I used to use 22% with no burn but I wasn鈥檛 able to find it on 麻豆区 so I purchased this, 35% and god it burns. I don鈥檛 even have sensitive teeth and yet it burns. I also don鈥檛 know that there鈥檚 a difference in whitening between this and the 22% as I haven鈥檛 noticed anything. I really wish the 22% brand will restock cause this feels like he鈥檒l.