Niacin, vitamin B3.
Niacin, a form of vitamin B3, has been studied, but the results are still inconclusive. But here's what we can say: According to a recent study, middle-aged and older adults who take niacin have better blood flow. The study focused more on niacin's beneficial effects on the endothelium, a thin cell lining that lines your blood vessels and is crucial for blood flow and sexual function.you can watch another vitamins in video.