TB-500 is the synthetic version of the naturally occurring peptide thymosin beta 4. Thymosin beta 4 is the most abundant thymosin in human cells and tissues, consisting of 43 amino acids. The fibrinolytic system is essential for restoring blood vessel blockage or obstruction following clot formation. Fibrinolysis is the breakdown of fibrin in blood clots, and abnormalities in this system may be associated with thrombosis. Thymosin beta 4 has the ability to induce fibrinolysis and has been shown to reactivate progenitor cells to repair damaged tissue. Thymosin beta 4 may have the ability to inhibit myocardial cell death, as well as activate endogenous cardiac progenitors. It may not only improve cardiac function, but may also decrease mortality rate as a result of cardiac rupture.