Niacin CRTHelps the body metabolize carbohydrates, fats and proteins Niacin CRT is a unique wax matrix tablet, which uses the latest controlled release technology (CRT). This technology delivers niacin at a continuous, controlled rate over a period of 6 to 8 hours, throughout the transit time of the tablet through the intestine. Hot flashes sometimes occur with extended release niacin, as there can be quite large bursts of niacin released intermittently.