'It really does pack a punch' - Caroline Hirons just launched her most potent exfoliator yet

There are very few names in the skincare world that carry the same weight as Caroline Hirons. Long before ingredient-led routines became mainstream, she was the one cutting through the noise - demystifying formulations, calling out industry fluff and reshaping how many of us approach our skincare altogether (hello, double cleansing).

Her advice is famously no-nonsense; it gets straight to the point and, more importantly, it just makes sense. In her book, Skincare: The Ultimate No-Nonsense Guide, she likens applying eye cream over moisturiser to wearing a bra over a T-shirt - a visual that’s hard to forget. It’s that ability to translate complex routines into something instantly understandable that has earned her such lasting trust.

That same clarity underpins her skincare line, Skin Rocks, which has always championed a barrier-first approach while still delivering on results. The Gentle Acid quickly became a go-to for regular exfoliation, and now, she’s expanding on that with The Strong Acid, a more intensive formula designed for those looking to take things a step further. True to form, it also comes with a clear message: this is not one for beginners.

Everything you need to know about Caroline Hirons' latest skincare launch

What makes The Strong Acid different from your typical exfoliating acid?

As the name suggests, The Strong Acid doesn’t hold back. It contains a high concentration of skincare acids (over 15%) and is formulated at a deliberately low pH, making it more potent than your average acid toner. “We wanted a clear differentiation between The Strong and Gentle Acids - not to scare people off, but to be clear that it really does pack a punch,” says Hirons.

Rather than relying on a single acid, the formula combines seven to tackle multiple concerns in one step. “Using five different AHAs means we can target dullness, texture, uneven skin tone and fine lines from different angles, supported by the PHA, which helps to increase hydration too,” she explains.

There’s also a BHA (salicylic acid) in the mix to help clear congestion and refine pores - so if you’re dealing with both dullness and the occasional breakout, it covers both bases. “If your main concern is dullness or texture, but you experience the odd breakout, this formula will work wonders for your skin,” seconds Hirons. Expect brighter, smoother-looking skin from the first use, with results building over time.

Who should (and shouldn’t) be using a high-strength acid like this?

“Anyone who has never used an exfoliating acid before or who is an irregular user of acids should not use The Strong Acid, and it’s certainly not for anyone with sensitive or sensitised skin,” says Hirons. The Gentle Acid is designed for the average user, whereas The Strong Acid is specifically for more experienced skin.

“If you have used acids containing AHAs regularly in the past without any irritation and are looking for a stronger formula, you can try The Strong Acid,” she continues. A slight tingling sensation is normal due to the low pH, but it shouldn’t sting or burn. “If you do experience any prolonged stinging, burning or redness, stop all acids until your skin has returned to normal,” she advises. If you’re unsure, patch test first - ideally on the forehead, where skin tends to be less reactive.

For those concerned about disrupting their skin barrier, Hirons is clear that strong actives and barrier care can co-exist. “There will always be a place, and a need, for both,” she says, adding that her approach remains firmly barrier-first - something reflected in every Skin Rocks product, which includes guidance on who it isn’t suitable for. As she puts it, “we’re still the only brand that will tell you not to use our product on our packaging.”

Why exfoliating becomes more important for midlife skin

From our 30s onwards, skin cell turnover begins to slow, which can lead to dullness, uneven texture and a loss of radiance. This is where exfoliation becomes more impactful - helping to shift the build-up of older skin cells and reveal fresher, brighter skin underneath.

When it comes to application, The Strong Acid isn’t designed for daily use. Instead, introduce it gradually (up to three times a week in the evening) - sweeping it over the face and neck with a cotton pad and avoiding the eye area. By removing that top layer of dead skin, it allows the rest of your routine to absorb more effectively, although it’s best to avoid using it alongside retinoids on the same night.

“This is the acid that I use in my own routine,” says Hirons. “If you want resurfaced, renewed and glowing skin, this is the one.” With continued use, expect smoother, brighter and more even-looking skin - just don’t skip SPF!