In phosphodiesterase Type 5 inhibitor, the major ingredient is Sildenafil which also doubles as the active ingredient in Viagra. The pill is made up of a compound called phosphodiesterase Type 5 inhibitors. Researchers at New York University School of Medicine gave L-arginine to a group of 15 men and found that six received benefit. The protocols were changed by a group of physicians, including the medical board and Bailey doctors, in July 2018, she said.