Yes, a very small number of people might experience heat or redness in the skin or a sense of flushing when taking Qualia NAD+. Qualia NAD+ can increase circulatory function, increased heart rate or flushing. This is due to the nicotinic acid (niacin) form of vitamin B3 when taken in amounts substantially more than the daily value (DV) amount. Qualia NAD+ contains nicotinic acid, but in an amount below the level where flushing has occurred in studies.  The other common form of vitamin B3, niacinamide, does not cause flushing. NIAGEN® Nicotinamide Riboside, a next generation vitamin B3, also does not cause flushing.* If you continue to take Qualia NAD+ and the flushing continues and/or is uncomfortable, we recommend discontinuing use for a day or two and start again with a lower dose. For most people who experience this it will stop within a couple of days.