Vitamin B3 (niacin)
Niacin, specifically nicotinic acid, can cause vasodilation of small blood vessels, producing the familiar “niacin flush” (redness, warmth, tingling or itching).
However, that does not mean taking niacin supplements is a good way to improve circulation or prevent heart attacks/strokes. Current cardiovascular guidance does not recommend dietary supplements as a general treatment for high cholesterol, and niacin should not be taken in high doses without medical supervision.
What about vitamin C?
Vitamin C is also involved in healthy blood-vessel function and nitric-oxide production, which can support vasodilation. But taking extra vitamin C when you already get enough from food isn’t proven to dramatically “open blocked arteries” or fix poor circulation.
Bottom line: No vitamin can safely “unclog” arteries or serve as a substitute for treatment of high blood pressure, high cholesterol, or peripheral artery disease. If you’re having cold/numb feet, leg pain when walking, swelling, or other circulation symptoms, the underlying cause should be evaluated.
