Vitamin C serums can seem like an extraneous part of skincare — why do we need vitamin C on our skin along with all the other ingredients our skincare offers? Rest assured, a vitamin C serum isn’t one of those novelty ingredients that works more like a placebo than an effective product. Vitamin C is considered an antioxidant and packs plenty of punch, from fading discoloration, reducing redness, fighting aging through boosting collagen production, to protecting against sun damage.

With all the various benefits that a vitamin C serum can offer, unless your skin is completely perfect and you’re invulnerable to aging and sun damage (if so, drop your skincare routine ASAP), a vitamin C serum is something you’ll want to include in your regiment. Not all serums are created equal, however, and with the massive number of products available, finding the best vitamin C serum can feel like searching for a needle in a haystack. Not to worry, we’ve done the legwork for you and created easy criteria for finding the best vitamin C serum.

Make it Work
Vitamin C serums can come in all sorts of packaging, from droppers to pumps and lotions. Vitamin C is a fragile ingredient that breaks down when exposed to light and air, so the container matters to make sure you’re getting the bang for your buck. Look for airtight containers like pumps and light-blocking containers, like this product from Drunk Elephant.

There are different forms of vitamin C, so check your products to make sure they contain the most stable and impactful version, named ascorbic acid or L-ascorbic acid.

Check the Formula
For oily skin, finding a lighter formula will fit your skin’s needs best, so seek out water-soluble formulas, like this product from Mad Hippie. If your skin could use the extra moisturizing, look for a lipid-soluble instead, like this product from Revision Skincare.

Concentrate on the Numbers
When shopping for your fancy new vitamin C serum, don’t panic over all those annoying percentages. Concentrations can range from 5% to 30%, so it can be confusing to know which strength is right for you, but just keep in mind that 10% is the best place to start.

The concentration you need will depend on your skin type. For sensitive skin, start with a lower level to avoid irritation.

Don’t forget that the way you apply your new serum matters too; serums should be applied after cleansing and before your moisturizer. Wait for about 1 minute before moving on to the next step in your skincare routine so the vitamin C can be absorbed better.