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It’s not every day that a skin-care staple like exfoliating gets an exciting upgrade. But if the hype around polyhydroxy acids (PHAs) is to be believed, we may be ushering in a bright new age of scrubbing dirt and dead skin cells off our faces.
Despite the fact that these compounds were discovered decades ago, they’ve only recently been showing up in products from trendy brands like Glow Recipe, Juice Beauty, and Dr. Jart.
They are supposedly incredibly gentle yet impressively effective chemical exfoliants. So should you add them to your skin-care lineup? We spoke to experts to find out.
What exactly are PHAs?
PHA is short for polyhydroxy acid and there are different chemicals that fall into this category, such as gluconolactone and lactobionic acid, Evan Rieder, M.D., assistant professor in the Ronald O. Perelman department of dermatology at NYU Langone Health, tells SELF.
But the packaging on the front of a skin-care product may just say that it contains PHAs or even just PHA. To figure out exactly which one the product contains you’d you have to read through the full ingredients list.
And even then it may not be obvious. Instead of gluconolactone, for example, the ingredient may be listed as gluconic acid, zinc gluconate, or copper gluconate. (Technically gluconolactone is a sugar alcohol while zinc gluconate is a salt.) They all do basically the same thing when it comes to exfoliation, but the research that exists on these chemicals usually only focuses on one at a time. So it’s important to remember that any conclusions about one compound may not be applicable to another.
The two biggest benefits of using PHAs are that they are chemical exfoliants and humectants, Binh Ngo, M.D., clinical associate professor of dermatology (clinician educator), Keck School of Medicine of USC, tells SELF. That means they can help slough off dead skin cells from the surface of your face and hydrate the skin at the same time, she explains. These properties can be used to manage photodamage, acne, and anti-aging concerns.
Essentially PHAs can be used to gently break down the bonds that hold dead skin cells together, which makes them easy to wash off. Regularly using a chemical exfoliant like PHAs, alpha-hydroxy-acids (AHAs, like lactic acid and glycolic acid), or beta-hydroxy-acids (BHAs, like salicylic acid) may make your skin smoother and glowier, brighten dark spots, and help prevent clogged pores.
However, due to the large molecular structure of PHAs, Dr. Ngo says, they can’t penetrate as deeply into the skin as AHAs or BHAs. Although that sounds like a drawback, it’s actually a good thing for sensitive skin types because it means that PHAs work more gently than other types of chemical exfoliants, Dr. Rieder explains. In fact PHAs are sometimes considered “next-generation” chemical exfoliants because they can do so much with so little irritation.
Research suggests PHAs can do some very helpful things.
In addition to their exfoliating powers, PHAs have some interesting properties when it comes to UV rays. For instance, in a frequently cited 2004 study published in Dermatologic Surgery, researchers found evidence that gluconolactone could prevent some UV-induced damage in mouse skin cells.
These same researchers also looked at the effects of gluconolactone in 11 human participants who applied two lotions to specific areas of their backs six times a day for four weeks. One lotion contained glycolic acid, one contained gluconolactone, and a third designated area didn’t get any lotion. After that time the researchers exposed a 1 cm area of the application sites to a device that simulates UV rays from the sun and then those areas were biopsied. Using the biopsied tissue, the researchers saw that the skin areas where the glycolic acid lotion had been applied showed an increased number of sunburn cells compared to the control area whereas the areas where gluconolactone had been applied did not. The big takeaway here is that gluconolactone in this study didn’t contribute to photosensitivity, Dr. Rieder says, something that’s a known issue with AHAs and BHAs.
Obviously this doesn’t mean that you can skip sunscreen if you’re using a PHA, Dr. Ngo says. Still, if you’re already using a PHA for exfoliating purposes, it’s nice to know you may be spared from some sun-sensitizing effects commonly associated with other chemical exfoliants. And it’s another good sign that PHAs won’t exacerbate sensitive skin the way other chemical exfoliants might, Dr. Ngo adds.
How should you incorporate PHAs into your skin-care routine?
Like other chemical exfoliants, PHAs can still cause some irritation—especially when you first start using them. That’s why Dr. Rieder suggests using a PHA-containing product for the first time on a night where you don’t have anything to do in the morning, juuuust in case you have a bad reaction. From there he says to use it just a few days a week to build up your tolerance until you are able to use it every day.
If you’re already someone who uses other chemical exfoliants, you probably don’t need to add another one. But some products (like Glossier’s Solution, $24) combine PHAs with other exfoliating ingredients so you may be using them already. And Dr. Ngo says those who have especially oily or acne-prone skin could find that PHAs aren’t as effective as other exfoliants. Instead Dr. Rieder suggests they stick with classics like glycolic acid and salicylic acid, which can get deeper into your pores.
But it’s easy to give PHAs a try—they’re present in popular products like Cosrx PHA Moisture Renewal Power Cream, $25; Dr. Jart Dermaclear Micro Milk Peel, $42; PCA Skin Hydrating Serum, $80; Juice Beauty Green Apple Peel, $48; and Glow Recipe Avocado Melt Sleeping Mask, $45. Additionally Dr. Ngo points to Exuviance and Neostrata as more classic PHA-containing brands.
Just be sure to add them into your routine with care and check in with a dermatologist if you notice too much irritation.
All products featured on SELF are independently selected by our editors. If you buy something through our retail links, we may earn an affiliate commission.
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