This Vitamin May Influence Your Blood Flow and Blood Vessels—Here’s What Science Says

a vitamin deficiency.

Niacin’s effects on blood vessels are real but easy to exaggerate—the more important question is whether vitamin B3 can actually improve the conditions that cause persistent problems in the legs and feet.

Niacin, Legs, and Feet

Cold feet, leg discomfort, numbness, swelling, cramping, and difficulty walking are sometimes casually described as symptoms of “poor circulation.”

But these symptoms can have many different causes.

Leg pain while walking, for example, can sometimes occur with peripheral artery disease, in which narrowed arteries reduce blood flow to the limbs. Other causes can include nerve problems, arthritis, spinal conditions, muscle disorders,