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AHA, BHA, And PHA: Which Is The Right Acid For Your Skincare?

We speak to skincare experts to find out what’s the difference between these acids, common mistakes to avoid, and how you can maximise the efficacy of them in your routine.

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 us.

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.

Read: This Star Ingredient Is What Your Skincare Routine Needs Right Now

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.

Read More: 5 Classic Skincare Ingredients Your Skin Will Thank You For

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.

Read More: From Vitamin F To Tranexamic Acid, These Are The Next Big Skincare Ingredients To Know

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.

Read More: 5 Aesthetic Gurus Spill Their Personal Skincare Secrets

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.

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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.

This article first appeared in Women’s Weekly Singapore.

Neutrogena LABS Hydrating Micellar Gel Cleanser, $20.95 for 150 ml
Formulated with the multitasking PHA, this cleanser is gentle on the skin and helps to address multiple skin concerns. The PHAs help to clarify pores, increase evenness of skin tone and clarity, while helping the skin retain moisture. For those with dry skin, the Hydrating cleanser is enriched with hyaluronic acid to help to boost hydration in the skin. Free from soap, sulphates, fragrance, parabens, and 26 of the top allergens, this gentle cleanser is suited for daily use. THEFACESHOP Dr. Belmeur Amino Clear Foaming Cleanser for Acne-Prone Skin, $21 for 150 ml
Using Salicylic Acid, this foaming cleanser is best for acne-prone skin that needs deep cleansing. Formulated with a mild cleansing complex to help minimise irritation, this cleanser also uses ginger extract to increase the antibacterial and purifying benefits. If you’re looking for a cleanser that cleanses the pores thoroughly and keeps it clear of blemishes, then this is one to consider. Kiehl's Daily Refining Milk-Peel Toner, $85 for 200 ml
Gentle enough for daily use, this dual-action exfoliating toner helps to replenish the skin’s moisture levels while lightly exfoliating the skin. Using Lipohydroxy Acid (LHA), a gentler derivative of Salicylic Acid, this toner is gentle to the skin. Especially if you’re new to acids and have sensitive skin. The almond milk also helps nourish the surface for a comfortable feel. Dr Dennis Gross DRx Blemish Solutions Breakout Clearing Gel, $61 for 30 ml
No matter your skincare routine, you’ve likely experienced maskne during this course of time. Powered by Salicylic Acid as well as AHAs like Glycolic Acid, this fast-acting treatment helps to diminish the appearance of breakouts. The two per cent addition of Salicylic Acid gently exfoliates the skin while unclogging pores from within, and the addition of Monk’s pepper helps rebalance visible oiliness around the skin. Yves Saint Laurent Beaute Pure Shots Night Reboot Serum, $139 for 30 ml
This resurfacing serum uses Glycolic Acid to help gently exfoliate and refine the skin overnight. Combined with moisturising oils of Argan and Seed oil and moonlight cactus flowers, this serum helps remove dead skin cells while locking in the moisture of your skin. This medley of power-packed ingredients helps to revitalise the skin and improve skin regeneration over time. Purposeful Skincare By Allies (PSA) Goals Multi Acids & Probiotics Perfecting Night Serum, $58 for 30 ml
With a combination of AHAs and BHAs, this hydrating and multi-acid night serum does all the work for you as you sleep. The ingredients help to reduce breakouts, dark spots, minimise pores so that you wake up with radiant skin. The probiotics also help to strengthen the skin’s barrier, while niacinamide helps increase the skin’s ability to retain moisture. Remember to use SPF the morning after and limit your sun exposure after using this. Pai Skincare Copaiba Deep Cleanse AHA Mask + Cloth, $60 for 75 ml
Powered by AHAs like Lactic Acid and Citric Acid, this deep-cleansing detox mask helps to clear congestion in the skin and refine the pores gently. Enriched with Copaiba, it also helps to soothe the appearance of breakouts and blemishes. This silky clay mask also comes with a muslin cloth to help you remove the mask after eight to 10 minutes. Simply soak it in warm water and wring it out before removing it in gentle circular motions. Guerlain Abeille Royale Double R Renew & Repair Serum, $323 for 50 ml
Using three types of AHAs, this Guerlain Double R serum is for those who want to target a loss of firmness and elasticity in the skin or fine lines and wrinkles. Using antioxidant raw ingredients like black bee Royal Jelly, this serum helps add a deep-hydrating boost of moisture. Glycolic Acid, Lactic Acid, and Citric Acid all help double up on the treatment and help your skin-ageing concerns. Mellow Naturals Clarifying Face Serum with Sophora Root, $59 for 20 ml
Formulated with LHA, a gentle derivative of Salicylic Acid, this 95 per cent natural serum and treatment helps to balance excess oil around the skin, minimise breakouts, and soothe skin irritation. ést.lab Purclear Detoxifying Mask, $98 for 50 ml
Est Lab’s PurClear Detoxifying Mask uses a combination of Mandelic Acid (AHA) and Salicylic Acid (BHA). Mandelic Acid helps to exfoliate dead skin cells and speed up cellular renewal, while Salicylic Acid cleanses the pores of dirt, sebum, and dead cells. Drunk Elephant T.L.C. Framboos Glycolic Night Serum, $190 for 50 ml
Formulated with a unique blend of AHA and BHAs and raspberry extract, this night serum helps to resurface and refine the skin to leave the skin more radiant the next morning. Using ingredients like Horse chestnut, bearberry, and white tea, this serum helps to soothe the skin as it works to reduce the appearance of pores, fine lines, and excess oiliness. As an added bonus, it also helps enhance the efficacy of your products by clearing dead skin cells away for maximum absorption later on. If you experience a slight tingling, know that it’s normal with this product especially within the first few days of application. Start slowly by using it every other night, or use it as a spot treatment. Philosophy Microdelivery Dream Peel, $85 for 50 ml
Loaded with a blend of six per cent AHAs and BHAs, including natural-origin AHAs from hibiscus, the Dream Peel helps to reset and smooth the skin. The probiotic complex and cica agent act as calming and resetting agents and help brighten the skin as you sleep. Caudalie Vinoperfect Glycolic Night Cream, $75 for 50 ml
Our skin works the hardest when we’re asleep, so you might as well add on some power-packed products to your night routine. Formulated with Glycolic Acid, this brightening night cream helps to work overnight and reduce dark spots and even out the skin tone. It also keeps your skin feeling moisturised in the morning and restoring radiance the next morning. The thick and luxurious cream glides on easily, and you can just apply it after your serum. If you want to use it as an overnight mask, simply apply it as a thick layer and rinse it off the next morning.