Been using this almost nightly for close to a month, in conjunction with the OST Vitamin Sleep 9 to 5 cream, and I have noticed a gradual fading of fresh pimple scars.  Cannot yet see other claims of blackhead removal, whitening etc... Although Vit C as an antioxidant should fight the effects of aging over long periods of use.  I find the serum quite sticky and stinging on the face, so I'm not sure if I will keep using it as I do not have much pimple/acne problems to begin with.