Niacin Flush: The Skin-Flushing Side Effect, Explained

Niacin (Vitamin B3) is well known for a specific, harmless-but-startling effect worth understanding before your first dose.

What the flush actually is

Niacin can cause temporary skin flushing, warmth, and sometimes mild itching or tingling — a well-documented, generally harmless reaction related to how niacin affects blood vessels near the skin's surface, distinct from an allergic reaction.

What to actually do if it happens

The flush typically passes within 20 to 60 minutes and often lessens with continued regular use — worth noting when it happens and mentioning it at your next doctor visit if it feels unusually intense or doesn't ease over time.