I use this a few times a week before going to bed, or sometimes in the morning before I go out (I wear sunscreen over it for protection and no makeup). The scent took awhile to get used to but I can tell it's very concentrated. My skin feels healthier after using it.
This is a potent vitamin c serum. It does sting upon first applying it, but the stinging subsides after a few minutes and so far it has made a difference with some of my hyperpigmentation skin issues.