The first time I used it, because I had a lot of dark spots, when I rubbed it on my forehead where they were more intense, it left brown marks on the cotton pad. I couldn't believe it!!!! This was initially recommended to me by the pharmacist after I got dark spots on my face, but together with the rest of the series... I believe it will work on its own, but if you also get the sunscreen, serum, and cream, the result is INCREDIBLE. This is the sixth time I am buying it, I just get it through Skroutz because the whole package is more affordable than at the pharmacy. It's worth it for dark spots, get it without a second thought, but in my opinion, with the whole series!!