Flush-free niacin is marketed as an alternative to regular niacin, or vitamin B-3, supplements that can cause a flushing sensation or redness of the skin. These products have markedly reduced beneficial effects, according to the University of Massachusetts Medical School.
Niacin is often recommended to raise HDL (high-density or "good") cholesterol and to lower LDL (low-density or "bad") cholesterol. Extended-release forms are less likely to produce flushing, the UMMS says. To minimize side effects from niacin, start with a low dose and work up to the appropriate dose. Always take it with a food or a snack to prevent stomach ache.
An article in the medical journal "Preventive Cardiology" reports that a patient who was instructed to take an extended-release form of niacin but bought and took the flush-free form had no significant changes in his cholesterol levels. When he switched to an extended-release form, the anticipated benefits were seen. The author concluded that flush-free niacin may also be benefit free.
A class-action lawsuit was filed in March 2014 against a manufacturer of flush-free niacin. It alleges that the company misrepresented the supplement as promoting heart health when it actually had no effect on any condition that improves heart health, according to Truth in Advertising.