Thymic polypeptide extract (immunomodulator research) Limited Human Data

Thymalin

Also Known As: Thymalinum

Thymalin is a polypeptide extract of calf thymus developed by Vladimir Khavinson and colleagues at the Saint-Petersburg Institute of Bioregulation and Gerontology. It is NOT a single defined peptide but a complex mixture of low-molecular-weight thymic polypeptides. Thymalin must be distinguished from Thymosin α1 (a synthetic 28-residue peptide) and from Thymulin. Limited human data — the published evidence base is predominantly Russian-language and from the Khavinson lineage. Research use only.

Thymalin – peptide vial product image

Identity & Chemistry

Amino Acid Sequence
Thymalin is a polypeptide extract of calf-thymus origin (Khavinson / Saint-Petersburg Institute of Bioregulation and Gerontology). It is not a single defined sequence but a complex mixture of low-molecular-weight thymic polypeptides. Distinct from Thymosin α1 (a synthetic 28-residue peptide) and from Thymulin.
Molecular Formula
Mixture — no single molecular formula
Molecular Weight
Approximate range 1,000–10,000 Da (low-molecular-weight thymic polypeptide fraction)
IUPAC Name
Not applicable — polypeptide mixture, not a single chemical entity

Mechanism of Action

Studies report immunomodulatory effects with restoration of T-cell maturation and modulation of cytokine responses. Observed in research settings.

Because thymalin is a mixture, no single receptor or single signalling pathway can be identified as the mechanism of action. The Khavinson group reports immunomodulatory and geroprotective effects in animal and small human studies, predominantly in Russian-language literature. Mechanism statements are intentionally hedged.

Molecular Targets

  • T-lymphocyte maturation (complex mixture — discrete molecular targets not fully characterised)
  • Cytokine networks (reported)

Signaling Pathways

  • Thymopoiesis / T-cell differentiation
  • General immunomodulatory signalling

Research Applications

The published evidence base consists predominantly of Russian-language Khavinson-school studies with limited independent international replication.

Geriatric immune function — small human observational studies

observational

Studies from the Khavinson lineage report improved T-cell parameters and reduced infection rates in elderly patients; independent replication is limited.

— Khavinson VK 2002, Neuroendocrinol Lett 23 Suppl 3:11-144

Clinical Status

Regulatory Status
Thymalin is registered in Russia as an immunomodulator (historical Soviet / Russian pharmaceutical register). It is NOT approved by the FDA, EMA, MHRA or any other Western regulator.
Sponsor
Saint-Petersburg Institute of Bioregulation and Gerontology (Khavinson lineage)

Safety Profile

Observed in research settings

Limited human data. The Russian-language literature describes thymalin as well tolerated; Western pharmacovigilance data do not exist. Observed in research settings.

Adverse Events Reported in Studies

  • Injection-site reactions (reported)
  • Rare: allergic reactions (reported)

References

  1. Khavinson VK Peptides and Ageing Neuroendocrinology Letters 2002;23 Suppl 3:11-144. 2002 .

    PMID: 12374094 View Source

  2. Anisimov VN, Khavinson VKh Peptide bioregulation of aging: results and prospects Biogerontology 2010;11(2):139-149. 2010 .

    DOI: 10.1007/s10522-009-9249-8 PMID: 19690988 View Source

  3. Kuznik BI, Linkova NS, Tarnovskaya SI, Khavinson VKh Peptide regulation of gene expression: a systematic review Molekuliarnaia Biologiia (Moscow) 2014;48(3):373-383. 2014 .

    PMID: 25831887 View Source

Frequently Asked Questions

Is thymalin the same as thymosin α1?
No. Thymosin α1 is a synthetic 28-residue peptide with a defined sequence. Thymalin is a low-molecular-weight polypeptide fraction extracted from calf thymus — a mixture, not a single peptide.
Is thymalin approved in the EU or US?
No. Thymalin is registered only in Russia. It is not approved by the FDA, EMA or any other Western regulatory agency.

Related Peptides

Thymosin Alpha-1

≥98%

Thymic peptide hormone analogue / immune modulator (slug: immune-other; pleiotropic TLR2/TLR9-mediated effect rather than a classical single-receptor agonist)

Synthetic 28-amino-acid N-acetylated thymic peptide (thymalfasin / Zadaxin); pleiotropic TLR2/TLR9-mediated immune modulator — approved as Zadaxin in 35+ countries (Italy, China, Vietnam, Mexico and others) for chronic hepatitis B and as a vaccine adjuvant in immunocompromised populations, but NOT FDA-approved in the United States — only orphan-drug designations exist there.

View Details

Epitalon

≥98%

Synthetic Pineal Tetrapeptide (AEDG, Bioregulator Class — Mitochondrial / Longevity Research)

Synthetic tetrapeptide Ala-Glu-Asp-Gly (AEDG) modeled on the active fraction of the bovine pineal extract Epithalamin. In vitro telomerase findings were independently replicated in 2025; human data are limited to small single-center open-label observational studies from one research group. Research use only; not approved by FDA or EMA.

View Details

BPC-157

≥98%

Synthetic cytoprotective pentadecapeptide (tissue-repair / healing research compound)

Synthetic 15-amino-acid pentadecapeptide (PL-14736) derived from a fragment of a 60-aa protein in human gastric juice. Proposed cytoprotective and angiogenic activity is largely inferred from preclinical rodent and in-vitro data; not approved by any regulator and intended for research use only.

View Details