How To Navigate Exfoliating Serums For Your Brightest Skin Ever

This time two years ago, my acne-prone skin was smoother, clearer, and more radiant than ever. The secret: A dermatologist in Seoul, South Korea, jabbed my face about 300 times with skin booster shots aka injectables spiked with hyaluronic acid, amino acids, and vitamins A, B, C, and E. With travel back to Korea off the table at the moment, I’ve found a painless — and much more affordable — alternative to get my complexion glowing just as bright in the form of exfoliating serums.

Luckily, stateside beauty shelves are becoming fully decked out with amazing exfoliating serum choices from brands like Herbivore, Typology, and The Ordinary. K-beauty imports have also made their way over to America from the likes of Dr. Jart+ and Peach & Lily. The dizzying amount of options tout confusing abbreviations for the uninitiated, such as AHAs, BHAs, PHAs. What do they all mean? Which one should you shop for? Well, I’ve got just the answers for you.

I asked board-certified dermatologists and cosmetic chemists to share their expert insight on the growing skin care product category. Below, they’ll break down their versatile benefits, who exactly should factor exfoliating serums into their routines, and what step to slot them in for. You’ll also learn what doesn’t mix well with the acid-based elixirs. Let’s start with the basics.

What Exactly Is An Exfoliating Serum?

To put it simply, it’s a serum spiked with acids known to chemically exfoliate skin by helping unstick dead skin cells from the surface of your face. Although “our skin naturally sheds [them], this process sometimes slows down with changing weather and advancing age,” explains cosmetic chemist Michelle Wong.

With the powers of alpha hydroxy acids (AHAs), such as lactic acid, glycolic acid, mandelic acid; beta hydroxy acids (BHA), like salicylic acid; and poly hydroxy acid (PHA), including gluconolactone, galactose, and lactobionic acid, exfoliating serums speed up the process, shares Dr. David Kim, a board-certified dermatologist based in New York City. Plus, this product category “tends to have higher percentages of [these] acids, so they’re more effective than scrubs or toners,” he adds.

Unlike face scrubs, these serums don’t rely on physical force and rinsing to buff away dull, flaky skin, Wong says. Exfoliating serums, instead, loosen the bonds between dead skin cells on the surface of your face to gently slough them away and gradually smooth skin, explains Dr. Aegean Chan, a board-certified dermatologist in Santa Barbara, California.

Plus, serums tend to have a lower viscosity, so their active ingredients can penetrate skin more easily than products with thicker consistencies, namely moisturizer, Chan points out.

Personally, I prefer going for an exfoliating serum over an exfoliating toner, treatment, or mask because they are easiest to apply with just your fingertips, and I can focus on deeply hydrating my skin with the other steps of my skin care routine.

Which Skin Concerns Do Exfoliating Serums Address?

Among the long list of benefits exfoliating serums tout, you may have gathered by now that brightening and smoothing dull, textured skin is their top priority. The powerful skin care product also helps even out skin tone by decreasing the appearance of hyperpigmentation due to acne, sun damage, and melasma, Chan says.

But that’s not all: “They can also help with acne by unclogging pores and regulating sebum production,” Kim says. “They all increase cellular turnover and help with fine lines and wrinkles as well.”

Do Certain Acids Work Better For Specific Skin Types?

Absolutely. Here’s an easy guide to keep in mind when shopping for an exfoliating serum:

• Sensitive skin: PHAs and lactic acid
• Oily and acne-prone skin: BHAs and glycolic acid
• Mature skin: AHAs
• Deeper skin tones: Mandelic acid

PHAs

Because PHAs are the gentlest and least irritating of all the acid families, Kim suggests them for sensitive skin.

We only include products that have been independently selected by TZR's editorial team. However, we may receive a portion of sales if you purchase a product through a link in this article.

Lactic Acid

This is also another amazing, low-key option because like PHAs, lactic acid has larger particles with less skin penetration, Chan adds. It also is known to have moisturizing properties, which help minimize inflammation. Throughout her pregnancy, Chan reached for The Ordinary’s Lactic Acid 5% + HA Serum. Personally, I’ve been into the Monday Born Beauty Rebirth Exfoliating Serum, as well as the Peach & Lily Power Cocktail Lactic Acid Repair Serum lately. Even though the latter is loaded with double the percentage of lactic acid, it never stings or leaves my finicky skin red and angry.

BHAs

These on the other hand, are lipophilic, meaning they dissolve in oil, so they target oil glands specifically, Kim says, which makes them great for anyone dealing with breakouts. About 1.5% BHA is the star of the Cocokind Probiotic Serum via blemish-busting salicylic acid.

Glycolic Acid

This AHA can also unclog pores for those with acne-prone skin. As New York City-based dermatologist Dr. Dendy Engleman previously told TZR, it has the smallest-sized acid particles, so it can most effectively plunge deeply into pores to clear them out. The Typology Exfoliating Serum 10% Glycolic Acid is an amazing option as the high percentage is accompanied by calming ingredients, like chamomile and mastic gum.

AHAs

In general, AHAs target hyperpigmentation, fine lines, and wrinkles best, according to dermatologists. Unlike BHAs, AHAs are water-soluble, so they do their best work on the surface of the skin instead of diving into the pits of your pores, as Dr. Hadley King, a New York City-based board-certified dermatologist, previously shared with TZR.

Mandelic Acid

For those with deeper complexions, mandelic acid, an AHA, is your best bet. According to cosmetic biochemist Krupa Koestline, several studies have shown it's the go-to acid for hyperpigmentation on darker skin tones due to its low pKa value compared to others. In other words, it's less irritating, so it has less of a chance to exasperate discoloration and acne scarring. The Youth to the People Mandelic Acid + Superfood Unity Exfoliant and Vivant 8% Mandelic Acid 3-in-1 Serum are excellent product picks in this case.

Who Should Avoid Exfoliating Serums?

Although sensitive skin types can tolerate PHAs, the dermatologists I interviewed both recommended proceeding with caution when slathering on exfoliating serums. “I would be careful and start introducing it to your skin care routine slowly by using it once a week or every other week,” Kim says. If you have eczema or rosacea, though, Chan says you should avoid exfoliating serums entirely.

Avid retinol users should steer clear of layering on exfoliating serums at the same time as their vitamin A product of choice to avoid overwhelming and over-exfoliating your skin, Kim says. Personally, I like to follow Dr. Whitney Bowe’s “skin cycle.” The New York City-based dermatologist recommends this easy-to-remember routine to her patients:

• Night 1: Exfoliating serum
• Night 2: Retinol
• Nights 3 and 4: Neither; just fragrance-free moisturizer
• Night 5: Start again

Those who are devoted to vitamin C serums can keep their favorite in their morning regimen, and the exfoliating serum of your choice can be relegated to nighttime use for optimal hyperpigmentation-diminishing results, Chan says.

And last but not least, Kim warns against adding an exfoliating serum to your skin care routine if your skin is dry and dehydrated, especially during the winter and while in chilly cities, to keep your skin from flaring up. Instead, summertime and hotter locales are prime for them. “When it's humid, the skin may be able to tolerate [exfoliating serums] better,” he says.

How Should You Implement Exfoliating Serums Into Your Skin Care Routine?

Once you’ve found the right exfoliating serum for your product lineup, Kim recommends adding it to your nighttime skin care routine to let the acids work their magic overnight uninterrupted — even if you aren’t an aforementioned vitamin C person. From there, you should slot the serum in after cleansing steps and before moisturizing, says Chan.

The frequency of use depends on your skin type and the percentage of acids, according to Kim and Chan. Be sure to read the serum’s label to find out what the brand recommends. However, starting off with once-a-week use will help you gauge how well your skin can tolerate the acids. Also, higher-strength acids over the 10% range should only be used two or three times a week. “Daily use may lead to excess skin barrier damage and skin irritation,” Chan says.

Most of all, remember to stick to one acid-infused product per regimen to avoid over-exfoliation, which can dry out skin, as well as cause major damage and irritation. “When you use too many exfoliants, you can thin out your dead skin cells too much,” Wong says. “The layer of dead skin cells, known as the stratum corneum, is important in forming a barrier against the outside world. This keeps irritants out of your skin while sealing water in.”

If you desire something stronger or deeper, consider seeking out an in-office chemical peel, Kim says. And be sure to wear SPF every day as these acids make skin much more sensitive to the sun than usual.