Thymosin Alpha-1 (Talpha1) is a 28-amino-acid peptide originally isolated from thymic tissue and later manufactured synthetically. Research has examined effects on dendritic-cell maturation, T-cell responses, natural-killer-cell activity, Toll-like-receptor signaling, and cytokine balance. It has been studied internationally in viral disease, immune dysfunction, vaccine response, and oncology-adjunct settings. Regulatory status varies by country, and it is not an FDA-approved drug in the United States.