I use this during my nighttime skin care routine. I cleanse, tone and then apply this. The glycolic axid along with AHA/BHA is provides great chemical exfoliation. I have been using this faithfully for about two years now and will not stop. I usually buy this from Sephora and stock up on a few bottles when they are having their VIB sales.
Also, the bottle is not penetrable to light so the product doesn’t not degrade and the pump style protects it from being degraded by air!