Vitamin C Serum
Why: Whether you accidentally got burned on your BFF's bachelorette in Puerto Rico or from your high-school preprom tanning session, you need to reverse UV damage and sun spots with a brightening vitamin C-infused serum. The rock-star ingredient is rich in antioxidants to detox skin.
Try: Ever since I got my first vitamin C facial at NYC spa Mario Badescu, I've been hooked on the take-home treatment: Vitamin C Serum ($45). It's potent with a 7.5-percent ascorbic acid formula, so make sure to only use it every other night, since it's too strong for everyday use and daytime light exposure can tamper with the results.