When using 377, it should be noted that 377 can't be used with salicylic acid, and 377 whitening essence can't be used with things containing copper peptides, because copper peptides will oxidize vc inside. Secondly, try not to use it with nicotinamide, because nicotinic acid may be produced, and other fruit acids should be avoided. 377 can improve skin tone and reduce the black color of ultraviolet radiation. Esme ACM Brightening Essence Cream contains nicotinamide and cannot be used together.