Thymalin

What Is Thymalin?

Thymalin is the Khavinson thymic bioregulator: a low-molecular-weight polypeptide complex extracted from calf thymus, developed at the St Petersburg Institute of Bioregulation and Gerontology from the 1970s onward. Unlike Thymosin Alpha-1, a single defined 28-amino-acid synthetic peptide, Thymalin is a mixture of short peptides (mostly di- to tetrapeptide fractions under 10 kDa) co-extracted from thymic tissue and standardised by biological activity rather than by sequence. Its active fraction inspired the synthetic dipeptide Thymogen (Glu-Trp), but Thymalin itself remains the original extract-based bioregulator used in Russian clinical practice.

The proposed mechanism is restorative rather than agonist. Thymalin drives age-suppressed thymocytes through maturation into functional T-cell subsets, restores the CD4/CD8 ratio toward a younger pattern, normalises natural killer cell activity, and rebalances cytokine output, raising IL-2 in immunosuppressed states and dampening IL-6 in chronic inflammation. Khavinson's group has also reported gene-expression normalisation (Mybl1, Per1, IGF-1) in elderly cohorts and restoration of antioxidant enzymes (superoxide dismutase, glutathione peroxidase). Because the reported changes are in cellular populations and gene expression rather than receptor occupancy, the effects measured in the cohort studies persisted well beyond the exposure period. The evidence base is almost entirely Russian-language and from the originating institute.