Everything You Need to Know About PHA

what is pha: woman with glowy skin

Acid. The biggest thing to happen to our faces since we all discovered the absolute glow up that is vitamin C, right?

It feels like the entire skin-curious collective has fallen hook, line, and sinker for acid-infused skincare formulas, and that's largely due to the fact that few ingredients can resurface, exfoliate, clarify, and make skin glow quite like them.

If you're properly clued up (and you should be—acids aren't are some serious business), you'll understand that there are a variety of acids that each serve a different role. Sorting your salicylic acid serums from your glycolic acid toners is vital in ensuring you're using an acid that's right for your skin type. But just as we finally understood the difference between AHAs and BHAs (clueless? Don't worry, we'e got a refresher course coming up), a new breed of acid is cropping up on our feeds to present its own set of persuasive benefits: PHAs.

Type of ingredient: Exfoliant

Main benefits: Repairs skin, exfoliates away dead skin, reduces the appearance of skin damage

Who should use it: PHAs are usually safe for all skin types, but especially for those with oily or acne-prone skin. To start, try using PHAs three times a week. You can use it in the form of a toner, a face wash, or even a serum.

Works well with: Other acids in low concentrations.

Don't use with: Other acids in high concentrations, retinoids.

What is PHA?

PHAs, also known as polyhydroxy acids, are the newest acid to take over ingredients lists and news feeds all over the beauty world. They exfoliate on only the surface level of your skin—which isn't always a bad thing, particularly if you're someone whose skin can't handle the level of exfoliation scrubs, AHAs, and BHAs provide. Examples of PHAs include lactobionic acid, gluconolactone, and galactose.

Benefits of PHA

PHAs are a lot gentler on the skin because they have a larger molecule size. That means they take a little longer to properly sink in, and they'll never travel quite as deep as a straight-up AHA. But if you have sensitive skin, that's great news, because you'll probably be able to apply a PHA with little-to-no stinging or irritation. Plus, PHAs are humectants (meaning they retain moisture reserves) and you definitely have a recipe for the most glowing of complexions.

These acids may be best known for their exfoliation properties, but their real claim to fame should be that they come armed with tons of antioxidants and anti-inflammatory properties. An anti-inflammatory exfoliant? Color us excited. They even combat glycation, a process that weakens collagen and elastin in your skin.

AHA vs. BHA vs. PHA

First, you've got your AHAs (alpha-hydroxy acids), and that covers your glycolic, citric, and lactic acids. They all have their own strengths, but they mainly work by nibbling away at skin cells to reveal more glowy skin hiding underneath. AHAs can be pretty intense, so depending on the concentration of your product, you probably want to limit your usage to once or twice a week. As always, start off slow and see how you go.

Then you have your BHAs, or beta-hydroxy acids, which is where salicylic acid can be found. This type of acid is brilliant at flushing out blocked pores, which is why you always hear it recommended for things like acne or keratosis pilaris—that rough skin you have that never quite seems to go away.

And then comes PHAs or poly-hydroxy acids—new-gen AHAs if you will. "They're a special type of AHA that strengthen the skin's barrier function and fight the signs of aging without the irritation of the classic AHA," dermatologist Frances Prenna Jones explains.

Side Effects of PHA

The good news is that PHAs aren't really known for having side effects—that's kind of the whole point. Instead of going deep into your skin, they gently wash away any debris that's sitting on top of it. It's why they're so beloved, and such an easy ingredient to use. However, they are still acids, so if you have sensitive skin, do a patch test.

How to Use It

PHAs are used in a ton of products, and in a few different ways. A lot of AHA solutions will have PHAs in them in order to clean up the surface-level debris AHAs miss. Sometimes, PHAs are added as an extra exfoliating factor to a non-exfoliating product (see Herbivore's Bakuchiol, $54, below) so the dead skin cells are washed away and the properties of the product—usually a serum—can be seen. And sometimes, PHAs are the main selling point.

The Best Products With PHA

what is pha: Lixir Skin Night Switch PHA/AHA 10%
Lixir Night Switch PHA/AHA 10% $28

We were massive fans of Lixir when it first launched (and not only because it's the most Instagrammable brand since Glossier) because it offers pared-back formulas without a load of fluff or filler ingredients. This night serum chips away at the build-up of dead skin cells on the surface, so it is perfect if your skin appears to be wearing a winter coat of dullness.

what is pha: Glossier Solution
Glossier Solution $24

There's a lot going on in this formula, so I wouldn't recommend using it every day—and definitely not if your skin is super sensitive. But it contains a blend of AHAs, BHAs, and PHAs that seem to be having a remarkable effect on clearing up cases of acne. Just go steady.

what is pha: Zelens PHA+ Bio-Peel Resurfacing Facial Pads
Zelens PHA+ Bio-Peel Resurfacing Facial Pads $95

By buffing away layers of dead skin and encouraging skin density, these pads do a great job at making skin look and feel evener. They'll also help lock in water from the atmosphere to amp up that glossy smoothness of supermodel skin.

bakuchiol serum
Herbivore Bakuchiol $54

If you haven't heard of bakuchiol, most of what you need to know is that it's a non-photosensitive, gentler version of a retinol. In this serum—which is safe for even the most sensitive of skin, although you should always do a patch test—it's been combined with PHAs so it doesn't just increase cell turnover, but sloughs off the dead skin that results from it.

dermaclear micro milk peel
Dr. Jart Dermaclear™ Micro Milk Peel $42

If you're looking to PHAs for their gentle qualities, you might want to move past this product, but if you're looking for a full-on exfoliation Dr. Jart has you covered. A powerful combination of AHAs, BHAs, and PHAs makes sure your skin is exfoliated at every level.

low ph pha barrier mist
CosRx Low pH PHA Barrier Mist $21

This barrier-balancing mist from CosRx utilizes the PHA gluconolactone not to exfoliate your face but to protect your skin. The goal of the PHA mist is simple: to keep your skin at the optimal pH for it to stay healthy.

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