If you’ve ever stood in front of a skincare shelf wondering whether you should be reaching for glycolic acid, salicylic acid, lactic acid or something else entirely, then you’re not alone. Exfoliating acids can feel confusing at the best of times and, if you don’t already use them regularly, the idea of adding one into your skincare routine can be slightly intimidating. Let’s be honest—hearing the word acid in the context of your face can feel a bit scary. Add in the fact that there’s no one-size-fits-all approach to exfoliation and it all gets a whole lot more complicated.
The good news, however, is that you don’t need to get a degree in chemistry to work out which acid is right for your skin—we’ve created a comprehensive guide to do the hard work for you. You see, different acids work in different ways, with some being suited best for congestion and breakouts, others for dullness, and some for uneven texture and pigmentation. The key is finding one that works with your skin rather than simply opting for the most potent formula you can find. (Trust me, I’ve been there.)
Ahead, we spoke with Dr Ahmed El Muntasar, GP, aesthetics doctor and owner of The Aesthetics Doctor to get the lowdown on exactly how adding an exfoliating acid to your routine can benefit your skin. Plus, we’re breaking down the three main categories (that’s AHAs, BHAs and PHAs) and sharing the key acids within each, as well as product recommendations, so you can work out which ones will work for you.
What Are Exfoliating Acids?
Simply put, exfoliating acids are chemical compounds that help to dissolve the bonds between dead skin cells and the skin in order to remove them more effectively. “Rather than relying on physical scrubs, exfoliating acids help the cells to shed more evenly and the result is smoother, brighter-looking skin, improved texture and, over time, a more even skin tone,” explains Dr El Muntasar. And it’s not just surface changes either. “Depending on the acid, they can also help unclog pores, reduce breakouts, soften fine lines and improve the absorption of other skincare products,” says Dr El Muntasar.
If you’re a little hesitant to get started, then good news: Dr El Muntasar points out that exfoliating acids are actually one of the most well-researched and effective categories of skincare ingredients, as long as they’re used correctly. “The biggest mistake that people make with exfoliating acids is doing too much too quickly,” says Dr El Muntasar. “People often combine multiple exfoliating acids with retinoids, vitamin C and physical scrubs, thinking they’ll get faster results. In reality, that usually leads to irritation, dryness and a compromised skin barrier.” He also suggests starting out slowly—just once or twice a week and increasing if your skin is tolerating the ingredient well. Plus, SPF is key. “Freshly exfoliated skin is more vulnerable to UV damage, so sunscreen becomes non-negotiable and daily SPF even more important,” Dr El Muntasar explains.
Who Should Use Exfoliating Acids?
As we’re talking about such a large category of products, most people actually will be able to find an exfoliating acid that works for them. However, Dr El Muntasar points out that they might not be suitable all of the time. “If your skin barrier is damaged, you’re experiencing an eczema flare, active dermatitis or significant irritation, I would usually focus on repairing the barrier before introducing exfoliation,” he explains.
As for those with sensitive skin? He advises that you don’t need to avoid acids altogether if you have rosacea or sensitivity, but should choose gentler acids (like lactic acid or PHA), introduce them gradually and use them less frequently. “Stronger isn’t always better anyway,” explains Dr El Muntasar. “A lower-strength product used consistently often gives better long-term results than an aggressive product that leaves the skin inflamed.”
Every exfoliating acid has its own strengths and Dr El Muntasar advises that “the best acid really depends on the skin concern you’re trying to treat rather than assuming one is universally better than another”. So, with that in mind, keep scrolling as we get into the three main types of exfoliating acids—AHAs, BHAs and PHAs—and explain what they do, who they’re best for, and the best products to shop from each.
Alpha Hydroxy Acids
Alpha Hydroxy Acids, or AHAs, are water-soluble acids that work primarily on the surface of the skin, loosening the bonds between dead skin cells and encouraging them to shed to leave your skin smoother, brighter and more even. They’re particularly useful if your main concerns are dullness, rough texture or uneven skin tone.
“Glycolic acid is excellent for improving dullness, pigmentation and fine lines because its small molecular size allows it to penetrate effectively, while something like lactic acid is slightly gentler and also attracts water into the skin, making it a great choice for people with dry or more sensitive skin,” says Dr El Muntasar.
Glycolic Acid
The smallest AHA molecule, glycolic acid, can penetrate effectively into the skin, making it one of the more powerful exfoliating acids. It’s particularly good for improving dullness, uneven texture and the appearance of pigmentation and fine lines.
This cult exfoliating treatment makes light work of lifting away dead skin cells to remove smooth, glowy skin beneath.
This viral glycolic acid stick is more than just a TikTok craze, it genuinely works to refine the texture of your skin on areas like the knees or backs of the arms.
A budget-friendly toner containing 5% glycolic acid to exfoliate and brighten.
Lactic Acid
A slightly gentler AHA than glycolic acid, lactic acid exfoliates while also helping to support skin’s moisture levels. It’s a good option for dry or dehydrated skin that still wants the benefits of chemical exfoliation.
This is a great beginner option if you’re new to lactic acid (The Ordinary also offers a 10% version) as the serum is supported with hyaluronic acid to to support skin hydration while improving the appearance of pigmentation and uneven texture.
A refreshing daily toner that gently exfoliates, cleanses pores, and boosts radiance without compromising that all-important skin barrier.
This clever liquid treatment can be left on skin for a few minutes to shift dead skin cells, reduce the appearance of dark spots and pigmentation and even skin tone. It’s pricey, but with 10% lactic acid you’ll notice brighter skin from first use.
Mandelic acid
With a larger molecular size than glycolic and lactic acids, mandelic acid tends to exfoliate more slowly and gently. It can be a good choice for sensitive or blemish-prone skin and can help with uneven tone and texture.
Korean skincare brands always deliver when it comes to essences and toners, and this mandelic acid formula is a gentle multitasker that nourishes skin while improving clarity.
Combining mandelic and lactic acids together, this popular exfoliant is brilliant if you’re looking to combat dullness or pigmentation without relying on harsh treatments. Skin will be left baby soft and smooth.
If you’re concerned about bumpy skin, dry patches or fine lines, but are prone to sensitivity, this gentle serum aims to resurface the skin without causing irritation.
Malic acid
Found naturally in fruits such as apples, malic acid is a larger AHA that offers relatively gentle exfoliation. It’s often combined with other acids rather than used alone, helping to brighten and smooth the skin.
There are very few hero malic acid products on the market, but Votary’s Daily Apple Toner is one of them. It also contains lactic acid and probiotics to gently brighten and smooth skin while keeping the skin’s microbiome balanced and healthy.
Having just landed in the UK, Prequel is already being raved about by Who What Wear editors for how glowy the products leave skin—and this multi-acid peel does exactly that. There’s a whole host of AHAs here, including malic, to unclog pores, refine texture and restore radiance.
If you love that freshly cleansed feeling, then this exfoliating gel can be massaged onto damp skin before rinsing clean away to leave your face so soft and bright.
Beta Hydroxy Acids
The first thing to know about beta hydroxy acids, or BHAs, is that they are oil-soluble. “That means they can travel into pores to dissolve excess oil and debris, making them the gold standard for oily, acne-prone or congestion-prone skin,” says Dr El Muntasar. “The primarily used BHA is salicylic acid, which is particularly useful for blackheads and recurrent breakouts.” BHAs also help to dissolve the build-up of oil and dead skin cells that can contribute to congestion, while also providing surface exfoliation.
Salicylic acid
The best-known BHA, salicylic acid, is oil-soluble and can penetrate into pores to help clear excess sebum and dead skin cells. It’s particularly useful for breakouts, blackheads, congestion and oily skin.
This is a bit of a multipurpose hero for spot-prone skin, as the combination of salicylic and glycolic acids here help to buff away dead skin cells, decongest pores, and brighten the skin. Plus, it also contains niacinamide which helps to soothe.
One of the most popular exfoliating acids ever, Paula’s Choice cult salicylic acid toner targets congestion, blocked pores and breakouts with such efficacy that you’ll notice clearer, calmer skin in just a couple of weeks.
For skin that tends to get really oily and shiny by midday, this clarifying toner will help to dial back that sheen and keep skin balanced, calm and mattified for longer.
Polyhydroxy Acids
Polyhydroxy acids (PHAs) are often considered the gentler cousins of AHAs. “They have larger molecules, so they penetrate more slowly and tend to cause less irritation,” explains Dr El Muntasar. “They’re ideal for people with sensitive skin, rosacea-prone skin or those new to exfoliating acids. They still improve skin texture but are generally much better tolerated.” They also have humectant properties, meaning they can help attract and retain moisture in the skin. They won’t necessarily deliver the same intensity of exfoliation as an AHA or BHA, but they can be a useful option for maintaining smoother, brighter-looking skin without overdoing it.
Gluconolactone, lactobionic acid and galactose
PHAs are one of the less-readily available exfoliating acids in the UK market, so we’re going to lump the key acids together in one here. Gluconolactone is the most common, and works to gently exfoliate the skin while helping to attract moisture—a great option for sensitive or dehydrated skin. Derived from lactose, lactobionic acid is another gentle PHA with exfoliating and humectant properties. It can help improve the appearance of texture while supporting skin hydration. Finally, galactose is a naturally occurring sugar that can be used in PHA formulations.
The star PHA here is gluconolactone, to help unify skin tone gently while a host of hydrating ingredients like aloe vera, acai and prickly pear work to brighten and smooth.
If you’ve no time for a facial before a big event, then this efficacious treatment harnesses 15% PHAs and 10% AHAs to really buff away dead skin cells, decongest pores and leave skin noticeably smoother, more even and brighter. Despite how potent it is, though, it doesn’t sting and actually leaves skin feeling hydrated afterwards.
Again, it’s glunolactone which is the PHA at play here, supported by niacinamide to improve skin texture and balance excess oil—a particularly good choice for combination skin types.
Why Trust Us
At Who What Wear UK, we know that beauty isn’t one-size-fits-all. Our editors have tested thousands of products over the years—spanning skincare, makeup, hair and nails—and work closely with trusted experts including dermatologists, makeup artists and leading industry insiders to ensure every guide is well-researched, inclusive and relevant to you.
We focus on formulas that deliver, whether they’re affordable favourites or luxury investments. Our product selection is based on tangible results, ingredient know-how and what we’d truly recommend to a friend.
