Peptide LibraryThymalin
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
- Evidence level
- Limited Human Evidence
- Human dose established
- No
- Administration Route
- Not established in humans
- Frequency
- Not established in humans
- Last updated
- Nov 7, 2026
- Reviewed
- Nov 7, 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 Oct 2026 and Nov 2026, so confirm the live price on the vendor site. Peptide Library does not sell peptides.
- Vendors listing this peptide
- 14
- Listed offers
- 18
- Median price per mg
- $4.50/mg
- Typical $4.01–$5.67/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.
Research evidence
- Regulatory review (FDA label)None in reviewed sources
- Controlled human trials1 reviewed source
- Early or uncontrolled human studies1 reviewed source
- Lab & animal studiesNone in reviewed sources
How it works
Each step shows whether the sources Peptide Library has reviewed include that kind of research. Counts are reviewed sources, not every study ever published. Reviews and programme summaries that describe human use are shown as "reported", not as trials, and registered trials without published results are listed but not counted. A higher step means research has progressed further; it does not mean a compound works better or is safer. Compounds whose evidence has not been reviewed yet show "Not reviewed" instead of a guess.
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.
Thymalin dosage: no established human dose
Thymalin has no established human dosage outside Russia. It is a calf-thymus peptide preparation studied mainly in Russian and Ukrainian clinics; the largest report followed 266 older people given thymalin or the pineal preparation epithalamin over 6–8 years. The indexed English abstracts of these studies do not state the dose, and no trial is registered on ClinicalTrials.gov.
No established human dosage.
Human clinical evidence: None identified.
Preclinical research: Thymalin is a mixture of peptides extracted from calf thymus, used in Russia as an immune-modulating medicine. Its clinical literature is mostly Russian-language, from a small number of groups, and the indexed records do not give the amounts used, so no dose, interval or course length can be stated from verifiable sources.
Animal dosing is not converted into a human dose anywhere on this page. Where research figures appear below, they are reported as studied, not recommended.
| Human dosing established | No |
|---|---|
| Route | Not stated in the indexed human studies |
| Evidence level | Limited Human Evidence |
| Last reviewed | 2026-11-07 |
Human research reported
Doses as studied, one row per regimen. Different trials used different regimens; they are listed separately rather than averaged.
| Study / context | Population | Dose | Route | Frequency | Duration | Outcome studied | Source |
|---|---|---|---|---|---|---|---|
| Long-term follow-up of thymic and pineal peptide preparations (2003)Clinical trial · Controlled observational clinical study | Elderly and older adults (n=266, including epithalamin and combined groups) | Not stated in the indexed abstract | Not stated in the indexed abstract | — | Given during the first 2–3 years of 6–8 years of observation | The authors report lower respiratory illness and mortality than controls | Peptides of pineal gland and thymus prolong human life. Neuro Endocrinol Lett. 2003. |
| Pulmonary tuberculosis, combined treatment (1990)Clinical trial · Clinical study | Patients with pulmonary tuberculosis | Not stated in the indexed record | Not stated in the indexed record | — | — | Not available in the indexed record (Russian-language article) | [Effectiveness of administration of thymalin in the complex treatment of pulmonary tuberculosis]. Probl Tuberk. 1990. |
Where sources disagree
- Thymalin is a tissue extract, not a single defined peptide, so its strength can differ between products. Figures for one product do not transfer to another.
- Much of the longevity claim rests on one long-term study by a single research group that combined thymalin with epithalamin. It has not been reproduced in a registered trial.
Reconstitution
Common research vial sizes: 10 mg, 20 mg.
| Vial | Bacteriostatic water | Concentration | Per 0.01 mL |
|---|---|---|---|
| 10 mg | 2 mL | 5 mg/mL | 50 mcg per 0.01 mL |
| 20 mg | 2 mL | 10 mg/mL | 100 mcg per 0.01 mL |
These figures are arithmetic only — they convert a vial and a volume into a concentration. They are not a recommendation to take any dose.
Calculate reconstitution & dose →Handling & administration
- Timing Notes
- Immunomodulatory thymic preparation; not FDA-approved.
Sequence & 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]
Research statistics
272 PubMed publications · 33.1% human clinical research · 0 registered trials
Counts of published research through 2026-11-01, not evidence that it works. Publications by year, study types and trials · How publications are counted
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 |
How FDA approval, compounding and research-only status differ
Benefits
Thymalin side effects
Thymalin has only limited human data, so the list below is incomplete and its side-effect profile is not well established.
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
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Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Nov 7, 2026 · Version 2
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
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