Consider This Chemical Exfoliator If You Have Dry or Sensitive Skin

If you’re big into skin care, you’ve most likely tried to incorporate some type of chemical exfoliator into your routine. Think glycolic, salicylic, lactic—these acids fall under the alpha hydroxy acid and beta hydroxy acid umbrellas and are ideal for sloughing off dead skin cells, fighting breakouts, reducing the signs of photo-aging, and smoothing uneven texture. However, these are powerful ingredients which run the risk of disturbing your skin barrier—particularly if you have sensitive skin already—and leading to unwanted irritation (especially during the already dry winter months). So what other options are there if you want the benefits of a chemical exfoliator without wreaking havoc on your skin? May we introduce to you the third and newest hydroxy acid (HA), polyhydroxy acid (PHA).

What’s a PHA, Anyway?

You might be wondering, if HAs can be harmful to those with sensitive skin or particularly dry skin during the winter time, then what makes PHAs different? First, a refresher as to what AHAs and BHAs do. BHAs, or beta-hydroxy acids (like your salicylic acids), are ideal for clearing acne-causing debris, pollution, and excess sebum from pores. That’s why they’re recommended for anyone experiencing comedones or enlarged pores. On the other hand, AHAs, or alpha-hydroxy acids, penetrate the outermost layers of skin, clearing out the oldest dead cells to reveal brighter skin underneath. Glycolic and lactic acid are the skin-care gold standards, but this group also includes malic, tartaric, citric, and mandelic acids.

The third group, PHAs (the most common of which are galactose, lactobionic acid, and gluconolactone), can be considered a less intense version of AHAs. The prefix poly means “many,” and PHAs are essentially like AHAs but with *many* more molecules in their chemical structure. This is important for the way these molecules interact with the skin. “Think of PHAs like a bed of nails, while AHAs are a single nail,” Says Dr. Joshua Zeichner, board-certified dermatologist and director of cosmetic and clinical research in dermatology at Mount Sinai Hospital. “A single nail piercing the skin can cause trauma, [whereas with a bed of nails] the pressure is distributed among the entire bed, so it is much more gentle. Because of their large size, PHAs give effective but gentle exfoliation.”

That larger molecule size also means that PHAs aren’t able to penetrate the skin as deeply, which results in less exfoliation compared to an AHA (and therefore less potential for irritation on sensitive skin). In fact, according to a 2004 clinical trial that examined skin sensitivity of PHAs in comparison to AHAs, “irritation grading and subject self-assessment showed that the PHA regimen was better tolerated than the AHA regimen. Stinging and burning were significantly worse for subjects in the AHA treatment group, and degree of sensitivity was rated worse for the AHA regimen as well.”

The Benefits of PHAs

Other than being what the industry refers to as the gentle giants of the hydroxy acid family, PHAs are also great at moisturizing the skin. According to a 2004 review, “PHAs provide additional humectant and moisturization properties compared with AHAs and can enhance stratum corneum barrier function, therefore increasing the skin’s resistance to chemical challenge.” This is due to the fact that PHAs can attract and bind to large amounts of water in the air and deliver that water to our skin.

Additionally, Dr. Dendy Engelman, board-certified dermatologist practicing at Shafer Clinic, points out, “PHAs have natural antioxidant properties and are great at neutralizing free-radical damage that can be caused from environmental pollutants and/or ultraviolet radiation,” which is a major plus for those of us living in cities or those with active, outdoor lifestyles. Yet their main claim to fame remains their ability to gently slough off dead skin cells, reduce the appearance of fine lines and wrinkles, reduce post-inflammatory hyperpigmentation, smooth texture, and boost radiance.

Who Can Use Them, and When?

Given their chemical composition and gentle exfoliating effects, virtually anyone can use PHAs for a brighter, clearer, and more youthful complexion. According to the aforementioned 2004 review, “PHAs have been found to be compatible with clinically sensitive skin, including rosacea and atopic dermatitis [(eczema)], and can be used after cosmetic procedures.” Furthermore, this hydroxy acid can benefit those with sensitive, blemish-prone skin, helping to clear breakouts and eliminate buildup without aggravating your complexion. Even if you use an AHA toner throughout the spring, summer, and fall, swapping for a gentler PHA might be wise in the winter, when dryness and irritation are more prevalent.

As with any type of exfoliating or cell-renewing ingredient, it’s best to follow the low-and-slow approach when incorporating a PHA into your routine. After determining if this product is suitable for your skin with a 24-hour patch test, we suggest starting with a PHA product three times a week. You can use PHA products morning or night, but we recommend starting with nighttime in order to avoid any unnecessary inflammation during sun exposure. After about a week, you can up your usage to every other day, and after two weeks, you can certainly use a PHA every day if you feel like your skin needs it.

Although PHAs are moisturizing in their nature, we always recommend following this exfoliator with your favorite moisturizer. And as always, there is no effective anti-aging or skin-clearing regimen without proper sun protection, *especially* in exfoliated skin, so make sure to apply your favorite wintertime SPF in the morning and reapply every two hours.

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