By Marissa DeSantis
Those in the skincare will already be familiar with chemical exfoliators AHAs and BHAs. But, as it turns out, they aren’t the only acids that can be used to improve everything from skin texture and tone to collagen production. PHAs are creating some buzz, changing how we look at acids with their ability to dissolve the bonds that hold dead skin cells together in a more sensitive skin-friendly way.
Ahead, board-certified dermatologist Dr. Tiffany Libby and aesthetician Tamila Deveny break down the basics of PHAs—from what PHA stands for and what skin types can benefit most from them to how you can incorporate the chemical exfoliant into your skincare routine.
PHAs is short for polyhydroxy acids, and according to Dr. Libby, they belong in the same family tree as alpha hydroxy acids and beta hydroxy acids (think of PHAs as the lesser-known cousin of AHAs and BHAs). Because of this, PHAs provide the same skincare benefits—sloughing away dead skin cells, increasing skin cell turnover, unclogging pores, and reducing the appearance of fine lines and hyperpigmentation.
PHAs go about improving the skin in a less aggressive way than other chemical exfoliators. “PHAs is a larger molecule than AHAs and BHAs,” Dr. Libby explains, noting that because of this, PHAs don’t penetrate as deeply into the skin.
“This allows them to act more superficially and be less irritating.”
Not only does this mean you’re less likely to experience burning and stinging, but Deveny adds that PHAs don’t cause the skin to become as sensitive to the sun (that’s not an invitation to skip out on your daily SPF though!).
As with all skincare ingredients, there is no one-size-fits-all. But the good news is that PHAs tend to work well with more sensitive skin conditions like dryness, eczema, and rosacea. “PHAs are an ideal acid for sensitive skin because they get the job done with less irritation than acids like glycolic or salicylic (AHAs and BHAs),” says Deveny of PHAs ability to create a more even skin tone and texture while providing antioxidant protection and preventing the breakdown of collagen.
Additionally, PHAs allow your moisturizer to work more effectively. “Studies have shown that they have humectant and moisturizing properties, which allow PHAs to retain moisture in the skin barrier while helping to strengthen and repair it,” says Dr. Libby.
Even if this sounds like the perfect solution for you, both experts agree you should ease into using PHAs.
“I advise to test for a reaction behind the ears for 24 to 72 hours,” Deveny suggests.
“Start out by using the product one to two times per week and increase as tolerated to three to four times per week,” Dr. Libby says of all chemical exfoliators. “If you are still sensitive, you can look for products that pair the chemical exfoliating acid with an ingredient that hydrates, rebuilds, and nourishes the skin barrier like ceramides, hyaluronic acid, and glycerin.”
The three most common types of PHAs you’ll see in your skincare products are gluconolactone, galactose, and lactobionic acid. “If you are already using chemical exfoliants, you may already be using a product with PHAs in it, as many products tend to contain a blend of AHAs, BHAs, and PHAs,” Dr. Libby notes. That’s because PHAs are so gentle that they’re able to pair with other chemical exfoliants without causing any additional side effects.
“Alternatively, if you have sensitive skin and can’t tolerate AHAs/BHAs, you may want to opt for a gentler AHA like lactic acid (also a larger molecule with humectant properties) or a PHA-only product,” Dr. Libby advises.