Thymalin is a polypeptide medication used for treatment of various diseases associated with immune dysfunction, viral and bacterial infections or regeneration issues, immunodepression, and post-chemical and radiotherapy hematogenesis depression. It has immunomodulatory and antiviral effects studied in numerous researches. Thymalin and its components function by regulating gene expression and synthesizing heat-shock proteins, cytokines, fibrinolysis, gerontogenes, as well as influencing cell differentiation, proliferation, and apoptosis. Thymalin exhibits minimal side effects and could be effective against various viral infections, making it potential candidate for the complex therapy for example of COVID-19.