Vitamin E is probably the best thing in the world for blood vessel health. It is also good for skin elasticity. I take vit E orally and slather pure E oil onto my dick at the beginning of every girth session. If I'm hanging, I slather the oil on the base of the shaft after I get rigged up.
Vitamin E has tons of beneficial effects on physiology... everyone here should read up on it.
BTW, I used to be a store manager for General Nutrition. I had to study up on all the supplements, and to this day I take a good multi plus a low dosage vit C supp, and 200 IU of vitamin E daily.