Thymalin

Also known as: Thymic extract, Thymus extract

Evidence: Clinical

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Overview

Peptide extract of calf thymus, registered in Russia as a 10 mg injectable lyophilizate; its developers tested it as add-on therapy for COVID-19 in an open-label randomized trial (n=92).

Thymalin is a complex of peptides extracted from calf thymus, registered in Russia (ЛП-№(005867)-(РГ-RU), 21 June 2024) as a 10 mg lyophilizate for intramuscular injection. It is not a single synthetic peptide; its developers report the dipeptides KE (Vilon) and EW (Thymagen) in its composition (Linkova 2023). The strongest human study is an open-label randomized trial in COVID-19, 42 treated vs 50 controls, 10 mg IM daily for 5 days, run by the developer group (Khavinson 2021). An older report from the same group described longer survival in elderly people given thymus and pineal peptides, with a weak design (Khavinson 2003). T-activin is a different thymus product.

Benefits

Registered drug in Russia (intramuscular lyophilizate), add-on therapy in COVID-19 (human open-label RCT, n=92, developer group), longer survival in older adults (human, weak design, developer group), hematopoietic stem cell differentiation (human cells)

Dosing reference

Research dose: 5 to 20 mg IM daily for 3 to 10 days (Russian label, adults)
Range: 5000 to 20000 mcg, 1x daily
Common vial sizes: 10 mg

Intramuscular only. Russian label: 10 mg lyophilizate per vial; adults 5 to 20 mg daily for 3 to 10 days. The COVID-19 trial used 10 mg IM daily for 5 days (Khavinson 2021). No oral form is registered.

Mechanism

Proposed. As a mixture its action has not been tied to one molecule. The developers report that it activates differentiation of human hematopoietic stem cells (Khavinson 2020). They identify the dipeptides KE and EW in the drug and report that both alter expression of genes and proteins involved in COVID-19 pathogenesis (Linkova 2023). A 1997 review from the same group places it among natural and synthetic thymic peptides for immune dysfunction (Morozov 1997). Restoration of the thymic microenvironment is a hypothesis, not a measured effect.

Evidence

Clinical: at least one published human trial or an approved drug

Open-label randomized trial in COVID-19: 42 patients given 10 mg IM daily for 5 days within complex therapy vs 50 controls, run by the developer group (Khavinson et al., 2021)
Activated differentiation of human hematopoietic stem cells (Khavinson et al., 2020)
The dipeptides KE and EW, identified in the drug, altered expression of genes and proteins linked to COVID-19 pathogenesis (Linkova et al., 2023)
Older adults given thymus and pineal peptide courses had longer survival in a weakly designed report from the developer group (Khavinson and Morozov, 2003)
Human-trial status: registered drug in Russia (label: adults 5 to 20 mg IM daily for 3 to 10 days); one open-label developer-run RCT; no independent trial

References

Side effects

No independent safety study has been published; the developer-run trial and survival report were not designed as safety studies. Commonly reported (anecdotal): injection-site pain and transient local reactions.

Storage

Storage: Room temperature
Lyophilized: 24+ months

Pharmacology

Half-life: No published pharmacokinetic data; a mixture of peptides
Bioavailability: Given by intramuscular injection only (Russian label); no published pharmacokinetic data