AHA’s, BHA’s, PHA’s, WTF?!

You’ve probably heard that exfoliating is good for your skin… or at least we hope so! However, when most people think of exfoliating they picture a physical exfoliant, such as a scrub. But there is actually another form of exfoliant: chemical exfoliants! Specifically AHA’s BHA’s and PHA’s. I know it sounds too scientific but trust us, you probably know a few of them so don’t feel overwhelmed!⁣

The one thing these acid types all have in common is that they are designed to exfoliate the skin, which means they help loosen up the top layer of dead skin cells and allow new, younger skin cells to be revealed. Exfoliants like these are absolutely vital to healthy skin. If you don’t exfoliate 2-3 times a week, dead skin cells will create a kind of blockade not allowing your products to penetrate your skin. If you’re not exfoliating, all your skincare efforts could be going to waste!



AHA, or Alpha Hydroxy Acids, are a group of acids that are naturally found in fruit, milk, sugarcane etc. It is the “first generation” of the acids such as glycolic and lactic acid (see I told you-you would know some). AHA’s can easily penetrate deep into the skin because of their small molecule size. Due to this, these acids help to stimulate our skins’ cell regeneration process, which is perfect for mature skin. They also work well on dry skin (choose a lactic acid as it will help to lock moisture into your skin). However, they are most likely going to be too irritating for someone with sensitive skin.⁣


BHA, or Beta Hydroxy Acids, we predominantly use salicylic acid is the “second generation” of acids. This acid (which can be found in aspirin!) naturally occurs in the white willow tree and contains anti-inflammatory properties. BHA’s are fat soluble which makes it great for oily skin with clogged pores or acne. BHA’s also have very small molecules so they are able to work deeply within your skin to help exfoliate and dissolve oil.⁣


PHA, or Poly Hydroxy Acids are slow working acids such as gluconolactone and lactobionic acids. They have large molecules sizes, and therefore cannot penetrate the skin deeply and only work on the surface. Some might think, what’s the point of that? There are actually a few advantages! These mild acids are perfect for all types of sensitive and/or dry skin conditions such as eczema or rosacea. In addition to this, PHA’s don’t make the skin more photo-sensitive, or susceptible to damaging UV rays.⁣

Can you combine?

This is where it gets a bit fuzzy. Generally, yes you can mix these acids. But we always recommend asking an Esthetician to make sure you are getting the correct combination of acids that are right for your skin. A mixture of all three can easily be too strong for some people.


Acids and the sun

It’s always important to use sunscreen every day regardless if you’re using acids or not. However, it’s especially important to wear SPF while using acids. The exfoliating effect they have on skin makes you more “photosensitive” which just mean more prone to UV damage. You may want to use the bulk of your acids at night and avoid them when on long sunny vacations.

⁣For More Information:

For more information about chemical exfoliants, please contact us at ZONA Med Spa. Or book a complimentary consultation online by clicking here.

Back to the Blog