Thymopentin (TP5) is an immunomodulator, resembling the active site of the thymopoietin. TP5 stimulates cellular immune responses such as T-cell formation, natural killer (NK) cell and macrophage activation generation of cytokines, and activation of B-cell for antibody production. It also mimics the polypeptide environment of the thymus. TP5 is used to treat conditions like immune deficiency, autoimmune diseases, infections, and cancers. It has a short half-life and is rapidly metabolized in the gastrointestinal tract.