The main ingredient, green tangerine is supposed to have much more vitamin C content than regular citrus products, so I was really excited to try this out. previously I used the iunik vitamin C propolis serum but got some skin reaction to it. When I first tried this out, I was also trying other new products, so the combination of the new products caused my skin to breakout quite a bit in little red bumps, but after my skin calmed down this product worked well. I'm not quite sure about the brightening power yet since I have only used it for about a month. Regardless I think it's a good and simple product for people who think serums might be too heavy.