It didn’t happen often, but every time it did it turned the social strata inside out: you’d go back to school after summer vacation, and suddenly, a stranger. A new girl! She just moved from the city (or at least a different suburb with a cooler sounding name), has the platform shoes you’ve been coveting, knows how to tie a cherry stem with her tongue, graciously lends you a bright purple gel pen when your generic black one dies. The whole grade’s obsessed, the cliques shift, and come Thanksgiving no one can remember what life was like before [insert name here] moved to [insert street here]. In skincare right now, that new girl is mandelic acid. Much to lactic acid’s chagrin.

Doesn’t it feel like everyone’s talking about her? She’s popping up in serums, toners, and Instagram Lives… But maybe you two haven’t been acquainted yet. Let us make the intro: mandelic acid is a gentle alpha hydroxy acid derived from almonds. It’s a favorite of the cosmetic chemist duo Victoria Fu and Gloria Lu, as well as board-certified dermatologist. Dr. Lian Mack. “I’ve been using mandelic acid for years!” says the good doc.
Before we do anything else, let’s zoom in. Really far in, even if you don’t have your microscope handy, to look at just one mandelic acid molecule. “Mandelic acid molecules are larger and weigh more than other AHA molecules, including glycolic and lactic acids,” says Dr. Mack. It also has a unique chemical structure (“similar to acne-specialist salicylic acid,” Victoria notes) which allows it to dissolve into the oil clogging your pores. The XL molecules seep into skin slowly, giving this gentle acid its time-release effect. Like dropping little hints before your birthday, it’s an effective way to get exactly what you want without extra irritation.

Returning now to the human-sized world, what does all of that mean for you?

The first takeaway should be that mandelic acid is pretty gentle and tolerable for all skin types. Dr. Mack often recommends it for her rosacea or sensitive skin patients, especially those also dealing with acne. “Many acne regimens are inherently drying and irritating,” she explains, “and choosing mandelic acid reduces the risk of additional irritation while adding the benefit of gentle exfoliation.”

But just because it’s gentle doesn’t mean it can’t get the job done on oily, resilient types. Actually, compared to glycolic and lactic acids, mandelic acid has more available testing data on benefits for oily skin specifically. “That probably explains why it’s been linked to oil and acne claims,” says Victoria, who also notes that some studies have even shown that it helps balance sebum production over time. Gloria adds that many mandelic acid studies test it in conjunction with salicylic acid—for example, when used together in a chemical peel, the combo has been found to meaningfully reduce post-inflammatory hyperpigmentation. For this reason, it’s fairly common to see salicylic and mandelic acids paired together in a skincare product. (Gloria and Victoria do exactly that with their serum, The Specialist, while Dr. Mack is partial towards this toner from the drugstore brand Catrice.) If you do have to choose between salicylic and mandelic acids, the most compelling reason for choosing mandelic is that it’s also antibacterial.

If you have serious acne, the chemists also note that mandelic acid probably won’t replace the classic acne fighters like retinoids, benzoyl peroxide, or dermatologist prescriptions. But, if you are looking to add mandelic acid to your routine, choose a product with at least 2-percent of the active ingredient. That’s the lowest concentration Gloria says will yield results. The upper limit you’ll find over the counter is something in the 10 to 20-percent range, but she doesn’t recommend high concentration formulas for those with very dry skin. Not only can over indexing on AHAs exacerbate dryness, but high levels of mandelic acid are sometimes formulated with correspondingly high levels of drying ethanol alcohol. A chemical peel with mandelic acid can use anywhere from 10 to 45-percent of the stuff.

When incorporating mandelic acid into your routine, treat it exactly the same way you would any exfoliating acid: try to patch-test first, work it in slowly, don’t mix with retinoids at night, and follow with sunscreen in the morning. You’ve got the hang of it! And just like that, you’re on the road to a new best friend.

Mandelic acid treatments to add to your routine:

For breakouts:
Chemist Confessions The Specialist
PCA Skin Acne Gel
Allies of Skin Mandelic Pigmentation Corrector

For evenness:
PSA Heroine Superfood Glow Toner
Stratia Soft Touch AHA
The Ordinary Mandelic Acid 10% + HA

For sensitive softies:
Wishtrend Mandelic Acid Skin Prep Water
Face Reality Mandelic Serum 5%
Catrice Pore 2-in-1 Peeling & Toner

Photo via ITG