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Healing & repairPeptideEvidence C3 cited

Thymalin

Thymic Peptide Bioregulator

aka Thymalin extract · thymic factor · thymus extract

A thymus-derived peptide bioregulator researched for T-cell modulation and immune system restoration.

Half-life
2 h
estimated
Tmax
1 h
Route
Subcutaneous injection

Sequence

Read this before quoting the sequence
Thymalin is not a single defined molecule and therefore has no sequence. Indexed sources describe it as 'a polypeptide complex isolated from the thymus' (calf) and 'an immunomodulatory drug containing a polypeptide extract of thymus', with the dipeptides KE (Lys-Glu) and EW (Glu-Trp) identified by the originating group as its active substances. Because it is an undefined extract, no single molecular formula, molecular weight, CAS number or PubChem CID can legitimately be assigned. Note that PubChem lists 'Thymalin' as a synonym on the Nonathymulin record (CID 3085284, the thymulin nonapeptide); that is an indexing conflation - thymalin and thymulin are different things.
Source ↗

Mechanism of action

Thymalin is a peptide bioregulator derived from the thymus gland, which plays a role in modulating the immune system. It is thought to enhance the activity of T-cells and other immune cells, thereby improving immune response. Thymalin may also influence the production of cytokines, which are crucial for cell signaling in immune responses. Additionally, it is believed to have antioxidant properties that protect cells from oxidative stress.

What the evidence actually shows

Grade C

There are limited human trials on Thymalin, with most studies conducted in Russia. These studies suggest potential benefits in immune modulation and anti-aging, but the sample sizes are small and methodologies vary. More rigorous, large-scale trials are needed to confirm these effects.

Regulatory status

Status
Not approved by FDA or EMA (no Drugs@FDA record, no DailyMed SPL). Described in indexed literature as a registered immunomodulatory drug used clinically in Russia; the Russian registration certificate itself was not retrieved.
Clinical stage
No ClinicalTrials.gov-registered trials found. Human data consist of open-label and non-randomised reports from the St Petersburg Institute of Bioregulation and Gerontology group.
WADA
Not named on the WADA 2026 Prohibited List.
UK
research_compound

In the UK, Thymalin is considered a research compound and is not approved for medical use by the MHRA.

Source ↗

Pharmacokinetics

Half-life
2 h
Tmax
1 h
Absorption
subcutaneous
Elimination
renal
Washout
2 days
Low-confidence pharmacokinetics
These figures are recorded as estimated rather than measured in a published PK study. Treat them as an order of magnitude. Anything downstream of them — accumulation, steady state, washout — inherits that uncertainty.

Dosing — what backs each figure

Thymalin is a bovine thymus polypeptide extract (not a synthetic peptide) registered in Russia; the one retrievable indexed human dosing regimen is 10 mg intramuscularly once daily for 5 days as add-on therapy in moderate-to-severe COVID-19. The widely cited geroprotection work (Khavinson & Morozov, 266 elderly subjects over 6-8 years, PMID 14523363) reports courses given over 2-3 years but states no dose in the retrievable record.

ClinicalApproved labelling or a published human trial

Handling and storage

No compound-specific stability data exists
No FDA or EMA label exists (absent from Drugs@FDA and DailyMed). Thymalin is a Russian-registered immunomodulatory preparation; its Russian package insert was not retrievable from a source acceptable under this project's rules, and no peer-reviewed stability data were located. Ported storage text ('-20C ~24 months lyophilised; 2-8C ~4 weeks reconstituted') is generic peptide-handling boilerplate that was applied identically across many compounds in this dataset. It is not sourced to this compound. General peptide handling still applies — reconstitute gently, keep it cold, keep it dark — but any specific figure you see quoted for this compound elsewhere is someone's assumption, not a measurement.
→ Reconstitution walkthrough→ Reconstitution calculator

Safety

Commonly reported
  • ·Injection site reactions
  • ·Mild headache
Rarely reported
  • ·Allergic reactions
  • ·Autoimmune flare-ups
Contraindications
  • ·Pregnancy
  • ·Breastfeeding
  • ·"Known hypersensitivity to thymic peptides"
Drug interactions
  • ·Immunosuppressants: May reduce the effectiveness of Thymalin by opposing its immune-enhancing effects.

Reported combinations

Reported as synergistic
  • ·Thymosin Alpha-1
  • ·Vitamin D
Reported as antagonistic
  • ·Corticosteroids

Combination claims in this dataset are largely unsourced and should be treated as folk knowledge until a citation appears beside them.

References (3)

Data provenance

Chemistry and citations on this page were checked against primary sources on 2026-08-14. Values that could not be verified were left blank rather than filled with a plausible guess.

Could not verify
sequence, molecularFormula, molecularWeight, casNumber, pubchemCid, storage.lyophilized, storage.reconstituted, storage.lightSensitive, reconstitution.solvent

Research use only
This profile is educational reference material. It is not medical advice, not a prescription, and not an endorsement of self-administration. Compounds discussed here are research chemicals and most are not approved for human therapeutic use.

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