Coming from a medical aesthetician (skin care professional & specialist) this serum has by far proven its self! I’ve used so many other vitamin C & brighting agents in the skincare industry and this serum knocks them all! I would chose this over medical grade vitamin C serums in a heart beat! I use this AM only. When I first started this serum, I saw improvement in my skin in just two weeks! This is a must have product in your skin regimen! Helps prevent & control pigmentation, acne scars have no chance! Being a skin care junkie I strive to have glass skin & this product over delivered!!! So glad I found this!