This is my third repurchase of the Kora Vitamin C serum. Although subtle, I do see a noticeable brightness to my skin. This is one of my holy grail facial products. I highly recommend this to those who will add vitamin C to their facial regimen. I use this in the morning along with their new plant stem cell serum. I have in the past tried to add retinal to my facial care. It has been a disaster! Inasmuch as I have never had a problem with anything I have purchased from Kora Organics I took a chance. I am so glad I did! This too will be a staple in my skincare regimen.