At first, this serum made my skin a little red. So I put it away and decided to work on my compromised skin barrier. After 3 weeks of using milder products like cica, I gave this another go. Didn’t irritate my skin this time, but didn’t notice immediate results either. But since I didn’t want to waste it, I used it day and night until I was almost done with the bottle. Then I realized, I hadn’t broken out in months! The few bumpy textured parts on my face are less noticeable. Not sure if this brightened my skin, but no vitamin c I’ve used gave me the brightening effect anyway. This helped improve my overall appearance. I think consistency is the key. I’ve already ordered 3 more when it was on sale.