Your Complete Guide to AHA/BHAs

Exfoliation is part of any successful skincare routine and is a skin game changer if you don’t already do it. Daily, our skin combats pollution, makeup, oil, and the natural aging process. Exfoliating removes dead skin cell build-up which helps relieve rough, dry, or dull skin. There are two types of exfoliation, manual or chemical, and each provides smoother, brighter skin to various degrees. Manual exfoliants generally contain gritty particles which resurface the outer layer of your skin and are great options for a quick fix. Chemical exfoliation, however, tends to provide more effective results. 

Acids, in general, are used for exfoliation and rejuvenation, but certain types can help you target a more specific skin concern. Knowing what active ingredients to look for ensures that your dollars are spent on products that actually work. 


First off, what does AHA or BHA mean? They’re both acids but with different chemical structures. The differences are important because they change the way that the acids will affect your skin. 

 AHA stands for alpha hydroxy acids and BHA for beta hydroxy acid. 

The main difference between the two is that AHAs are water-soluble (dissolves in water) and BHAs are oil soluble (dissolves in oil). Because of this, AHAs loosens the bonds between the top layer of your skin cells while BHAs can push past the oil to scrub your pores and purge debris and sebum. 

They exhibit mostly similar skin-renewing benefits by causing controlled damage to help increase cellular rejuvenation but different enough to be able to help targeted areas of concern. 


Lactic acid, derived from milk and other foods, (and yes, the same one that builds up in your muscles when you work out really hard) is a naturally occurring compound that when produced synthetically can have amazing benefits for your skin. 

Lactic acid, an AHA, is a favorite for sensitive or mature skin types. Because this acid has a larger molecule size it’s not able to penetrate as deeply into the skin which means there’s less chance for irritation or burning. 

It works to breakdown the bonding between skin cells which helps to gently exfoliate and slough away dull, dead skin. Lactic allows for a more polished, hydrated, and firmer skin tone. Because it targets a surface layer of the skin, it is ideal for those looking to reduce issues such as pigmentation irregularities like freckles, sun spots, or darkened acne scars. 

Lactic acid is unique in that it improves the skin’s natural moisture barrier. It is a natural humectant, which means it pulls water into the skin and helps retain a healthy, supple moisture level in the skin. Additionally,  as the acid exfoliates it provides a better base for other hydrating ingredients to be absorbed and trapped in the skin. 


Glycolic acid makes an appearance in many different skincare products, and for good reason. This acid is a powerhouse anti-aging ingredient that touts wrinkle-reducing and line smoothing benefits. 

It’s a natural fruit acid derived from sugarcane and of the AHAs, it has the smallest molecular size of the AHAs which allows for maximum penetration. It’s best for targeting wrinkles, lines, and improving texture issues. It works deep within the skin to enhance collagen and elastin regeneration which leads to an overall more youthful appearance. It’s important to note that because it is able to penetrate deeply that it can potentially cause irritation if you go overboard. Opt for lower concentrations and build-up use as your skin adjusts. 

Glycolic is ideal for really any age (prevention is key!) and aids in cellular turnover to achieve that coveted glow. 


Salicylic acid is part of the BHA family and is a well-known acne zapper. It’s naturally occurring from the bark of willow trees. 

Salicylic acid differs from the AHAs as it is oil-soluble, meaning that it is able to penetrate through oil and breakdown the sebum and congestion in your pores. In addition to creating a breathable pore environment, it is anti-inflammatory and helps reduce redness and puffiness. 

This acid is ideal for skin types struggling with acne, oiliness, and whiteheads/blackheads. You can commonly find it in over the counter acne treatments at a 2% concentration. Higher concentrations are used in the peels for a much more effective treatment. 

And if you’re one of the lucky ones that don’t struggle frequently with acne, it still has a great overall toning and brightening effects along with its anti-inflammatory properties. 


Trichloroacetic acid is a derivative of acetic acid (vinegar). 

Used for acne scars, pigment correction, and texture issues it is a medium depth peel that penetrates deeper into the skin than the aforementioned peels. 

It’s best suited for those with advanced hyperpigmentation or deeper lines as it damages a deeper layer of the skin for renewed and refreshed skin texture. If you do a TCA peel at home it’s vital to remember that you need to start slow. Because it’s able to get into the deeper dermal layers of your skin, you don’t want to overdo it because you can risk burning or scarring yourself. 

A slow and timed application can help you get the most out of the peel. TCA peels of higher concentrations should be administered by a professional. 

How to use it:

Each of these ingredients can be found in various products and concentrations. They’re often added to lotions and creams at a lower concentration for gentle, daily use. They are used in higher concentrations for their exfoliating and brightening properties in various cleansers, peels (at-home or dermatologist administered), or toners. 

All of the acids cause photosensitivity because as you slough away old skin the newer skin will be much more sensitive to sunlight. Because it is fresh it can be more prone to damage. Diligent SPF use is a must, and avoiding sun exposure for a few weeks after peeling is ideal, especially if it was a deeper peel. 

It’s important to incorporate the acids slowly at first and to try a patch test to make sure you’re not allergic to anything. Though some acids are gentler than others, it’s important to note that any acid can be irritating if used too frequently or at too high a concentration. With chemical peels, patience is extremely important. 

Starting slow will prevent burning or excessive irritation. Frequent use of acids with other active ingredients, such as retinol or other acids, can also cause dryness, flaking, or sensitivity. Starting with lower concentrations and with spaced use will allow for your skin to adjust to the new products. 

Exfoliation is a must for healthy, glowing skin. Adding in a chemical exfoliant can drastically help with continued use, and there are a plethora of options and products to choose from. 

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