A popular step in the Korean skincare routine is using products containing the chemical exfoliants: AHA and/or BHA. Both these ingredients have fantastic benefits for our skin, but which one is better in helping to clear acne?
In short, both AHA and BHA are effective at combating acne although they both do so in slightly different ways. Which chemical exfoliant works best for your skin also depends on your skin type, with AHA being better suited for dry skin and BHA being better suited for oily skin. However, you can still benefit from both AHA and BHA (no matter what your skin type) by following a few simple skincare tips that I discuss in this post.
Understanding Chemical Exfoliants
Before we get into the nitty gritty of whether AHAs or BHAs are better for treating acne, I first need to give a little bit of information about what these ingredients actually are, and how they work on your skin.
AHAs (alpha hydroxy acids) and BHAs (beta hydroxy acids) are both forms of chemical exfoliants. We all know that we need to exfoliate our skin from time to time to remove dead skin cells and unclog pores, but Western skincare often calls on physical exfoliants (I’m looking at you – apricot scrub) – which can be too harsh and abrasive for the skin – especially if you have acne!
Chemical exfoliants are much gentler on the skin and are non-abrasive (although too much of a good thing can be bad for your skin too). They are suitable for acne-prone skin and as you’ll see, both actually work well at minimizing both acne and acne scaring.
AHA and BHA exfoliants are typically leave-on, and they really make a big difference in the appearance of your skin. Besides having acne-fighting properties, AHAs and BHAs also minimize the appearance of wrinkles, unclog pores, smooth rough and bumpy skin, even out skin tone and increase skin hydration.
How AHA and BHA Are Similar
As I’ve already mentioned, both AHA and BHA are chemical exfoliants used to help the skin gently exfoliate its build up of dead skin. Both AHAs and BHAs are naturally found in many plants.
AHA and BHA are similar in that they both act to unglue the bonds between the dead skin cells on the outer layer of the skin, allowing the skin to naturally ‘shed’ it’s dead cells – revealing new and healthier cells to come to the surface.
Our skin actually naturally exfoliates dead skin cells (also called skin turnover), however over time as we age, this process slows down. Both AHA and BHA speed up the cell turnover rate, improving the appearance of our skin.
This ability of AHA and BHA to remove old skin faster, is what makes them great ingredients for fading hyperpigmentation too (check out my post on how to fade hyperpigmentation here).
How AHA and BHA Are Different
Chemically, AHA and BHA are very similar, although they differ in size – with salicylic acid (BHA) being a much larger molecule than most AHAs. The main point of difference between AHA and BHA is that AHA is water soluble and BHA is lipid (oil) soluble.
This means that AHA can only work on the skin’s surface, while BHA can penetrate deep inside the pore – effectively unclogging the gunk consisting of dead skin cells, sebum and bacteria (that can lead to acne).
Types of AHA
The most common AHA used in skincare is glycolic acid, which is mostly derived from sugar cane (although it can be derived from other plants high in sugar).
Other forms of AHA used in skincare products are:
lactic acid (derived from milk), citric acid (derived from citrus fruits), malic acid (derived from apples and pears), tartaric acid (derived from grapes), and mandelic acid (derived from bitter almonds).
Types of BHA
There is only one form of BHA: salicylic acid – which is actually a naturally occurring hormone produced by plants as an environmental or pathogenic stress defence mechanism. It is mostly synthesized from willow bark.
Although citric acid is primarily classified as an AHA, it can sometimes also considered a BHA depending on its formulation.
Does AHA Help With Acne?
Although conventional skincare advice is that BHA works better for acne, AHA can actually help to improve acne too – since it also helps to exfoliate dead skin cells from the surface of the skin (therefore preventing pores from becoming clogged).
Although AHA can’t penetrate deep inside the pores, its small molecular size and water-loving properties make it really good at getting in between the layers and layers of dead skin cells on the surface of our skin.
Because AHAs exfoliate dead skin cells at the surface of the skin, they are more beneficial if you have inflammatory acne – since inflamed comedomes are located at the surface of the skin.
Glycolic acid in particular, is the most effective (and most researched) form of AHA as it has the smallest molecular size. There is a lot of research which shows the effectiveness of glycolic acid in the treatment of inflammatory acne (see a very detailed scientific review here).
My favorite Korean skincare product with glycolic acid is the COSRX AHA 7 Whitehead Power Liquid (available at Yesstyle, Jolse and Amazon). This exfoliant also contains apple water (which contains natural AHA), niacinamide (see my article on the benefits of niacinamide here), panthenol and sodium hyaluronate.
Other AHAs, such as mandelic acid have a much larger molecular size and therefore aren’t as effective at getting in between the layers of dead skin like glycolic acid can. However, they are much gentler on the skin and may therefore be a good option for people with sensitive skin or rosacea.
This study here showed that products containing 5-10% mandelic acid are both safe and effective at treating acne.
If you’re after a Korean skincare product containing mandelic acid, then I recommend the Mandelic Acid 5% Skin Prep Water from the Korean skincare brand By Wishtrend (you can buy it here from Yesstyle.com). This toner works really well at healing inflamed blemishes due to the 5% mandelic acid it contains (as well as beta-glucan, panthenol, Centella asiatica and sodium hyaluronate).
Additional Benefits of AHA
Besides helping to improve acne, AHAs have a wide range of other skin benefits. The exfoliating properties of AHA also mean that this is a great ingredient for improving acne scars and fading hyperpigmentation (as exfoliation removes pigmented skin and reveals a healthier layer of skin underneath).
I have written quite a lot about how to fade hyperpigmentation on this website already (for example, here and here), but in case you don’t have time to read everything right now I will mention that fading hyperpigmentation requires lots of patience and persistence as it does take some time to slowly peel away dark marks.
AHAs also have the added benefit of improving the moisture content of the skin (since they are water-loving molecules).
This means that they are generally preferred for people with normal to dry or sun-damaged skin (although oily skin types can still benefit from using products containing AHA as well).
AHA is also a great anti-aging ingredient as it is effective at decreasing fine lines and wrinkles due to it’s ability to stimulate collagen production and exfoliate and resurface the skin.
Does BHA Help With Acne?
While AHA works to decrease acne on the surface of the skin (such as inflammatory acne), BHA works really well at clearing blackheads and preventing acne that is caused by clogged pores.
Remember, I mentioned that BHA is oil-soluble? Well, acne is often caused by oil (sebum), dead skin cells and other gunk (such as dirt, makeup and other skincare products) getting clogged in our pores – leading to the perfect breeding ground for acne-causing bacteria.
AHA molecules are water-soluble and so can’t penetrate into the pores to clear this oily acne-causing mess, whereas BHA can.
Salicylic acid is considered to be the only true form of BHA, and there is a lot of research that shows it effectiveness at treating acne.
This scientific review of four clinical studies showed that salicylic acid pads (with salicylic acid concentrations of 0.5 to 2%) were effective at reducing the number and severity of acne lesions.
This study showed that salicylic acid (2% solution) was just as effective as a 5% benzoyl peroxide solution in the treatment of mild to moderate acne (including papules/pustules and non-inflammatory lesions).
This very recent study (only published in April 2019) showed the molecular pathway by which salicylic acid unclogs pores and reduces lipid production. The researches also found that in addition to decreasing oil production in pores, that salicylic acid also has strong anti-inflammatory properties.
But, Do Korean Skincare Products Contain Salicylic Acid?
So, studies have shown that salicylic acid in concentrations as low as 2% are effective in treating mild to moderate acne. Salicylic acid seems to be a common ingredient in Western skincare products, but did you know that its use is actually restricted in Korea?
This means that Korean BHA skincare products either only contain very low concentrations of salicylic acid (below 0.5%) or use other ingredients in its place, such as betaine salicylate and willow bark extract.
Of course, these two ingredients aren’t BHAs, chemically speaking, so it’s confusing (and perhaps a little misleading) to have products labelled as containing BHA or salicylic acid.
What Is Betaine Salicylate?
Betaine salicylate is a derivative of salicylic acid (it’s molecular structure is the same as salicylic acid with a betaine group attached). It’s derived from sugar beets and is commonly used as an alternative to salicylic acid in Korean skincare products.
The benefits of betaine salicylate are promising and it appears to be a very effective exfoliant and acne-preventing ingredient. It’s also less irritating and less drying than salicylic acid, due to the betaine group it contains.
However, I couldn’t find any independent scientific studies comparing the effectiveness of betaine salicylate against salicylic acid.
The only research on betaine salicylate is by the company Arch Personal Care Products, the manufacturer of this ingredient – who found that betaine salicylate shows comparable effects to salicylic acid at double the concentration (you can read the study here if you like).
This means that skincare products need a concentration of 4% betaine salicylate to be as effective as skincare products containing 2% salicylic acid.
The Korean BHA that I’m currently using and have seen extremely good results with is the COSRX BHA Blackhead Power Liquid (available at Yesstyle, Jolse and Amazon). It’s the most popular Korean BHA skincare product and it contains 4% betaine salicylate as well as willow bark extract (which I’ll talk about next).
Here is a full ingredients list for the COSRX BHA Blackhead Power Liquid (with beneficial ingredients in bold):
Salix Alba (Willow) Bark Water, Butylene Glycol, Betaine, Niacinamide, Betaine Salicylate, 1,2-Hexanediol, Sodium Hydroxide, Sodium Hyaluronate, Panthenol, Xanthan Gum, Ethyl Hexanediol
I love how minimal COSRX ingredient lists are! But, I digress. Let’s keep going.
What Is Willow Bark Extract?
You may have noticed Korean skincare products containing willow bark extract or willow bark water before. But what is this ingredient?
As I’ve already mentioned above, salicylic acid is most commonly derived from willow bark. This is because willow bark contains the chemical salicin, which in the presence of certain enzymes, converts into salicylic acid.
However, our skin doesn’t contain these enzymes. This means that the salicin in willow bark extract or willow bark water simply cannot be converted to salicylic acid on our skin.
So why do so many Korean skincare products (including my beloved COSRX BHA Blackhead Power Liquid) contain willow bark? The answer is partly marketing (since we associate willow bark with BHA), but also that willow bark has soothing and anti-inflammatory effects on the skin – making it a great ingredient for fighting acne.
Can BHA Cause Breakouts?
Since this article is about how BHA is an effective ingredient for fighting acne, I’d like to address a commonly asked question – can BHA cause you to breakout?
The answer is yes, when used too often or in high concentrations, BHA can cause skin irritation and drying – leading to more acne. If you’re wanting to have clearer skin, it’s so important to look after your skin’s moisture barrier (to prevent production of excess sebum) and to reduce inflammation to your skin.
Personally, I only use my COSRX BHA Blackhead Power Liquid twice a week (as part of my evening routine). I found that using it more than this did irritate my skin a little, leading to more pimples.
Of course, how often you use BHA in your skincare routine depends on your skin and what type of product you are using. Always follow the product directions. If you haven’t used products containing BHA before, I would recommend to introduce the product slowly (perhaps applying it only weekly in the beginning) and increase the frequency with which you use the product from there (if your skin is tolerating it well).
Additional Benefits of BHA
I’ve already briefly mentioned some of the additional benefits that BHA has for the skin, including that it has anti-inflammatory properties – helping to soothe the skin and reduce irritation.
Even if you don’t have acne, BHA helps to regulate the production of sebum within the pores of your skin – which is why it is so highly recommended for oily skin types. Just make sure you don’t overdo it, as this can dry out your skin, leading to an increase in oil production as well as skin irritation.
Similar to AHAs, BHA is also a great ingredient to include in your skincare routine if you’re wanting to fade hyperpigmentation. Studies have shown the effectiveness of salicylic acid against post-inflammatory hyperpigmentation and melasma for various ethnic groups (see studies here, here, here and here).
Some of the studies I linked to above also found that BHA has anti-aging benefits, with results showing improvements in photo-aging and fine lines and wrinkles. The mechanism by which BHA is able to improve signs of aging are not yet properly understood and more studies are needed in this area.
Can You Use AHA And BHA At The Same Time?
You don’t have to use both an AHA and a BHA to get the best results (you will get remarkable results using either on their own). As I’ve found while researching for this article, both AHA and BHA work great at exfoliating the skin and preventing acne – they just work in slightly different ways.
However, it is possible to include both an AHA and BHA in your skincare routine if your skin requires more thorough exfoliation (to address more advanced signs of aging, hyperpigmentation and stubborn clogged pores) by alternating their use.
How you alternate your AHA and BHA products really depends on how well your skin tolerates chemical exfoliation and on the strength of the products.
For example, your skin might only tolerate using a chemical exfoliant once or twice a week. If your skin tolerates chemical exfoliation well (you can work up to this), you could alternate using either an AHA or BHA every evening.
It may take some time to work out what frequency and combination of exfoliation works best for your skin. The important thing to remember is to start small and work your way up from there if your skin is tolerating the products you’re using well.
AHAs and BHAs are chemical exfoliants that have become hugely popular in Korean skincare and are much preferred over physical exfoliants (as these can be damaging to the skin).
There are a handful of different forms of AHA available, however only one form of BHA exists (salicylic acid). The use of salicylic acid in skincare products is very restricted in Korea, and therefore Korean skincare products often use betaine salicylate (a derivative of salicylic acid) or willow bark extract/water in its place.
AHA and BHA work in slightly different ways – with AHA breaking apart dead skin cells on the surface of the skin and BHA being able to penetrate deep into the pores to unclog them.
As it turns out, both AHA and BHA have properties that make them beneficial for acne-prone skin. Neither is better than the other when it comes to helping acne, although AHA may be better at treating inflammatory acne located at the surface of the skin, while BHA is better at preventing pores from becoming clogged and forming blackheads and non-inflammatory acne.
I hope this article has given you some useful information about AHA and BHA and how both can be used to treat and prevent acne. Let me know in the comments if there is an AHA or BHA product that has worked well for your skin (especially if you have acne-prone skin).
If you need more information about how to get rid of acne, then check out the following articles I’ve written:
- Korean & Japanese Water-Based Cleansers For Oily And Acne-Prone Skin (a guide to choosing the best water-based and low pH cleanser with product recommendations)
- The Best Korean Skincare Products For Oily And Acne-Prone Skin (a guide to the most effective ingredients for acne with product recommendations).