Guide to chemical exfoliants: What are they, how to use them and how much is too much?


By Redzhanna Jazmin

Guide to chemical exfoliants: What are they, how to use them and how much is too much?

Alright, skincare enthusiasts—today we’re talking exfoliants. Specifically, exfoliants of the chemical kind. An often misused and intimidating ingredient, we’ve taken the opportunity to show you how to make the most of them, maximising their benefits and troubleshooting some common issues.

From how often to use them, to the best chemical exfoliant for each skin type, this tell-all guide is your one-stop shop for any and all of your burning questions.

What are chemical exfoliants?

There are three types: AHAs, BHAs and PHAs (we’re not getting into enzymes…yet).


Alpha Hydroxy Acids are tiny water-soluble molecules that are able to dissolve the intercellular glue holding your superficial skin cells together, which thus promotes your skin’s natural shedding process. In addition, they also stimulate collagen production in the skin to improve skin elasticity and moisture content.

As they are lipophobic (oil-repellent), their action is mainly focused on the surface of the skin, so they do not penetrate as deeply as BHAs do.

In addition, they can improve the moisture content of your skin, which makes them perfect for an array of skin types (we’ll get to that later). They are also derived from natural sources; here are a few AHAs you may be familiar with:

AHA Source
Glycolic acid Sugar cane
Lactic acid Milk
Mandelic acid Bitter almonds
Tartaric acid Grapes
Malic acid Apples and pears
Citric acid Citrus fruits

Note: Citric acid and malic acid can behave like either AHAs or a BHAs, depending on how it is formulated. However, they act as AHAs more often.


Beta Hydroxy Acids are oil-soluble, meaning that they penetrate deeper into your skin as they can get through the sebaceous oil in clogged pores. They act to gently push out dead skin, bacteria, sebum and other pore-clogging debris. In addition, they also have many anti-inflammatory and anti-bacterial properties, which makes them suited for an array of particular skin types.

You’re probably familiar with one particular BHA: Salicylic acid. It’s one of the most ubiquitous ingredients, found in all types of spot creams, toners and other cosmetics.


Much lesser known, but also the most gentle of all chemical exfoliants, Polyhydroxy Acids are the holy grail for all sensitive skin types (including conditions such as eczema or rosacea). They work in the same way as AHAs do, only slower and less penetrating (because their molecules are larger). PHAs, like AHAs, are humectants, so they attract moisture to improve skin hydration.

Like BHAs, they also have anti-bacterial and anti-inflammatory properties. Some examples of PHAs that you may have encountered are gluconolactone, galactose and lactobionic acid.

Why do I need to exfoliate?

Exfoliation (when done right) is a great way to restore skin health by promoting cell turnover and blood flow. Plus, removing that layer of dead skin cells improves the absorption of the rest of your beauty products by your skin.

Your skin is made up of many, many layers; and the outermost of it is called the Stratum corneum of the epidermis. It is a resilient layer of keratinised cells that shed regularly to balance out skin cell production. It has a bunch of physiological functions, including protecting the underlying tissue from dehydration and infection. Its thickness varies throughout the body, with the thickest areas being on the feet and hands (naturally) and the thinnest being in areas such as the face.

Fun fact: when your skin looks dull, it’s because your Stratum corneum has thickened too much, warranting a much-needed exfoliation session.

Which one should I use?

It all comes down to skin type. Here’s a nifty little guide to help you figure out what will work best for you.

That said, a lot of chemical exfoliants on the market are different blends of acids; for example, Drunk Elephant’s TLC Framboos Glycolic Night Serum and Dr Dennis Gross’ Alpha Beta Extra Strength Daily Peel are both blends of AHAs and BHAs. The key is to scan the ingredients list before you buy and make sure that it suits your skin!

Is there anything I shouldn’t use with my chemical exfoliant?

It’s always imperative to check the ingredients in your skincare products! Look out for Retinoids, Vitamin C and benzoyl peroxide as these can all interact badly with your chemical exfoliants.

Why do I need SPF?

It’s true—there has been no evidence (so far) to suggest that BHAs like salicylic acid have any photosensitisation effects on skin after use. Interestingly, it was actually shown to have protective effects on the skin from UVB rays. In fact, some derivatives of salicylic acid such as octyl salicylate are common ingredients in sunscreen, that help to absorb UV light and prevent skin damage.

That said, with AHAs, it’s a different story. Think about it this way: you’re putting a product on your skin that essentially strips your skin of it’s topmost protective layer. Yes, it doesn’t get rid of the whole layer (otherwise, ouch) but studies (of which there are a very limited number, to be fair) have shown that AHAs increased skin photosensitivity. Specifically, the results found that UV exposure 24 hours after AHA application caused symptoms of increased redness, DNA damage and sunburn cell production in human skin.

Either way, regardless of whether you’re using chemical exfoliants or not, it’s always a good idea to stay on the safe side and layer up on the sunscreen–especially in Malaysia’s eternal summer.

How much is too much?

As good as silky smooth skin can feel post-treatment, it’s easy to get carried away and go overboard. Yes, over-exfoliation is a real thing. You’ll know that you’ve gone a little bit too far when you start experiencing a few of these things:

At this point, you’re going to want to cut way, way back on the exfoliation, and focus more on hydration. Also, skip the foaming cleansers—your already dehydrated skin doesn’t need anything else sucking the moisture out of it. Instead, opt for cleansing lotions, which are far more gentle on the skin, and opt for moisturisers that are fragrance-free and alcohol-free.

You can introduce exfoliation back into your routine again once your skin is recovered; just make sure that you’re doing so gradually, sticking to once every fortnight and slowly increasing the frequency to three times a week at most.

So, there you have it! All your questions about chemical exfoliants: answered.

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