Chemical exfoliation has quietly become one of the most transformative steps in a modern skincare routine. Where once we relied on gritty, harsh scrubs that left skin raw and irritated, a few well-chosen acids now dissolve the bonds holding dead skin cells together — revealing the smoother, brighter, clearer complexion underneath. But with three heavyweight names dominating the conversation — glycolic acid, lactic acid, and salicylic acid — the question is no longer whether to exfoliate, but which acid is right for your skin.
Choose well and the results can be remarkable: faded pigmentation, refined pores, fewer breakouts, and a visible lift in radiance. Choose poorly and you will end up with tightness, stinging, and a compromised skin barrier. So let’s break down what each acid actually does, how it behaves on different skin types, and how to slot it sensibly into your routine.
The Two Families: AHAs and BHA
Before comparing the three, it helps to understand the families they belong to.
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Alpha Hydroxy Acids (AHAs) are water-soluble acids that work on the skin’s surface. They dissolve the "glue" (desmosomes) between dead skin cells, encouraging them to shed evenly rather than piling up and dulling the complexion. Glycolic and lactic acids both belong to this family.
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Beta Hydroxy Acid (BHA), of which salicylic acid is the best-known example, is oil-soluble. That single chemical difference is what makes it so distinctive: instead of working only on the surface, salicylic acid can travel down into the pore lining, where it dissolves the mix of sebum and dead cells that causes blockages, blackheads, and spots.
In short: AHAs are resurfacers; BHA is a decongestant.
Glycolic Acid: The Radiance Powerhouse
Glycolic acid is the smallest AHA molecule — derived from sugar cane — which means it penetrates the skin quickly and deeply. That penetration is what gives glycolic its reputation for visible, fast results: smoother texture, a more even tone, softened fine lines, and a noticeable glow.
It is particularly effective for normal to dry, sun-damaged, or mature skin showing signs of dullness, uneven pigmentation, and rough texture. By accelerating cell turnover, glycolic acid helps fade surface pigmentation and gives skin a fresher, more luminous appearance.
The flip side of that small molecule size is potential irritation. Glycolic acid can sting sensitive skin, and at higher concentrations, it can disrupt the barrier if overused. Starting at a moderate concentration and building up gradually is the sensible approach — and pairing it with a good moisturiser and daily SPF is non-negotiable, because freshly exfoliated skin is far more vulnerable to UV damage.
This is where a thoughtfully formulated cleanser comes into its own. The REFORM Skincare Glycolic Acid Foaming Cleanser contains 10% glycolic acid — a concentration that delivers genuine exfoliation while remaining manageable for daily use in a wash-off format. Because it is washed off rather than left on the skin, it is an accessible way to introduce glycolic acid without committing to a leave-on treatment, and the foaming base helps lift makeup, dirt, and dead skin in a single step. For anyone whose main concern is dullness or uneven texture rather than active breakouts, it provides a strong daily foundation.
Lactic Acid: The Gentler Hydrator
Lactic acid, derived from milk (though synthetically produced in modern formulations), is a larger AHA molecule than glycolic. That larger size means it penetrates the skin more slowly, making it inherently gentler and better tolerated by sensitive, reactive, or drier skin types.
But lactic acid has a second trick up its sleeve: it is a humectant. As well as exfoliating, it draws moisture into the skin, supporting the hydration that sensitive and mature complexions so often lack. The result is a softer, plumper, more even-toned appearance — without the tightness that stronger acids can leave behind.
Lactic acid suits dry, sensitive, mature, or rosacea-prone skin particularly well. If glycolic acid has felt too aggressive, or if your skin reacts easily to active ingredients, lactic acid is often the smarter first step. It is also a sensible choice during the colder British months, when our skin barrier is already stressed by central heating and harsh weather.
While REFORM Skincare’s exfoliating range leans on glycolic and salicylic acids, the brand’s Gentle Hydrating Crème Cleanser is worth highlighting here as the ideal partner product for anyone whose skin is too sensitive for daily acid use. A non-foaming, non-stripping cleanser preserves the moisture lactic acid users are working so hard to maintain — allowing you to reserve acid exfoliation for a dedicated treatment step a couple of times a week instead.
Salicylic Acid: The Pore Decongestant
Salicylic acid is structurally different. As a BHA, its oil solubility allows it to penetrate deep into the pore itself, where it dissolves the keratin plugs and oxidised sebum that lead to blackheads, whiteheads, and spots. It also boasts mild anti-inflammatory properties, which is why it is so well tolerated by acne-prone skin that is already red and reactive.
This makes salicylic acid the standout choice for oily, combination, and blemish-prone skin. If your main concerns are congestion around the nose and chin, persistent breakouts, enlarged-looking pores, or excess shine throughout the day, salicylic acid addresses the root cause rather than just the surface symptom.
The REFORM Skincare Salicylic Acid Foaming Cleanser is purpose-built for this profile. Formulated as a deep cleanse for oily skin, its lightweight formula removes excess oil and makeup while working within the pore lining to reduce blackheads and prevent breakouts — all without leaving skin feeling stripped or dry. Used daily, it sets up a clarifying, spot-fighting routine perfectly.
For more stubborn or widespread congestion, REFORM Skincare also offers the Anti-Blemish Kit, a three-step system pairing the Salicylic Acid Foaming Cleanser with an Anti-Blemish Crème and the brand’s Repair & Renew Gel. The gel is a particularly clever addition: an at-home resurfacing treatment combining mandelic acid (a large, gentle AHA), glycolic acid, and phytic acid to brighten and decongest. It can be used on both the face and body, making it notably effective for back breakouts ("backne") and keratosis pilaris (often called "chicken skin"). The combination of BHA in the cleanser with AHAs in the treatment gel covers both surface and in-pore concerns, which is exactly the kind of layered approach congested skin benefits from.
Matching the Acid to Your Skin Type
The right acid is the one that meets your skin where it is, not the one with the highest concentration.
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Normal, dull, or sun-damaged skin: Glycolic acid. For accelerated resurfacing and radiance, a daily glycolic cleanser is the workhorse choice.
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Dry or dehydrated skin: Lactic acid, for its dual exfoliating and hydrating action. Pair with a cream-based cleanser to avoid stripping moisture.
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Sensitive or reactive skin: Lactic acid at low concentrations, or mandelic acid (as in the Repair & Renew Gel), introduced gradually and never layered with other actives on the same night.
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Oily, combination, and spot-prone skin: Salicylic acid. The BHA’s deep pore penetration is what makes all the difference here.
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Body breakouts or keratosis pilaris: A multi-acid gel like Repair & Renew, applied a few times a week to affected areas.
A Few Rules for Getting It Right
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Less is more. Exfoliating every single day with a leave-on acid is rarely necessary and often counterproductive. A daily acid cleanser plus a weekly treatment gel will easily outperform a stack of nightly leave-on acids that leave your barrier inflamed.
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Hydrate and protect. Every acid, however gentle, increases your skin’s sensitivity to sunlight. Daily sunscreen is non-negotiable — even on grey British days. REFORM’s range of SPF 30 and SPF 50 sunscreens pairs naturally with an exfoliating routine. A solid barrier cream, used on off-nights, gives the skin crucial time to recover between treatments.
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Don't mix acids carelessly. Combining glycolic and salicylic acids in a single formula can be highly effective when properly balanced, but layering separate acid products yourself drastically increases the risk of irritation. A pre-built system like the Anti-Blemish Kit takes the guesswork out of this, ensuring the products work synergistically rather than competing.
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Listen to your skin. Tightness, stinging on application of otherwise gentle products, increased redness, and a sudden, waxy "shiny" look are all clear warning signs you’ve overdone it. Pull back to a gentle cleanser and barrier cream for a week or two before reintroducing acids far more sparingly.
The Bottom Line
There is no single "best" chemical exfoliant — only the best one for your skin at this moment. Glycolic acid delivers the most dramatic resurfacing and radiance, lactic acid offers gentle, hydrating exfoliation for reactive skin, and salicylic acid remains unrivalled for decongesting oily and blemish-prone complexions. Match the acid to your specific concern, start slowly, protect your barrier, and the results will speak for themselves.
