Niacinamide is pronounced as "NYE-a-sin-a-mide" or "niacin-am-ide". It is a form of vitamin B3 (niacin) and is used to prevent and treat niacin deficiency (pellagra) . Unlike niacin, niacinamide does not help correct blood fat levels and cannot be substituted for niacin if you are being treated for a blood fat problem (such as high cholesterol) . Niacinamide is generally well-tolerated in usual doses, but upset stomach, nausea, and diarrhea may occur. If you have any allergies or health problems, it is best to consult your doctor or pharmacist before using this product. Niacinamide is a common ingredient in skincare products due to its ability to improve skin texture, reduce inflammation, and regulate oil production.