Your Guide To Polyhydroxy Acids (PHA) In Skincare


If you’re particularly into skin care, then your likely already exfoliating with alpha hydroxy acids and beta hydroxy acids but over the past year another three-letter acronym has been all the rage: PHAs.

But what are they, and how do they differ from their alpha- and beta- counterparts?

So, what are PHAs?

Polyhydroxy acids (PHAs) are chemical exfoliants just like BHA’s and AHA’s. The most common PHAs in skincare are gluconolactone, galactose, and lactobionic acid.

Similar to AHAs, PHAs work by exfoliating dead skin cells on the surface, resulting in a more even skin tone and texture. They also help skin-care ingredients penetrate deeper into the layers of your skin, thus boosting their efficacy.

Which skin types benefit the most from PHAs?

Sensitive skin types may benefit best from PHAs. The unique properties of PHAs, including it’s larger molecule size and surface level penetration, make them ideal for virtually all skin types but especially if you’ve experienced sensitivity in the past with an AHA- or BHA-based product.

Additionally, PHAs are an attractive option for those with dry skin as they are humectants, meaning they attract water and are ultimately moisturizing.

As PHAs are the most gentle of all the hydroxy acids, even eczema or atopic rosacea prone skin types can benefit/try PHAs to help smooth and retexturize skin without irritation with a product like Exuviance’s Moisture Balance Toner.

How are PHAs different from AHAs and BHAs?

AHAs, such as glycolic acid and lactic acid, penetrate the skin more deeply, while BHAs like salicylic acid are better suited to oilier, acne-prone skin. These characteristics are down to their size. BHA’s are more suited to acne-prone skin because they are bigger and don’t penetrate the skin as deeply, therefore causing less irritation.

Well, the molecules of PHAs are even larger and therefore cannot penetrate as deeply as both AHAs and BHAs; they work exclusively on the surface, without disturbing the deeper delicate layers. This means that they are perfect for treating very sensitive skin.

Can BHAs, AHAs and PHAs be mixed together?

Yes, it can be done in fact many brands have already done this! You may have noticed products like Glossier’s Solution contain’s a cocktail of exfoliating AHAs, BHAs, and PHAs in one bottle. 

However, this does mean that PHAs gentleness will be dissolved by the other active ingredients that will irritate your skin if you are prone to irritation by AHAs and BHAs. If that’s a little strong for your skin, try taking things slow with a PHA-based product, like Neostrata’s Bionic Face Cream.

Are PHA’s good for anti-aging?

Yes they are excellent for anti-aging. Infact, there have been numerous clinical studies conducted to evaluate the benefits of PHA’s in skincare and significant evidence found that PHAs provide anti-aging effects to the skin.

One study showed a relative equivalence of AHAs and PHAs in treating photaged skin which is amazing news for those of you who can’t use AHAs. If you can use AHAs something like these Zelens PHA+ Bio-Peel Resurfacing Facial Pads are a great way to combat fine lines, dullness, and enlarged pores as they have a combination of AHAs and PHAs in it.

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