SkinStruct review for Vitamin C Brightening Serum

I’m not sure how effective vitamin C derivatives are. I did not notice a significant difference in my skin. I did not notice my hyperpigmentation lightening or my skin brightening. With pure L-ascorbic acid serums, I do notice brightening within a few days. Maybe I need to use this longer, so I will update later. I do not llike the fact that this contains retinol in the ingredients list. Vitamin C serums are generally supposed to be used in the morning and retinol should only be used at night. It is listed near the end of the ingredients list, so the concentration is probably very low. But then what is the point of including it in the serum to begin with? Retinol risks sensitizing the skin during the daytime in sunlight, so including it in a vitamin C serum that is generally supposed to be used in the AM doesn’t make sense.