The stabilities of nicotinamide in cosmetics under different temperature and storage & transportation conditions were explored.We detected the content of niacin in nicotinamide produced by 5 manufacturers, and the changes of niacin content stored under 8 different conditions for 120 d and simulated during storage and transportation in summer.The results showed that the 5 niacin contents were quite different between 5 samples.The conversing from nicotinamide into niacin was accelerated by light, high temperature, storage and transportation in summer.So the cosmetics with nicotinamide should be stored and transported under low temperature and dark conditions as far as possible, and its transporting time in summer should be reduced as well.