The penis is one of the areas where this enzyme works. As discouraging as that may seem, that’s a big part of how profit in a capitalist system works. By controlling the enzyme, sildenafil helps to maintain an erection after the penis is stroked. The amount of medicine that you take depends on the strength of the medicine. How oral medicines differ Each oral medicine for ED has a slightly different chemical makeup. Its effects might last longer if you have mild to moderate ED. · Red ginseng Fenugreek Saffron Ginkgo biloba L-citrulline A quick look at the best supplement products to help boost libido Best with maca: NaturaLife Labs Maca .  · Studies have shown that propionyl-L-carnitine combined with Viagra might improve erectile function better than sildenafil alone. Propionyl-L-carnitine is likely to be .  · Revatio Viagra Descriptions Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines .