An introduction to acid exfoliants. There is so much information out there regarding acids from AHAs to BHAs and questions as to whether you need an acid in your routine and how strong? It is quite a complex issue because there are so many different options and everyone’s skin may need something slightly different.
My aim with this introductory guide is to give you the facts. An uncomplicated, simple guide so that you can gain the confidence to go away and explore what acid exfoliants may work best for you.
Both AHAs and BHAs are chemical acid exfoliants. They both have slightly different mechanisms but overall, they both work to shed dead skin cells from the surface layer of your skin. This then reveals the fresh layer of skin underneath. AHAs and BHAs both have hydrating properties, help fade pigmentation and are the most commonly used acids for chemical exfoliation.
AHAs vs BHAs vs PHAs
Alpha-hydroxy acids (AHAs) are water soluble and work on the surface layer of the skin. This means that they don’t really have an action on sebum or oil as this is deeper within the pores.
Types of AHAs you’ll find in skincare:
Glycolic acid (derived from sugar cane) is the most popular AHA. However, it’s also the most aggressive as it has a very small molecular size.
Lactic acid (derived from milk) which is a little gentler and more easily tolerated by skins.
Mandelic acid (derived from bitter almonds) is also quite gentle. It’s often one you’ll find combined with other acids in a formulation.
Malic acid (derived from apples) is another gentler alternative to glycolic. You’ll see this in blended formulations too alongside citric acid (which, you guessed it, is derived from citrus fruit).
Tartaric acid (derived from grapes) is another acid ingredient gaining popularity but it’s worth noting that this doesn’t always act as an exfoliant but is used to stabilize the pH of other acids in a formulation.
Poly-hydroxy acids (PHAs) are second generation AHAs which have a bigger molecular size so they are gentler and act like humectants. I’m a big fan of PHAs. One of the most common ones is gluconolactone.
Beta-hydroxy acids (BHAs) are oil soluble so it can actually penetrate the inside of the pore and regulate sebum production clearing out excess oil. It also helps regulate cell turnover. The most popular one is salicylic acid which is also an anti-inflammatory. Willow bark extract is another BHA that’s less commonly used.
Which Type of Acid is Right For You?
Generally speaking, if your skin issues fall into the categories of open pores, oiliness and breakouts then choose a BHA.
If your skin issues are pigmentation, wrinkles and sun damage I would choose an AHA. The one you pick should be based on your skin sensitivity. For example if your skin is dry and sensitive I would choose lactic acid or a PHA.
There are also formulations that include a combination of AHAs and BHAs. These are great if you’re looking to tackle several skin issues at once. Remember, most acids work on similar functions (i.e smoothing and brightening the skin).
Remember: Any acid used in the wrong concentration or too frequently can cause irritation, inflammation and dryness. So you really need to be mindful of what your skin needs and how it reacts to products. Just because it says you can use something daily on the packaging doesn’t mean you have to or that your skin will appreciate it. Ease yourself into using acids.
Remember: Always wear sunscreen (this is a golden rule regardless) because AHAs are photosensitive. If you struggle with skin sensitivity then use your BHA in the morning and AHA at night so you don’t run the risk of creating additional inflammation due to UV exposure.
My Favourite Acid Exfoliants
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BHA’s – I love the Cosrx Blackhead Power Liquid* which contains willow bark and niacinamide alongside a form of hyaluronic acid. As well as the Paula’s Choice 2% BHA Liquid Exfoliant* which contains salicylic acid.
AHA’s – My favourites tend to be blends. A strong one is the Estee Lauder Perfectionist Pro Instant Resurfacing Peel* which contains glycolic acid so is quite potent. I also love the Allies of Skin Pigmentation Corrector Night Serum* which has a blend of acids with mandelic being the star. The Biossance Resurfacing Night Serum* is great because you’ve got gentle lactic acid exfoliation alongside squalane to further nourish the skin.
My Alex Steinherr x Primark Pollution Solution Pads are a blend of lactic acid and a PHA so they’re super gentle and good if you’re a beginner with including acids in your routine. Another gentle lactic acid blend that’s good for pigmentation is the Elemis Peptide4 Overnight Radiance Peel which I’ve written a whole post about. Finally, we’ve got the QMS Active Exfoliant* which is a mega blend of AHAs at 11% including everything from citric to tartaric acid. This one really packs a punch!