Liquid exfoliators: How to use facial acids to smoothen normal skin, oily skin and even dry skin
Facial acids — besides the hyaluronic one — have long had a maligned rep of burning off your face the way the sun sizzles vampires to death. But just like the latter, it's all myth. In fact, these misunderstood chemicals are what the derms use in peels to achieve that baby's bottom complexion for their clients (and like most products in the beauty industry) have slowly trickled from cosmeceutical to consumer.
Known as liquid exfoliators or exfoliating toners to the laywoman, the current boom in acid-based skincare has seen cool brands the likes of Drunk Elephant, Sunday Riley, and Allies of Skin turning out a crop of new-gen products formulated with various acids (lactic, salicylic, et cetera) that promise smoother, glowing skin and fewer fine lines. More than just a trend though, it's a skincare change in the way we scrub: no more rubbing yourself raw with harsh, physical exfoliants.
Naturally, sorting out your AHAs from your BHAs can be daunting for those easing themselves into this pool, which is why we've put together this primer to catch you up quick on everything from the benefits of using acids to application no-nos. Chemistry degree not required. Time to retire those gritty face scrubs from your bathroom shelves.
Knowing the difference between AHAs and BHAs
AHA and BHA are acronyms for alpha-hydroxy acid and beta-hydroxy acid. The former is water soluble and fab at sloughing off dead skin to reveal brighter, healthier skin while the latter is oil soluble and is particularly effective for blemish-prone complexions.
Sometimes also labelled as fruit acids, the most common AHAs used in liquid exfoliators are lactic, citric and glycolic acid. They help boost skin cell turnover rate and they're generally preferred for normal to dry skin. On the other hand, BHAs such as salicylic acid are great for pore cleansing, reducing inflammation, and preventing spots — making them a mainstay ingredient in anti-breakout solutions. It's even gentle enough for those with sensitive skin types or rosacea.
Knowing your acids
Salicylic acid: Has anti-bacterial and anti-inflammatory properties, usually derived from aspirin. Those with an allergy to said drug will have to stay away from this one.
Glycolic acid: It's the AHA with the smallest molecule and has been in use for a quite while now. Derms know this one as the oldie-but-a-goodie, all-rounder exfoliant.
Lactic acid: With a larger molecule size compared to glycolic acid, this takes a little longer to penetrate, which gives the skin that crucial moment to adjust to the pH drop. It also has hydrating properties, making it the go-to of skin doctors.
Kojic acid: A by-product in the fermentation process of sake, it's primarily used for lightening the skin and targeting pigmentation.
Mandelic acid: Derived from bitter almonds, this one's known treating fine lines, acne, and pigmentation.
Knowing the benefits
Way more multi-faceted than ordinary face scrubs, liquid exfoliators are packed with complexion-boosting benefits such as accelerating skin cell turnover, smoothing out uneven pigmentation or texture, and clearing congested pores. Fine lines and wrinkles are also diminished over time, and the skin looks and feels firmer. The acids even act as a booster to allow your following serums and moisturisers to be better absorbed.
But do take note that not all liquid exfoliators are made equal. Those with sensitive skin are more suited to enzyme-based exfoliators and should look out for formulas with lactic acid and BHAs. And if you've a darker skin tone, you need to ensure the product isn't causing an inflammation response, as this can result in a pigmentation reaction down the road that'll lead to a patchy skin tone.
Knowing the how-to-use
Start with small and work your way up. Going in strong (or kiasu) with anything above a 10% acid concentration is what causes the redness and burning as your skin won't be able to take the sudden chemical onslaught. Just in case, a patch test on the neck is recommended before you tackle your face. Go with a once-weekly application in the beginning to give your skin time to adjust to the pH change.
Once it has adapted, you can switch to a product with a higher acid percentage and exfoliate up to two or three times a week, depending on the strength of the formula. There's also room for experimentation if you're interested in combining AHA and BHA formulas once you're familiar enough with the liquid exfoliator game. You'll have to keep fine tuning to see what works best for your skin though as the different acids provide separate benefits. Alternatively, some products already come with both acid types, such as Glossier's Solution. And remember: never ever skip the SPF, especially post-exfoliation, as AHAs and BHAs increase the skin's sensitivity to sun exposure.
Check out the liquid exfoliants to get you started: