I visited two dermatologists to get a very large dark spot under my eye looked at. They biopsied it and said it was simply sun damage. Unfortunately, because it was so close to my eye, they said laser treatment was not an option. Even heavy makeup and corrective product applications couldn't hide the spots, and friends and family members -- even doctors -- would ask me if I'd had it checked (yes, I had). I'm actually glad they said this, because I never gave up on trying to change this. Two years ago, a third doctor directed me to Obagi products. She assured me that after treating my large sunspot and two smaller but no less visible areas on my face, I'd see a significant reduction in the size and darkness of the marks. After two days, the skin started to peel slightly and redden where I applied it. After a week, the center of the spots were noticeably lighter than the edges. After a month, I could definitely see a difference when I looked in the mirror. Now, a few years later, I apply it after I notice the marks deepening in color again. The skin reddens slightly, but doesn't generally peel. One of the larger blotches on my left cheek (thank you, driver's side car window), has faded almost entirely, and a spot under the left eye is nearly invisible with just a light application of makeup. Even on days when I go makeup-free, I don't find people staring at my spots, and family members don't ask in concern if I have skin cancer. After 40 years of being exposed to the Florida sunshine, I'm finally starting to undo some of the visible damage, and I have this product to thank. Effectiveness As I said above, fantastic results. One note: it may cause irritation and burning. I use Vitamin E oil on my face for a few days afterwards.