These Vitamin C Serums Are the Ultimate Pick-Me-Up for Dull Skin

There are a whole lot of serums out there, from eyelash serum to hyaluronic acid serum to anti-aging face serum. But what if you only have room in your makeup bag for one? Experts say to go with a vitamin C serum—because it really works. "Vitamin C is a powerful antioxidant that fights fine lines by stimulating collagen, brightens your complexion by blocking excess pigment creation, and protects your skin from damaging free radical and other environmental stressors," says Dr. Michelle Henry, clinical instructor of dermatology at Weill Cornell Medical College. "As we age, though, the skin's natural levels of antioxidant vitamin C decrease, which is why it's so important to add it to your skincare routine." The one downside? Compared to most products, it often costs more per ounce.

To make sure you get the best return on your investment, here are a few things to keep in mind: Skip creams spiked with vitamin C and instead choose a serum, which is more effective at penetrating the skin barrier, says Dr. Brooke Jackson, a board-certified dermatologist in Durham, North Carolina. Additionally, there are several forms of vitamin C—and not all are created equal, says Henry. Check the label for L-ascorbic acid, which is considered to be the vitamin C best for skin. (Even better: If it contains 15 to 20 percent L-ascorbic acid, which is the most effective.) "Vitamin C is notoriously unstable—especially when it's exposed to air and light," says Jackson. "So it's best to pick a formula that comes in an airtight pump or opaque bottle, and keep it away from direct sunlight." Plus, once you begin to see the results of a good vitamin C serum, you can use less primer, less foundation, and less highlighter, ultimately saving you money.

So, which ones are worth it? These face brightening and tightening formulas—suitable for a wide range of skin types, including acne-prone, hyperpigmentation, oily, dry and sensitive skin—are the best vitamin C serums money can buy.