Thymalin

Thymic peptide bioregulator · Also known as Thymic polypeptide complex, Thymaline

What is thymalin?

A polypeptide complex extracted from calf thymus glands, containing short peptides of 2 to 8 amino acids that regulate T cell maturation and immune function. Developed in Russia in the 1970s by Professor Vladimir Khavinson at the St. Petersburg Institute of Bioregulation and Gerontology.

Thymalin has over four decades of clinical use primarily in Russia and Eastern Europe for immune restoration in aging, infection recovery, and post-chemotherapy immune suppression. A long-term clinical study in 266 elderly patients showed that combined thymalin and epithalamin treatment was associated with significantly reduced mortality compared to controls, though these results come from Russian studies that have not been independently replicated. It was also studied in severe COVID-19 patients, where it accelerated lymphocyte recovery and reduced inflammatory markers.

Key takeaway: Thymalin has the longest clinical track record of any thymic peptide bioregulator, with Russian longevity data suggesting reduced mortality in elderly patients over 6 to 8 years of follow-up, though independent replication is lacking.

Benefits & evidence

Immune system restoration Moderate confidence
Reduced mortality in elderly Moderate confidence
T cell maturation support Moderate confidence
Infection recovery Moderate confidence
Anti-aging / longevity Preliminary confidence

How it works

Thymalin contains several bioactive dipeptides and tripeptides (including EW, KE, and EDP) that regulate gene expression in immune and hematopoietic cells. These short peptides influence the synthesis of heat-shock proteins, cytokines, and factors involved in cell differentiation, proliferation, and apoptosis. The primary effect is restoring T cell populations that decline with age-related thymic involution.

Clinical studies in elderly subjects have documented normalization of total T lymphocyte counts, improved natural killer cell activity, balanced Th1/Th2 cytokine profiles, and enhanced phagocytic activity of neutrophils and macrophages. In COVID-19 patients, thymalin accelerated recovery from lymphopenia and normalized C-reactive protein, D-dimer, and NK cell counts faster than standard therapy alone. The peptide complex also reduces the incidence of acute respiratory infections by 2 to 2.4-fold in treated elderly populations.

Dosing information

Typical dosing protocol
Starting dose

5-10 mg/day

10-day course
Maintenance dose

5-10 mg/day for 10 days

Repeated 2-4 times per year, spaced 3-4 months apart

Administered by subcutaneous or intramuscular injection. Based on protocols from Russian clinical studies by Khavinson et al. spanning multiple decades. In the landmark longevity study, patients received annual courses of thymalin (sometimes combined with epithalamin) for up to 6 years.

Side effects

Most side effects tend to improve as your body adjusts.

Injection site reaction Common
Mild fatigue during initial course Uncommon
Allergic reaction Rare