Renholder, I think both. More/better bloodflow is what vasodilators like nox do, they widen the blood vessels, so more blood can be supplied.
Also gingko is a good supp for blood circulation. Good for brain function as well.
Hormonal change like increased testosterone will give better erections. Eating broccoli is a natural way to improve testosterone. A full body exercise like squatting also improve’s testosterone.
About the goji berries I mentioned before.. It’s best to buy them in a reform shop. There’s a big change that the goji’s you buy on the market contain DDT which is not good.
(What is DDT? http://en.wikipedia.org/wiki/DDT )
I, can, I can, I can not, can not compute..