Endothelins are powerful vasoconstrictor peptides that play numerous other roles. Endothelin-1 (ET1) is the principal isoform produced by the endothelium in the human cardiovascular system. Endothelin-3 (ET3) and its rPptor affinity have been demonstrated to support neuronal repair mechanisms throughout life. https://www.roneverhart.com/Cyspera-Pigment-Corrector-1-75oz-52ml/