Can I use Epiduo and serum with niacinamide?

According to the epiduo package leaflet, avoid the concomitant use of Epiduo and cosmetics that cause irritation, dryness or exfoliation of the skin. Niacinamide in a concentration of up to 5% has regenerating properties, but above this value it can cause irritation and redness. So it depends on what serum you are asking about and whether niacinamide is the only ingredient. I would suggest starting by observing how your skin reacts to Epiduo and combining it with mild moisturizing care (best tested on your skin). If the skin reacts well (no irritation, peeling, burning), you can consider using a product with niacinamide in a low concentration (3-5%), but not every day. In terms of proper care, it is worth consulting a dermatologist or cosmetologist - an interview and viewing of the skin is crucial to determine its needs and possible contraindications to the use of certain care ingredients. I enclose information that may be of interest: https://www.gdziepolek.pl/artykuly/jak-pozbyc-sie-tradziku-u-doroslych https://www.gdziepolek.pl/kategorie/tradzik https://www.gdziepolek.pl/produkty/27377/epiduo-zel/apteki/w-warszawie