However, considering that NA can be metabolized to nicotinamide in vivo,54 it can be postulated that clinical efficiency of topically administered NA might even be superior to the one of nicotinamide, since theoretically, it could include both HCA2‐dependent direct, and, following its conversion to nicotinamide, HCA2‐independent, indirect anti‐acne effects. Here, HCAR2 is linked to acne.