Hi Brian, thank you for your product review. Qualia NAD+ can increase circulatory function. The nicotinic acid (niacin) form of vitamin B3 can cause flushing 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. A very small number of people might experience heat or redness in the skin or a sense of flushing. If it’s uncomfortable, discontinue use for a day or two and start again at a lower dose. For most people who experience this it will stop within a couple days. Please reach out to the customer support team for further concerns. Thank you!