This is one of my HOLY GRAIL products!! I love the way it smooths my skin and clears/prevents acne bumps with regular use. I started using it every other day at first and mixing 2-3 drops in my moisturizer or with another serum. It can take some getting used to but I now use it every night and my skin has never been smoother and clearer. Also, the price is AMAZING for what it does!!!
Absolutely nothing! I guess if you have sensitive skin, use it every few days at first until your skin adapts. Other than that, it's perfect!!