How to Exfoliate 3: Choosing the Right Exfoliants


Here’s the final part of this series on exfoliation. We’ve looked at all of the physical exfoliants and chemical exfoliants, now we’re turning to the most important question: Which exfoliant should you use? And how often?

Or which exfoliants, rather. Because once you start seeing the results from exfoliating – the glowy skin, the smooth texture, the pigmentation fading – you’ll want to try more. It’s a slippery slope into pretty skin. Unfortunately though, this process can be painstaking and slow, since it takes a while to see the results of any changes in your skincare routine, so have patience!


Guiding Rules

Let’s lay out some guiding principles before we get too excited…

1. Add one new product at a time, a couple of weeks apart

Introducing a whole bunch of skincare products at once is tempting, but a bit of self-control is a good idea. The key reason is that if your skin has a reaction (allergy, irritation, breakouts or just clogged pores), you won’t be able to work out what the culprit is for a while. You’ll have to take everything out, then reintroduce them one by one a couple of weeks apart to check.

Best case scenario? Your skin doesn’t react, it looks amazing, but now you don’t know which of the 5 new products worked. Your skincare routine now takes 3 hours and costs $200 a month.

2. Go slow

This applies to all dimensions of exfoliation. For everything, you need to patch test first if you have sensitive skin. If you have robust skin, you should still patch test first, but I’m the first to admit that I’m too impatient for this most of the time.

In terms of frequency, this means start off with once a week, and if your skin can handle it, then work up gradually.

In terms of harshness for physical exfoliation, start gentle – this means starting with the softest brush, or the finest grains, or pressing gently and scrubbing for only a few seconds.

For chemical exfoliation, this means starting on a lower percentage and working upwards, or starting for a few minutes if it’s a wash-off product, before working up to 10 minutes or whatever the maximum recommended time is.

3. Watch out for overexfoliation

Sensitive, red, tight, weirdly shiny (not in a good way) skin is a hallmark of exfoliating too much, too fast. Your skin needs its protective outer layer, and scrubbing too much off will lead to inflamed, dehydrated skin. If this happens to you, put a hold on all exfoliation until your skin gets back to normal – then let it rest for a few days before going back to exfoliating.

4. Your mileage may vary

This applies to skincare in general. Human skin is all the same to some extent, but it’s still different enough that no product will ever work for everyone the same way. So don’t blindly follow someone on social media who has great skin and scrubs with diamond dust for 5 hours a day – but at the same time, if there’s someone with similar skin concerns as you, and a particular product worked fantastically for them, then it could be a good starting point.

5. Don’t just exfoliate

You should be cleansing before you exfoliate, and moisturising afterwards. Your skincare needs might also change a bit as you exfoliate more regularly.

How to Get Started

Depending on your skincare routine and how well you know your skin, you may be able to skip some of these steps.

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How to Exfoliate 2: All About Chemical Exfoliants


Here’s Part 2 of this skincare series on exfoliation. Part 1 was on physical exfoliating tools and scrubs, this time we’re tackling the more complex chemical exfoliants, before moving onto picking the right exfoliation routine for your skin in Part 3. For a simpler overview, you can head to this exfoliation basics post, and for a more user-friendly version check out my free exfoliation guide.

What’s exfoliation again?

Your skin is covered in a thin protective layer of dead cells (the stratum corneum) which naturally shed over time in a process called desquamation. Sometimes this layer gets too thick, resulting in dull, rough skin. Exfoliants help the shedding along, resulting in more even, “glowier” skin.

What’s chemical exfoliation?

Chemical exfoliants help cells shed in a more indirect way than physical exfoliation, which works using friction between the tool or scrub and the skin. The mechanism of how chemical exfoliants work aren’t always obvious, but the most common theories and methods of how they work are:

  • by normalising cell turnover – that is, how quickly cells in the epidermis die and migrate to the stratum corneum, pushing old cells out. Exfoliants do this by travelling to living cells under the dead layer and telling them to change how they behave – in more technical terms, they act on receptors to upregulate cell division. (Technically, any ingredient that does this is a drug, but regulations around these “cosmeceuticals” is pretty iffy.)
  • by unsticking the cellular glue (desmosomes) holding dead cells together in the stratum corneum.

Chemical exfoliation is touted to be gentler than physical exfoliation, mostly because it’s less prone to user error. However, how well it works depends largely on the formulation of the product. A poorly formulated product might not work, or it might work so well that it irritates your skin and causes uneven pigmentation and chemical burns.

Product categories

Click on each heading to jump to that section.

Leave-on Hydroxy Acid Products

Hydroxy acids are the most common ingredients in chemical exfoliants. There are two main types:

  • Alpha hydroxy acids (AHAs), which includes ingredients like glycolic acid, lactic acid, malic acid and mandelic acid. Glycolic and lactic acids are most common in skincare, and the vast majority of scientific studies on AHAs are based on the action of glycolic acid.
  • Beta hydroxy acids (BHAs), of which salicylic acid is the only one commonly used in skincare (I’ll be using the terms “BHA” and “salicylic acid” interchangeably).

A few ingredients are technically both alpha and beta hydroxy acids such as citric acid, which acts more like an AHA.

It’s not 100% clear how AHAs and BHAs work to exfoliate the skin – it’s likely to be a combination of the two actions described at the beginning: increasing cell turnover at the epidermis and unsticking stratum corneum cells. As well as just removing build-up of skin, they can also improve hyperpigmentation and reduce the appearance of wrinkles.

There are a few key differences between AHAs and BHA/salicylic acid:

  • Solubility: The commonly used AHAs (glycolic acid, lactic acid) are water soluble, while salicylic acid is oil soluble. Theoretically this means salicylic acid is better for treating oily skin and clogged pores because they can penetrate through sebum and sebum plugs, but there’s a lot of variation between people’s experiences. You’ll generally find AHAs in products for dry, ageing skin, and BHA in products for oily, acne-prone skin.
  • Sun sensitivity: Glycolic acid is documented to cause sun sensitivity for a while even after you finish using it, while salicylic acid isn’t. Salicylic acid has a UV protective effect while on the skin, due to the benzene ring in its structure which lets it act as a chemical sunscreen. You need to wear sunscreen while you use alpha hydroxy acids, and for at least a week after you finish – otherwise, you can actually cause more wrinkles and uneven pigmentation and sagginess than you started off with! And you should use sunscreen with salicylic acid anyway.
  • Other effects: Salicylic acid can have some anti-inflammatory action, depending on whether enough gets through the skin – it’s actually one of the active forms of aspirin. Glycolic and lactic acids are humectants that act to slow down the evaporation of water from the skin.

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Fact-check: Why does pH matter for AHAs and BHAs?

Continuing on my pH and hydroxy acid kick, today’s Fact-check is on the influence of pH and alpha and beta hydroxy acids. Hold onto your hats for this one – it gets a bit technical – but hopefully I can translate it to something understandable. Further questions are welcome and I will try to answer them as best I can! …

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Do I need extra sunscreen when using chemical exfoliants? Fact-check Feature

Fact-check Feature is a new series here on Lab Muffin, where I’ll be answering beauty questions and busting beauty myths. Got a question? Email me, or leave me a comment. I’ve heard a lot about sun exposure and chemical exfoliants. What precautions do I need to take? Chemical exfoliants, unlike physical exfoliants, are products that you leave on your skin. …

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Spring Skincare Regimen 1: Cleansers and Serums

I’m guessing this is the case for most beauty junkies, but I tend to think of my skincare routine as simple, but when I actually have to tell someone what’s involved, it turns out to be much more complex than I anticipated! Summer has recently hit Sydney (Sydney doesn’t really have in-between seasons – it was a high of 18 …

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Current Favourites

I haven’t done a favourites post in ages (since New Years in fact!), so I thought I’d share some of my recent finds and classic beauty/shiny favourites: The Grove Perfumery Half Baked – Made by the same people who do Glasshouse, this line is sadly discontinued. Half Baked comes in a cute punk-themed glass with an air-tight lid and smells …

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Is an aspirin mask the same as a beta hydroxy acid treatment?

(Chaval Brasil) Aspirin masks are a popular DIY skincare treatment, but can some pills crushed in water be an effective homemade replacement for expensive salicylic acid exfoliants? Aspirin vs salicylic acid Aspirin is acetylsalicylic acid, which sounds a lot like salicylic acid, a beta hydroxy acid that’s great for exfoliation, with anti-irritant and anti-bacterial properties that make it great for …

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Skincare 101: Exfoliation basics

(Fir0002/Flagstaffotos) Why do I need to exfoliate? Your skin cells are constantly renewing themselves – your entire epidermis (outer skin layers) is replaced every 50 days. Millions of dead skin cells are shed each day from the topmost layer (the stratum corneum) in a natural process called desquamation. However, many things can interfere with this process, such as ageing, hormonal …

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