Whether it’s because of maskne or the added time spent indoors, it’s safe to say that the pandemic has impacted how we take care of our skin. Some of us are turning to preventative or responsive routines that help decongest the pores or minimise breakouts. And others are looking to brighten and revitalise the skin. Whatever the concern, you’ve probably come across ingredients like AHAs, BHA,s and PHAs.
We spoke to Dr Melvin Tan, Medical Director and Founder of EPION Clinic, and Dr Gladys Teo, Head of R&D of ést.lab to understand the benefits of these chemical exfoliants and how to properly use them.
What are AHAs, BHAs, and PHAs?
AHAs, BHAs, and PHAs are the three main types of chemical exfoliants. AHAs are part of a group of fruit acids. As Dr Tan explains, the most potent one used cosmetically is Glycolic Acid. Glycolic Acid is a strong exfoliant and has the ability to stimulate the skin renewal process. You’ve likely heard of it or seen it in the ingredients list of some of your products. Glycolic Acid helps with smoothening out fine lines, brightening skin, and lightening pigmentation.
Other commonly used AHAs include Lactic Acid which also helps lock in moisture, and Mandelic Acid which has soothing properties and is more useful for sensitive and acneic skin. Dr Teo adds on that for some, AHAs can result in sun sensitivity but you can easily minimise this by using sun protection.
The most notable BHA is Salicylic Acid. It has a similar chemical composition as Aspirin and has excellent anti-inflammatory properties. Which means it is excellent for oily skin, clogged pores, blackheads, and breakout-prone skin. Dr Teo explains that BHAs are more commonly to treat oily skin conditions such as acne. This is because it has the ability to penetrate the pores deeply due to its smaller molecular size and oil-soluble nature.
PHAs or Poly Hydroxy Acids are very mild acids which are related to AHAs. Dr Tan notes that they are in fact second-generation AHAs. PHAs are useful in sensitive skin that’s prone to redness and irritation. Because of their larger molecule size, they penetrate the skin slowly so it’s a more gentle exfoliant. PHAs also help other skincare products penetrate better into the skin.
You might recognise PHA ingredients more commonly as Lactobionic Acid and Maltobionic Acid. Both are strong antioxidants that help protect the skin against UV and free radical damage. It also helps deliver moisture, softness, and smoothness to the skin.
Why should you use chemical exfoliants versus physical exfoliants?
While physical exfoliants like face scrubs can bring an immediate difference, they can sometimes be overly harsh and abrasive. Depending on how you wash your face, it might even lead to dryness and irritation or microtears in the skin.
Chemical exfoliants, on the other hand, are molecular-sized acids or enzymes that penetrate the skin (with varying depths) to loosen up or dissolve dead cells. As Dr Teo explains, this allows them to be easily washed away after. The nature of chemical exfoliants makes it less abrasive and more homogeneous in its exfoliation action compared to physical exfoliants.
These acids also impart additional skin benefits such as reducing fine lines or wrinkles. AHAs can help stimulate collagen. BHAs have anti-inflammatory properties and help with sebum control, and PHAs are power-packed antioxidants that are moisturising on the skin.
Can you combine the different acids?
The short answer is yes. There are several products that combine acids in one go. The combination you choose depends entirely on what your skin needs.
Dr Teo cites how in one case study, a cream containing a blend of AHAs and PHAs has proven efficacy in restoring the condition of dry skin to normal within two weeks. While in another clinical study, 12 weeks of PHA SPF 15 applied during the daytime and AHA lotion applied at night helped significantly reduce hyperpigmentation and improve skin radiance.
AHAs also go well with Ascorbic Acids like Vitamin C as they work well in similar pH conditions. This combination can help combat signs of ageing, while brightening and revitalising the skin.
What are the common mistakes to avoid when using AHAs, BHAs, and PHAs?
The best and safest way to ensure you’re choosing the right hydroxy acid combinations for your skin type is to speak to a trained skincare therapist. Alternatively, Dr Teo explains, you can also refer to product instructions. Or start with acids that have dosages of less than three per cent active acid in total. Be sure to start yourself out by using it two times a week.
Dr Tan and Dr Teo emphasise that you need to follow up with hydrating and moisturising products. This will help bring your skin back to an optimal pH level of 4.7-5.5 and help prevent dryness or irritation.
If you’re new to chemical exfoliants, which acid should you start with?
Depending on what your skin concerns are, the answer will vary. But if you are concerned about the sensitivity of your skin, Dr Teo recommends starting with PHAs. As PHAs are found to be compatible with clinically sensitive skin. You can also consider a product that uses both PHAs and AHAs.
And if you’re new to adding AHAs to your routine, then start with lower dosages of active acids. At around 0.5 to two per cent) at two to three times a week. Even if your product doesn’t indicate the percentage of active acid, you can slowly increase the frequency of usage.
If you want to start adding chemical exfoliants to your routine, here are 13 products to choose from. From cleanser and toners to masks and serums.