The 3 most important things a dermatologist says to look for when choosing a serum

If we had a dollar for every time we heard a dermatologist suggest using a serum, we’d be happily retired on a Tahitian beach right about now (covered in SPF, of course). Seriously, in the—very, very—saturated beauty product world, serums remain one of the most important players. And while yes, they technically may not be a bare necessity in the way a cleanser or sunscreen is, they’re essential if you want to incorporate a lot of skin-care ingredients into your complexion (and quick!).

“Serums are unique in that they’re highly concentrated, cosmetically elegant, and easy to layer,” explains board-certified dermatologist Mona Gohara, MD. “This means you only need a little bit to get the benefits of the active ingredients, and you can use it alongside your usual skin care routine without incident.” Not only are they more concentrated, they also penetrate deeper into the skin and are more stable, allowing them to work more effectively than other products. Here’s what to know about using one that’s packed with vitamin C, straight from Dr. Gohara:

“Serums deliver active ingredients past the superficial layer of the epidermis and are usually fat-based, which helps stabilize and preserve the important ingredients until they can be absorbed by the skin,” says Sheel Desai Solomon, MD, FAAD, a dermatologist in North Carolina. A quick note on application: Because they’re so light, serums should go directly onto clean skin, before any other products. The only drawback? There are so. many. freaking. choices. Variety may be the spice of life, but it can make serum shopping overwhelming to say the least. To aid you in your search, we asked Dr. Gohara and Dr. Solomon to weigh in on what’s most important to look for when choosing a serum. Here are the three most important things, according to them.

The active ingredient

Consider your complexion concerns and goals and focus on finding a serum with an active ingredient that will target those needs specifically. “Look for serums that have an ingredient you know you’ll get a big benefit from,” suggests Gohara. A few examples—retinol for wrinkles, hyaluronic acid for dryness, or vitamin C for brightening. Not quite sure what you need? When in doubt, opt for an antioxidant serum. The universal go-to for any and all skin types, these combat free radicals, addressing the signs of aging and generally improving your skin’s health, says Solomon. For the best results, layer one under sunscreen every morning; it will act as a second line of defense against free radical damage caused by exposure to UV rays. Here’s what to know about retinol, BTW:

Extra hydrating ingredients

Once you’ve pinpointed your primary player, look for a few supporting—hydrating—actors that will complement the star of the show. More specifically, look for ingredients that mimic the natural moisturizers found in our skin, such as ceramides, amino acids, and fatty acids. While these are found in all kinds of beauty products, using them in a serum will help ensure they get deeper into the skin further improve the benefits, notes Dr. Solomon.

The price

The variety of serum options also comes at a variety of price points. And while we’re certainly not saying that there aren’t great, affordable options out there, this is a smart place to spend more money. “Serums are where you should splurge. A small bit each day can do wonders for your complexion, and they’re one of the most reliable skincare products out there in terms of efficacy,” says Dr. Gohara. So there you have it: Follow these three easy steps to finding your perfect skin care serum regimen ASAP.

Ok, here’s how to use a hyaluronic acid serum if that’s one that you want to incorporate or you could try an algae-spiked serum for some hydrating love.