Whether you have acne, hyperpigmentation, wrinkles, or a dull complexion, there's no product that will have a greater impact on your skin than a serum. "Serums are the most potent type of skincare—they're concentrated and contain the greatest amount of active ingredients," says New York dermatologist Dendy Engelman, MD. "They bring about the most change in your skin. They're made up of small molecules, which allows them to penetrate deeply into the pores for increased efficacy." (Unlike cream moisturizers, which are thicker and reinforce the outer layer of skin, she explains.)
Based on this description, it's easy to understand why serums are the first product that go on clean skin after cleansing or toning. The general rule of thumb, as far as skincare steps go, is this: the thicker the product, the later it should come in your regimen. For example, most dermatologists recommend—in this order—cleansing, toning or exfoliating, applying serum, moisturizer, and finally sunscreen. (Unless you have super oily skin and it's during the summer, serums usually don't take the place of moisturizer, but see how your skin feels after applying the serum and add moisturizer as necessary.) While Engelman says the efficacy of a product won't be diminished if you don't wait a few minutes between each step ("so many products now are formulated to be layered," she says), Los Angeles esthetician Shani Darden prefers to let everything absorb to a certain degree. "Not fully," she says, "but after cleansing, I like to pat the face dry so it's not wet, and then after applying a serum, just wait a little bit to let it absorb."
If you've never used a serum before, getting the hang of applying one might be tricky. Don't use a cloth, cotton ball, or gauze. Just use your fingers, otherwise the product will be absorbed onto the material. Add a few drops to your palms, dot it onto five areas of your face (forehead, each cheek, nose, chin), and then pat or press it into your skin. (Don't rub your palms together before applying it to your face, either, or the product will be absorbed onto your hands.)
Serums not only help reverse skin issues like acne, hyperpigmentation, dullness, and fine lines, but they also prevent future issues from occurring. In the morning, both Darden and Engelman recommend applying an antioxidant-based serum, like Dr. Perricone Cold Plasma Plus Advanced Serum Concentrate. As you go through your day, it will help ward off the harmful and aging effects of pollution and ultraviolet rays. Then, in the evening, find a serum that helps target whatever your pressing skincare issue is. Retinoid-based serums can help with a slew of issues from blemishes to aging and uneven skin tone. Alpha hydroxy acid serums are beneficial for those with pigmentation problems. Salicylic acid serums are also helpful for acne, as they clear the pores, gently exfoliate, and reduce oil production. Depending on the serum you use, you should be able to see a change in your skin in four weeks, Engelman says, but she reminds patients not to give up on a product until eight weeks, as it may take longer to see a difference.
Finding the right serum for your needs requires savvy shopping. "To make sure you're getting an effective serum, look at the ingredient list," Engelman says. "The ingredients listed first contain the highest percentage in a product. Most of the time the first ingredient is water, and then you'll start to see some active ingredients, whether salicylic acid or tocopherol (vitamin E). If you're looking for a serum with a specific ingredient and it's the last one on the list, it won't be a good investment—there's not a high enough concentration in it to make it worth the purchase." A last tip to ensure your serum is effective: active ingredients don't stay active forever. That's why it's important to be regimented with a serum—use it every morning and/or every evening so that you use it up in a timely manner. And, on that note, be sure to store it away from sunlight. Vitamin C, for example, loses potency when exposed to sun.
Trust us on this one—the results of investing in, caring for, and using a serum (or two) will be worth it.