I think Polaiya's products are very suitable for college students. Young skin still needs basic care. Polaiya has been focusing on marine skin care and advocating natural ingredients. I have been using Polaiya's nicotinamide essence suit recently. I prefer to call it the luminous bottle. It is said that 28 days is brand new. I don't know if the effect cycle is 28 days. I have used it for 20 days now, which not only has obvious whitening effect, but also changes every day. Thank you for your question. I hope it helps your problem.