Niacin side effects swollen lower lip could taking 1800mg of niacin induce a swollen lower lip?

Possibly: While it's not possible to overdose on Niacin simply by eating too many niacin-rich foods, taking too much over-the-counter or prescription Niacin can be dangerous. You may have heard that too much Niacin can be harmful because of internet rumors. The rumors falsely state that by taking a large amount of niacin, people can flush the chemicals that show they've used marijuana out of their bodies.