Most compounds in this catalogue have to be explained by what is missing: no label, no registered trial, a dose figure that traces back to a vendor. Thymalin is the reverse case at first sight. It has a current prescription registration, a manufacturer, and an instruction with exact figures for adults and children. The complication is what that label is for. Its active ingredient is not a peptide with a sequence but an extract of calf thymus.
What thymalin is and how it is described is on Peptide Lexicon's thymalin entry. This page reports the label figures and what sits behind them.
Where it is registered
The Vidal drug reference, read on 4 October 2026, lists Тималин (Thymalin) as a prescription medicine registered in Russia under ЛП-№(005867)-(РГ-RU) of 21 June 2024, open-ended, replacing the earlier registration ЛС-000267. The holder is Samson-Med LLC; the ATC code is L03AX, other immunostimulants. We found no US label, no EU authorisation and no ClinicalTrials.gov record. That is the "where was it filed" answer: in the Russian system, and nowhere else we could find.
What is in the vial
| Component | Amount per vial |
|---|---|
| Thymus extract (from calves and cattle up to one year old) | 10 mg |
| Glycine (excipient) | 20 mg |
| Form | Freeze-dried powder for intramuscular injection |
The label names the active substance as "thymus extract", grouped as such. It is a mixture of peptides isolated from animal tissue, not one defined molecule. This matters for any figure on this page: 5 mg of thymalin is 5 mg of that extract. A research-market vial sold as "thymalin" may contain something else — a synthetic short peptide, an extract from another source — and the label's figures say nothing about it. What a certificate of analysis can and cannot establish for a mixture is on our COA guide.
What the label states
The instruction's dosing section reads, in our translation:
| Group | Daily intramuscular amount | Course |
|---|---|---|
| Adults (treatment) | 5–20 mg | 30–100 mg in total; 3–10 days |
| Children 6–12 months | 1 mg | 3–10 days |
| Children 1–3 years | 1.5–2 mg | 3–10 days |
| Children 4–6 years | 2–3 mg | 3–10 days |
| Children 7–14 years | 3–5 mg | 3–10 days |
| Adults (prevention) | 5–10 mg | 3–5 days |
| Children (prevention) | 1–5 mg | 3–5 days |
Course length depends on "the severity of immune impairment", and a repeat course may be given after one to six months. The label states there are no data on dosing in kidney or liver impairment or in older patients — which is notable given that most current marketing is aimed at older adults.
The arithmetic is simple because the label is in milligrams per day, not per kilogram: an adult course of 30–100 mg is three to ten vials. One vial reconstituted in 1 mL gives 10 mg/mL; the label figures do not specify a volume, and the reconstitution arithmetic for any vial is on our reconstitution guide.
What it is registered for — and what it is not
The listed indications are immunodeficiency in adults and children from six months with:
- purulent and septic infections;
- persistent thymus dysfunction — radiation sickness, thymic tumours, surgical removal of the thymus;
- acute and chronic viral and bacterial infections;
- impaired tissue repair;
- suppressed immunity and blood formation after chemotherapy or radiotherapy.
Ageing, longevity and "immune rejuvenation" are not on the list. Those uses come from a body of Russian gerontology research, chiefly from the St Petersburg Institute of Bioregulation and Gerontology, which also produced the epitalon literature covered on our epitalon dosage page.
The trial record
ClinicalTrials.gov returned no study naming thymalin on 4 October 2026. PubMed returned 234 records with thymalin in the title or abstract, 12 tagged as clinical trials; five of the seven we opened were in Russian- or Ukrainian-language journals, in settings such as peritonitis in children, tuberculosis, pancreatitis, ulcerative colitis and parkinsonism.
The most cited English abstract is Khavinson and Morozov (2003): 266 elderly people followed for six to eight years, with thymalin, epithalamin or both given in the first two to three years, and a reported two-fold lower mortality in the thymalin group than in controls. The abstract does not state the dose, the course schedule or how participants were allocated to groups, so the figure cannot be checked against the label from the abstract alone. A mortality claim of that size, from one research group, with no registration, has not been reproduced in any trial registered outside Russia that we found.
Safety, as the label gives it
The side-effect section reads in full: "possible: allergic reactions." The instruction contraindicates use in pregnancy and breastfeeding and in hypersensitivity, urges caution with a history of allergy, and lists the perimenstrual period and endocrine conditions such as pituitary adenoma and acromegaly as relative contraindications for bovine thymus peptide products. It advises against alcohol during use.
A one-line adverse-reaction section is what a label of this age and evidence base contains; it is not a measurement. Because the product is sourced from cattle tissue, the identity and contamination questions differ from those for a synthetic peptide, and the label does not discuss them. How thymalin's record compares with the synthetic thymic peptide that is approved in some countries is on our thymosin alpha 1 dosage page.
What this page is and is not
It reports what the Russian instruction states for its own registered product, with the date it was read. It is not a protocol and does not cover research-market vials, whose contents the label cannot vouch for. Anyone considering a thymus-derived product should discuss it with a doctor who knows what the product is.
Sources and dates
- Vidal drug reference (vidal.ru), Тималин® лиофилизат для приготовления раствора для внутримышечного введения 10 мг: composition, registration, indications, dosing regimen, side effects, contraindications, special instructions (read and translated 2026-10-04).
- ClinicalTrials.gov v2 API, term "thymalin" (0 studies, read 2026-10-04).
- PubMed E-utilities: thymalin[tiab] 234 records; with clinical-trial or randomised filters 12 (read 2026-10-04).
- Khavinson VKh, Morozov VG. Peptides of pineal gland and thymus prolong human life. Neuro Endocrinol Lett 2003;24:233–40, PMID 14523363 (abstract read 2026-10-04).
Corrections go to the contact page.