Hi Rebecca, we love hearing that you love our NAD+ formulation! Yes, some people might experience a sense of tingling, or heat or redness in the skin, or a sense of flushing when taking Qualia NAD+. Qualia NAD+ contains 3 different NAD+ precursors: (1) nicotinamide riboside, (2) niacinamide, and (3) niacin (nicotinic acid). The first two, nicotinamide riboside and niacinamide, are typically described as being non-flushing. The niacin (nicotinic acid) form of vitamin B3 can cause flushing; however, this usually only occurs when it is supplemented in amounts of 30 mg or more. In studies, it has been very rare to experience a niacin flush with 30 mg of nicotinic acid, but about half of people experience flushing when taking 500 mg of nicotinic acid. We formulated Qualia NAD+ to have less than 30 mg of the nicotinic acid form to reduce the chances of flushing—a 2 capsule serving of Qualia NAD+ only contains 20 mg of the flushing type of vitamin B3. Because of this, we expect flushing to be a rare experience when taking Qualia NAD+. But individual differences (i.e., genetics, gut microbiome, etc.) may make some people more prone to experiencing a niacin flush when supplementing even low amounts of nicotinic acid (and possibly even the non-flushing forms of niacin). Niacin flushing can be felt anywhere along a continuum of being a mild tingling sensation to feeling very uncomfortable—it can be experienced as feeling a lot like an allergic reaction. While it can be uncomfortable, a niacin flush is considered to be harmless and temporary, usually taking less than 1-2 hours to go away on its own. A general rule of thumb is that flushing is most intense after the first time someone takes a supplement containing nicotinic acid, and typically diminishes over days or weeks with continued use. However, flushing from low amounts of nicotinic acid can also occur sporadically and unpredictably. In other words, it's possible to take a supplement many times and never flush, and then one day experience flushing unexpectedly.