Thymalin
Also known as: Thymic extract peptide, Thymalinum
Thymalin (also called Thymic extract peptide or Thymalinum) is a thymic polypeptide extract. Thymalin is a preparation of low-molecular-weight peptides extracted from calf thymus rather than a single defined molecule, which is the central fact for interpreting it: no specific sequence, receptor or signalling pathway can be assigned, and batch composition is not standardised as a single-entity drug would be.
For research use only.
Key Facts
- CAS
- —
- Molecular Weight (MW)
- Mixture
- Half-life
- Not established (polypeptide complex)
- FDA status
- Not Approved
- Administration Route
- Intramuscular (ex-US medical use)
- Frequency
- —
- Last updated
- Aug 30, 2026
- Reviewed
- Aug 30, 2026
- Targets
- T-cell maturation (proposed)
Vendor price snapshot
Each vendor counts once, at the median price per mg of its own listings; the typical range is the middle half of vendors. From public vendor listings collected between Dec 2025 and Sep 2026, so confirm the live price on the vendor site. Peptide Library does not sell peptides.
- Vendors listing this peptide
- 13
- Listed offers
- 14
- Median price per mg
- $6.40/mg
- Typical $5.57–$8.13/mg
Research summary
Thymus-derived polypeptide preparation used in some countries as an immunomodulator. Not FDA-approved; composition is an extract, not a single sequence.
Peptide Library's Thymalin profile summarises 5 cited studies listed in the Science section, the compound's regulatory status, and research-protocol parameters reported for it. It is a research reference, not medical advice.
Protocol
- Dosage Range
- Per RU/EU label or research protocol
- Frequency
- —
- Cycle
- —
- Administration Route
- Intramuscular (ex-US medical use)
- Reconstitution Guide
- —
- Timing Notes
- Immunomodulatory thymic preparation; not FDA-approved.
Not yet checked against primary sources
These figures are compiled from earlier reference material. They have not been verified against FDA labelling, registered trials or published literature, no citation is attached to them, and none of them is a recommended dose. Thymalin is queued for dosage evidence review.
Compare reported doses across the whole librarySequence & molecular data
| Molecular formula | Peptide mixture (2–10 kDa fraction) |
|---|---|
| Molecular weight | Mixture |
| Half-life | Not established (polypeptide complex) |
| Appearance | White lyophilized powder for injection (ex-US labels) |
| Formulation | Lyophilized Powder |
Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.
Science
Mechanism of Action
Thymalin is a preparation of low-molecular-weight peptides extracted from calf thymus rather than a single defined molecule, which is the central fact for interpreting it: no specific sequence, receptor or signalling pathway can be assigned, and batch composition is not standardised as a single-entity drug would be. It is described as restoring T-cell differentiation in a manner analogous to endogenous thymic hormones, with reported effects on lymphocyte subsets in ageing and immunodeficient states. It is used clinically in several post-Soviet countries. The supporting evidence is regional and largely uncontrolled, and it is not a monographed active ingredient in the United States.
Origin
Bovine thymic polypeptide preparation.
Targets
Studies
- [Use of thymic peptide thymalin in the complex treatment of therapy-resistant schizophrenia]
- Expression features of T-lymphocytes, B-lymphocytes and macrophages in the post-traumatic regenerate of the mandible rats under conditions of filling a bone defect with hydroxyapatite-containing osteotropic material and thymalin injecting the surrounding soft tissues
- Reparative osteogenesis in mandible in cases of filling a bone defect with hydroxyapatite-containing osteotropic material and injecting the surrounding soft tissues with thymalin: experimental and morphological study
- The Influence of KE and EW Dipeptides in the Composition of the Thymalin Drug on Gene Expression and Protein Synthesis Involved in the Pathogenesis of COVID-19
- [Geroprotective effect of thymalin and epithalamin]
Regulatory & research status
Thymalin is not an FDA-approved product. It is sold for laboratory research and has no approved medical use.
| FDA status | Not Approved |
|---|---|
| Availability | Research-Only |
| WADA (sport) | Unknown / Not Listed |
| Library classification | Research-Only |
Benefits
Thymalin side effects
Side Effects
- Allergic reactions to animal protein
Storage & stability
Lyophilized (freeze-dried) peptide powder is far more stable than the reconstituted solution. Keep sealed vials cold, dry and away from light; long-term storage is typically frozen, with short-term refrigeration for vials in use.
Once reconstituted in bacteriostatic water, keep the solution refrigerated, avoid repeated freeze–thaw cycles and agitation, and label the vial with the reconstitution date and concentration. Discard any solution that turns cloudy or shows particulates.
Degradation rates differ by sequence: peptides containing methionine, cysteine, asparagine or glutamine are more prone to oxidation and deamidation, so shelf life after reconstitution is compound-specific rather than universal.
Read the full guide: how to store peptides before and after reconstitution →
Source: Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575. (PMID 20143256). General guidance for research handling; not product-specific instructions.
Thymalin: frequently asked questions
What is Thymalin?
Thymus-derived polypeptide preparation used in some countries as an immunomodulator. Not FDA-approved; composition is an extract, not a single sequence.
How does Thymalin work?
Thymalin is a preparation of low-molecular-weight peptides extracted from calf thymus rather than a single defined molecule, which is the central fact for interpreting it: no specific sequence, receptor or signalling pathway can be assigned, and batch composition is not standardised as a single-entity drug would be. It is described as restoring T-cell differentiation in a manner analogous to endogenous thymic hormones, with reported effects on lymphocyte subsets in ageing and immunodeficient states.
Is Thymalin FDA approved?
No. Thymalin is not approved by the FDA for any indication and is categorised as research-only. It has not been reviewed for safety or efficacy as a medicine, and published research should be read as investigation rather than established use.
What is the half-life of Thymalin?
Reported half-life for Thymalin is Not established (polypeptide complex). Half-life describes how long the compound persists in circulation, not how long any effect lasts, and published figures vary with route of administration, formulation and the population studied.
What peptides are similar to Thymalin?
Compounds most often compared with Thymalin include Thymosin Alpha-1, Thymogen (Oglufanide), Thymopentin and Thymulin. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.
References
- [Use of thymic peptide thymalin in the complex treatment of therapy-resistant schizophrenia] — Zh Nevropatol Psikhiatr Im S S Korsakova, 1990External reference
- Expression features of T-lymphocytes, B-lymphocytes and macrophages in the post-traumatic regenerate of the mandible rats under conditions of filling a bone defect with hydroxyapatite-containing osteotropic material and thymalin injecting the surrounding soft tissues — Pol Merkur Lekarski, 2024External reference
- Reparative osteogenesis in mandible in cases of filling a bone defect with hydroxyapatite-containing osteotropic material and injecting the surrounding soft tissues with thymalin: experimental and morphological study — Wiad Lek, 2024External reference
- The Influence of KE and EW Dipeptides in the Composition of the Thymalin Drug on Gene Expression and Protein Synthesis Involved in the Pathogenesis of COVID-19 — Int J Mol Sci, 2023External reference
- [Geroprotective effect of thymalin and epithalamin] — Adv Gerontol, 2002External reference
Related research, comparisons & guides
Related peptides
Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Aug 30, 2026 · Version 1
This Thymalin profile is compiled from published literature (5 cited studies linked above), public regulatory records and chemical registries. It describes what research reports; it is not medical advice, and nothing here is a dosing recommendation for humans. Peptide Library does not sell peptides. Editorial policy · How profiles are compiled · Report an error
Track Thymalin research, inventory and reconstitution in the free Peptide Library app. Get the app for iOS or Android →