What Is Thymalin?

Also known as: Thymic peptide bioregulator, Thymus extract peptide

Thymalin is a polypeptide complex extracted from calf thymus, standardized by the Khavinson group in St Petersburg and used in Russian medicine since the 1980s as an immunomodulator. Its synthetic dipeptide cousin, thymogen, is derived from the same work.

Its research story is immune restoration in aging: short courses were reported to normalize T-cell subsets, and a 6–8 year study in elderly patients reported lower rates of infection, cardiovascular disease and overall mortality in the treated group.

What is Thymalin studied for?

Side effects & safety

Rarely reported — injection-site reactions and occasional low-grade fever. As a biological extract, batch consistency matters more than for synthetic peptides.

Legal & approval status

Registered medicine in Russia; not approved in the US or EU. Sold internationally as a research peptide.

Typical dosing at a glance

Commonly reported protocols use 5 mg–20 mg, daily for 5–10 days, cycled 1–2x per year, via subcutaneous injection. For the mixing math — how much bacteriostatic water, exact syringe units, doses per vial — see the Thymalin reconstitution calculator →

Related peptides

What is LL-37?What is Thymosin Alpha-1?What is VIP (Vasoactive Intestinal Peptide)?

Educational overview based on published research and commonly reported community protocols — not medical advice, and not an endorsement of any compound. Consult a licensed healthcare provider.