975PubMed
  2. Thymopoietin receptor signaling and T-lymphocyte maturationAudhya T, Kroon D, et al.Arch Biochem Biophys, 1985PubMed
  3. Clinical applications of thymopoietin and its pentapeptide fragment thymopentinFavalli C, et al.Int J Immunopharmacol, 1995PubMed
  4. Thymopoietin II and antigen-independent induction of T-cell differentiation markersSztein MB, et al.Scand J Immunol, 1998PubMed
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