Independent · non-commercial · publishes on a quarterly cycle|Current cycle 2026 Q3
Compound Evidence InstituteEvidence synthesis · established 2023Graded assessments of compounds, trials, methods and supply
Document set current to 30 July 2026
Compound monograph · Immune modulators

Thymalin — compound monograph

Thymic peptide extract of undefined composition. Approved. The Institute assesses 2 outcomes for this compound and grades the strongest at very low certainty.

Document identifier
CEI-MN-041
Series
Compound monograph
Version
4.1
Published
15 Oct 2025
Last reviewed
15 Jul 2026
Next review
15 Jul 2028
Identifier
10.71829/cei.mono.41
Certainty
Very low
Cycle
2025 Q4

§1Identification and status

§1.1Nomenclature

Preferred name
Thymalin
Compound class
Thymic peptide extract of undefined composition
Assessment series
Immune modulators
Synonyms and codes
thymalin · thymus polypeptide extract · Vilon (related dipeptide preparation)
Route as evaluated
Intramuscular in the approved Russian presentation

§1.2Chemistry

Chemical identifiers are reproduced where they are public. Where a structure has not been published the monograph records not disclosed rather than constructing one.[1]

CAS registry number
not applicable (extract)
Molecular formula
not applicable
Average mass
a mixture of peptides in the approximate range 1000–10,000 Da
Monoisotopic mass
not applicable
ATC classification
not assigned

§1.3Sequence and structural notes

Not a defined single substance — a fractionated extract of calf thymus

Thymalin is an extract, not a molecule. It has no sequence, no molecular formula and no single molecular mass. The Institute includes a monograph specifically to record that a compound of undefined composition cannot be characterised by the analytical framework applied to synthetic peptides, and that certificates presenting an HPLC purity percentage for an extract are describing something that has no meaning.

§1.4Assessment status

The Institute assesses Thymalin across 2 indications and grades the strongest of them at very low certainty. Holds a marketing authorisation for at least one indication in at least one jurisdiction.

Distribution of certainty ratingsShare of assessed outcomes at each certainty level.2assessed outcomes
HighModerateLowVery low
Figure 1. Distribution of certainty ratings across the 2 outcomes the Institute assesses for Thymalin. A rating attaches to a specific population, comparator and outcome and does not transfer between them.

Table 1. Assessed outcomes for Thymalin, ordered by certainty. Each row links to the per-indication evidence extract.

IndicationEffect as recordedCertaintyTrials
Biological ageing and healthspan endpointsNo assessable evidence identifiedVery low0
Immune modulation and adjunctive immunotherapyRussian clinical reports describe immunological and clinical effects across a wide range of conditionsVery low1
Effects are reproduced as the contributing trials reported them. Where a confidence interval is held it appears on the per-indication extract rather than in this summary table.

References cited on this page

References are numbered in order of first citation in this document. Each superscript in the text links to its entry below.

  1. International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. ICH Q6B Specifications: Test Procedures and Acceptance Criteria for Biotechnological/Biological Products. ICH Harmonised Tripartite Guideline 1999;Step 4 version. identifier not held by the Institute

Identifiers are reproduced only where the Institute holds them. Where a digital object identifier or PubMed identifier is not shown, the Institute has recorded the journal and year and has not constructed an identifier.

Nothing published by the Institute is medical advice, a diagnosis, a prescription, a treatment recommendation or a purchasing recommendation. Compounds supplied for research use are not approved for human or veterinary use in any jurisdiction, and a favourable analytical assessment of a supplier is not a statement that any product is safe or effective. The Institute publishes certainty ratings and never recommendations. No telephone number, messaging handle or ordering channel appears anywhere on this site.