So you’ve heard Dr. Belo’s skincare advice: cleanse, tone, exfoliate. (Yep, no moisturizer!) But there’s another crucial step she does that you shouldn’t miss, and it’s the workhorse of your entire skincare routine. Adding a serum ensures that your skin gets the active ingredients you need to improve your specific skin issues, like acne or sun spots.

Dr. Belo personally uses a retinol serum, because it’s fantastic for keeping skin clear and blemish-free. “The number one I’ve been using since I was 11 for acne and also for anti-aging ’cause it’s totally good for everything is retinol, at one percent,” she said at the 2019 Cosmo BeautyCon. But serums of all kinds exist, from natural sources (containing aloe vera or green tea extract) to go-to active ingredients like glycolic acid, Vitamin C, and more. 

(READ: What’s Retinol, And Why Do You Need It in Your Skincare Routine?)

Think of it this way: your serum is the star of your skincare routine. Your makeup remover and cleanser’s only purpose is to rid your skin of dirt and debris. You use toner to balance the pH of your skin….and to get your skin ready to better absorb all the ingredients it’s about to come in contact with. In other words, these steps merely set the stage for the real magic to happen: your serum, which should ideally contain the active ingredient that will take your skin from good to great. Maybe even perfect!

View this post on Instagram

Free radicals can hasten the aging process and cause you to look older and more tired. Take your youth back with the ZO® Daily Power Defense: a powerful antioxidant serum designed to improve the appearance of lines + wrinkles, promote overall skin health, and tighten skin 👊🏼 Tap the photo to shop!

A post shared by Belo Medical Group (@belobeauty) on Sep 10, 2020 at 5:01am PDT

To know which type of serum is right for you, think about the skin issue you want to solve. If you have acne scars or sun spots, Dr. Belo recommends a Vitamin C serum, because it lightens pigmentation. For those who want to get rid of rough skin, niacinamide is your best friend. To fight free radicals and slow down aging, an antioxidant serum does the trick. There are even serums that will address skin laxity and make your skin look firm again. The list goes on and on! You can narrow down your options by speaking with a skin doctor who will prescribe the serum you need.

View this post on Instagram

Reverse the signs of aging with Wrinkle + Texture Repair. 0.5% of high-potency retinol stimulates the skin to support collagen production and refine the skin’s texture. #retinol #antiagingcare #skirenewal #antiagingskincare #skintreatment #skinhealth #antiaging #zoskinhealth #elevateyourskincare

A post shared by ZO® Skin Health (@zoskinhealth) on Sep 15, 2020 at 4:53pm PDT

Your serum is likely to be the most expensive part of your routine. But trust us when we say it’s worth it! The best serums tend to be on the pricier side for a reason—they’re jam-packed with the ingredients your skin badly needs to look and feel its best. Once you see results, you’ll understand why investing in your skin was worth every cent.