Tips & Advice

The Difference Between AHAs and BHAs

What are AHAs and BHAs?

AHAs (alpha hydroxy acids) and BHAs (beta hydroxy acid) are both powerful exfoliants that can accelerate cellular turnover by breaking apart the uppermost layers of skin. They are often in products label as “peels” and are used to reduce fine line, wrinkles, and pigmentation.

They also work to treat acne; unclog pores and counteract overproduction of sebum. While both AHAs and BHAs look similar they provide different benefits for different skin concerns.


AHAs are naturally occurring substances found in different fruits, sugar cane, and sour milk. They benefit the outer layer of the skin (the epidermis) and the deep layer of the skin (the dermis). They exfoliate while repairing dry, aging and sun-damaged skin.

AHAs work by loosening the bond that holds together the top layers of dead skin cells and removing excess build up to uncover newer healthier looking skin. They stimulate collagen production which helps to reduce fine lines, wrinkles and the appearance of age spots and skin discoloration.

The most common AHAs are Glycolic Acid, Lactic Acid, and Mandelic Acid. They each provide different benefits for different skin issues.

Glycolic Acid – the most common AHA because it has the smallest molecular size allowing it to penetrate the skin for the deepest repair. This also means it can be the most irritating if your skin is overexposed to it. Start out by using products with less than 10% glycolic acid and work your way up as you’re skin allows.

Lactic Acid – As “Lactic” suggests this is a milk-derived acid which works well at reducing redness in the skin. Lactic Acid is also a milk humectant meaning it holds moisture to your skin, so it can effectively remove the top layer of skin without drying it out.

Mandelic Acid – This has the largest molecular size of these AHAs which allows it to work for a longer period of time without causing as much irritation as a smaller molecule acid. Additionally, Mandelic Acid is also a milk humectant.

Using AHAs in your skin routine help other products to penetrate the skin better, therefore, allowing your skin to get the most out of all your products.


BHAs are oil soluble while AHAs are water soluble only. BHAs are able to get down into the pores to cut through the oil that’s clogging them. They are often used for treating acne because of their antibacterial and anti-inflammatory properties. Rather than just loosening the bonds that bind debris to your skin, they actively penetrate your pores and remove the stuff that’s clogging them. The most common BHA is salicylic acid, which is often found in your acne treating products.

Like AHAs, BHAs also allow your other skincare products to penetrate the skin better. But unlike AHAs, they are not a milk humectant and can very quickly dry out your skin.

Both AHAs and BHAs increase your skin’s sensitivity to light so you should always wear sunscreen with SPF of 15 or higher when using them (but I don’t have to convince you of that because I’m sure you already are wearing a sunscreen with high SPF, right?). I personally just add them into my evening routine to eliminate any increased risk of sun damage.

To use them start with a cleansed and toned face to allow them to work effectively. It’s best to not use them together as they are more likely to cause redness and irritations, so make sure you are using them at different times. Start by adding them to your routine every few days to allow your skin to get used to them. If your skin is handling them well you can add them to your routine more often as you see fit.

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