the skin edit.

Exfoliating acids in skincare explained

Skincare enthusiasts swear by exfoliating acids because they’re effectively a fasttrack to healthy, glowing skin and a smooth complexion. Acids work on the skin in two ways, depending on the type: they break down the bonds between dead skin cells to slough them away and reveal a brighter, fresher complexion, or they penetrate deep into the pores to clear build-up and prevent breakouts.

You can incorporate an acid into your routine in different ways – via toners or peels or serums for example. A toner is a solution that you sweep onto your face with a cotton pad after cleansing, a serum is applied to the skin before moisturising, while a peel is used as a mask that you rinse or lift off.

Whichever delivery method you choose, it’s important to understand the benefits of incorporating an acid into your routine:

Acids accelerate cell-turnover
Essentially, they act like a trip to the gym for your skin. An acid toner will stimulate the production of elastin and collagen, contributing to a robust and firm complexion.

Acids restore radiance
Sometimes, something is just not quite right. You’ve cleansed, serumed, and moisturised, but there’s just something dull about the face that’s looking back at you in the mirror. Dull skin is a subtle yet damning skin complaint that arises when dead cells build up on the surface of the dermis. An acid toner will slough away dead cells, restoring your skin to glorious radiance.

Acids prepare your skin for other products
A hidden benefit that is not to be underestimated – because acids exfoliate the surface of the skin, decongesting pores and sloughing away dead skin cells, they hugely increase the penetration of subsequent products. Serums, spritzes, night oils and masks become more effective because they are able to work better.

There are two main groups of acids used in skincare: AHAs and BHAs.
AHAs, or alpha hydroxy acids are water soluble, which means that they can’t penetrate the skin’s natural oils. So these acids work on the surface layer of the skin. Common AHAs include glycolic acid, mandelic acid, and lactic acid.

Glycolic acid and lactic acid are probably the two most widely-used AHAs. While they are both excellent for helping to even-out skin tone, lift pigmentation, and fade scarring, lactic acid also acts as a humectant, attracting hydration to the skin.

Really, the only BHA, or beta hydroxy acid in skincare is salicylic acid. BHAs are oil soluble so they can penetrate deep into the pores and help to remove excess sebum. Salicylic acid based toners are great for clearing the complexion and preventing breakouts but can be quite harsh for skin.

We’ve decoded the most common acids in skincare in this post so you can figure out which acid is best for you.

Overusing acids – either by using too many products containing acids in your routine, or using one product that’s too concentrated – can damage the outer skin layer, which leads to itchy, red, inflamed, flaky skin.

That’s why it’s important to start slowly and with a product that is at a concentration that’s strong enough to work, but not so strong that it will cause sensitisation.

• Don’t overuse an AHA product at the start. Too much too soon can cause problems so start with your AHA product every other day and build up to daily as your skin adjusts

• Don’t mix AHA products – this causes overstimulation and unhappy skin!

• Use an acid product that also contains supporting natural ingredients to calm and nourish skin

• Spritzing after using an acid toner is a great way to soothe and calm the skin

The idea that there’s acid in your skin-care products may sound scary. But in reality, they’re game-changers in the quest to achieve smooth, even-toned, radiant skin.

If you’re anxious about including an acid toner in your routine, you’re not alone. Many people suffer from dry or sensitive skin and worry that an acid will make matters worse.

Your friend in this case is AHA lactic acid. Lactic Acid is a sensitive skin hero, gentle enough for use on all skin types. It improves the skin’s natural moisture factor, or the means by which the skin keeps itself hydrated. Use a lactic acid toner, such as Pestle & Mortar’s lactic acid toner, NMF, if your skin feels dry and unbalanced, or if you worry about irritation.

Shop mentioned products


Lactic Acid Toner - 200ml



Glycolic Acid Toner - 180ml


The Pestle and Mortar Exfoliate is a gentle glycolic acid solution blended with natural extracts and niacinamide to remove dead skin cells and reveal brighter-looking skin.


Glycolic Acid Toner - 80ml


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