Doctor's Best Sustained-Release Niacin with niaXtend provides niacin in a form that helps minimize the incidence of uncomfortable skin flushing that is commonly associated with niacin. Approximately 200 coenzymes are comprised of niacin that play pivotal roles in metabolism and energy production within the body. niaXtend has been tested to encourage a favorable blood lipid profile. Research suggests that niacin, in combination with a well-balanced diet, may help maintain healthy cholesterol levels that are already within the normal range.