If You Have Sensitive or Acne-Prone Skin, PHAs Are the Chemical Exfoliant You Need to Know


To the unacquainted, ingredient lists on skincare packaging can look more like a bowl of alphabet soup than read like a recipe for greatness. There’s HA (hyaluronic acid), AHA and BHA (alpha- and beta-hydroxy acids, respectively), vitamin A (retinol), and vitamin C. Recently, however, another less popular string of letters has been appearing on products: PHA, or polyhydroxy acids. 

Like AHAs and BHAs, PHAs are chemical exfoliants. “PHAs are a new generation of exfoliants that are made from gluconolactone and lactobionic acid,” explains Shuting Hu, PhD, cosmetic scientist, and CEO and co-founder of AcadermaTM. “PHAs work by exfoliating dead skin cells on the surface, resulting in a better texture, while also helping to enhance skin cell turnover.” If you’re familiar with chemical exfoliants, you know that’s how they all tend to work. However, PHAs stand apart from AHAs and BHAs because they boast a characteristic that makes them especially ideal for sensitive skin: their molecules are larger.

“The magic of PHAs lies behind their molecular structure and weight,” explains Rita Linkner, MD, a board-certified dermatologist at Spring Street Dermatology℠ in New York City. “They are bigger in size, and therefore can't penetrate to the depth in the skin that their counterparts alpha and beta hydroxy acids can.” Ingredients like glycolic and salicylic acid have a much smaller molecule size, and because they can go deeper into the skin (instead of just staying on the skin’s surface like PHAs), they can be irritating.

So, if you have sensitive skin concerns that have prevented you from using chemical exfoliants in the past, such as rosacea or atopic dermatitis, you may want to seek out PHAs for a gentler experience. Those with blemish-prone complexions may also want to experiment with them. “PHAs are great for use as an acne treatment,” explains Dr. Hu. “They provide hydration benefits to skin without the harshness that can come with AHAs or BHAs.”

Anyone who has experimented with acne treatments in the past knows that they can leave skin feeling parched, and even result in overly flaky skin. PHAs won’t do that: the ingredients actually stick to the surface of the skin, notes Dr. Linkner, acting as humectants and drawing in moisture, not unlike hyaluronic acid. “This strengthens the surface of the skin and protects it from outside elements,” she says.

When shopping for formulas that contain PHAs, it’s worth taking a closer look at the back of the bottle, as PHAs are often paired with powerful (and notoriously sensitizing) ingredients like hydroquinone or retinoic acid. “They counterbalance those caustic effects by protecting and hydrating the surface of the skin, which we derms call the stratum corneum,” adds Dr. Linkner.

Editor's Note

Retinol shouldn't be used by women who are pregnant, considering getting pregnant, or nursing. Please consult with your doctor before use.

Translation: If you’ve ever wanted to dabble with more potent ingredients, but your sensitive skin prevented you from doing so, this is your chance! Using them in tandem with PHA could result in skincare magic. Alternatively, if you’ve ever been afraid to use a chemical peel because of the potential irritation, know you have a viable option that’s less likely to cause any discomfort, redness, or peeling. Plus, with cold weather on its way, we can confidently peel well into winter without concern of flaking or dryness.

Now that you know the powers of PHAs, keep reading — we’ve rounded up a selection of five formulas infused with the stuff that will leave your complexion smooth and glowing without the irritation you might experience from other chemical exfoliants.

The bentonite clay in Ole Henriksen® PHATTM Glow Facial Mask ($49) pulls dirt, oil, and other grime out of pores, while PHAs gently reveal radiant skin after 15 minutes. The addition of Nordic birch sap keeps your complexion feeling hydrated, not parched.

PHAs team up with one of the most iconic exfoliants in the game, retinol, in the Glow Recipe® Avocado Melt Sleeping Mask® ($49). Because the retinol is encapsulated, it is gradually absorbed into the skin over time, rather than instantly, resulting in less irritation than many other vitamin A-infused formulas. Plus, the addition of avocado helps deliver intense nourishment to combat any sensitivity.

The Inkey ListTM Polyhydroxy Acid Toner ($11) may be budget-friendly, but don’t let its low price fool you into thinking it’s low in efficacy. The formula contains a cocktail of three percent PHA to exfoliate, three percent niacinamide to brighten and reduce oil production, and aloe juice to soothe, leaving skin glowing, luminous, and touchably soft.

For a daily moisturizer option, we like COSRX® PHA Moisture Renewal Power CreamTM ($25). It contains three percent PHA to help slough away skin cells, while niacinamide works to keep skin clear, and fifty percent coconut fruit extract delivers a serious splash of hydration.

AHAs, BHAs, and PHAs all join forces in Glossier® Solution ($24), which features a 10 percent concentrated blend of acids to help clarify skin. (It’s also a personal favorite of Dr. Linkner’s!) With daily use, you’ll see smaller, tighter-looking pores, fewer blemishes, and brighter skin. Just be sure to push through the purging period; reviewers claim that there can be a flurry of breakouts once you start the treatment, but they give way to a clear complexion after a week or two.

Some complimentary products were provided to the author for the purpose of writing this article.

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