More Isn't Always Better—Why Top Dermatologists Are Warning Against Daily Hypochlorous Acid Sprays

Chances are, hypochlorous acid wasn’t an ingredient you’d heard of until a few years ago. It was a little-known beauty secret, something only those in the know would seek out in the baby aisles of Boots. But now? It’s everywhere, and it’s gradually made its way out of the changing bags and into handbags. Brands including Tower28, Prequel, Medicube and e.l.f. now have their own versions, and while TikTok is full of videos telling us to spritz it onto everything from post-workout skin to active breakouts, is it actually the miracle product it’s touted to be?

It’s easy to understand the appeal. Hypochlorous acid is said to calm inflammation, reduce bacteria and support everything from acne to eczema and rosacea – all while being kind to sensitive skin, which makes sense when it’s considered safe for newborns. But the ever-growing popularity also raises an important question: if it works by killing bacteria, can it tell the difference between the ‘bad’ bacteria it’s designed to treat and the ‘good’ bacteria that help keep skin healthy? We asked the experts to find out.

What Exactly Is Hypochlorous Acid?

“Hypochlorous acid is something your body makes naturally,” says consultant dermatologist Dr Sidra Khan. “It’s part of how your immune system fights off bacteria and infection. In skincare, it’s bottled as a stable liquid that works as a gentle antiseptic, calming inflammation and keeping bacteria in check when you spray or apply it to skin.”

And, long before it became a trending ingredient, it was those antiseptic properties that made hypochlorous acid especially useful in clinical settings. Dr Stefanie Williams, dermatologist and medical director at Eudelo, uses it to disinfect skin before carrying out certain procedures, and sometimes recommends her patients use it for a few days after ablative laser treatments or at-home hair epilation to help prevent infection. It’s also used in wound care, and because it’s generally less irritating (and less likely to sting) than alcohol-based disinfectants, it’s well tolerated by most people.

Of course, its ability to reduce bacteria while calming inflammation helps explain the growing appeal for concerns like acne, eczema and rosacea, but Dr Khan says the evidence here is much more limited. Most existing research looks at short bursts of use for a particular problem, rather than indefinite daily use on skin that’s otherwise healthy. That’s why she sees hypochlorous acid as a ‘possible adjunct rather than a replacement’ for established treatments.

Does Your Skin Need Hypochlorous Acid Every Day?

Despite what TikTok might have us all believe, experts agree that the average person doesn’t—and shouldn’t—be using hypochlorous acid in their daily routine. “For most people with healthy skin, there’s no evidence that adding a daily antimicrobial spray is necessary,” says Dr Khan. “The everyday essential positioning is more marketing than medicine.”

Dr Williams concurs, adding that she will always advise against using topical hypochlorous acid as part of a daily skincare routine. “My reasoning is simply because it’s an ingredient that has broad-spectrum antimicrobial properties, and overuse may disrupt physiological microbial communities on skin,” she says.

But what exactly does that mean? In short, using hypochlorous acid too often could disturb the balance of microorganisms that naturally live on, and help protect, skin. Together, they make up the skin’s microbiome, which supports everything from the skin barrier to its ability to defend itself against potential irritants and harmful bacteria. So, as Dr Williams says, why risk disturbing it unless clinically necessary?

Ultimately, the main concern is that hypochlorous acid may not be able to tell the difference between bacteria that we want to remove and those that support skin. “It doesn’t know the difference between ‘good’ and ‘bad’,” says Dr Khan. “It just kills whatever it comes into contact with. Wipe out too much of the good stuff too often and, in theory, you leave room for less friendly bacteria to move in and weaken the skin’s natural defences.”

However, the in theory is important, simply because there isn’t enough evidence to prove that using it every day will damage your skin’s microbiome. Dr Williams says that while low-strength formulas do appear to reduce harmful bacteria without having a significant effect on the good bacteria in the short term, nobody really knows what could happen after months of continuous use.

Should You Stop Using Hypochlorous Acid Altogether?

Not necessarily: it can be an effective, well-tolerated ingredient when it’s used for a specific reason. The main issue is the idea that everybody needs to use it every day. And as Dr Khan concludes: “The science is solid for specific situations, but the marketing has run well ahead of it, and it hasn’t earned its new status as a daily must-have for everybody.”

So, for now, think of hypochlorous acid as a useful targeted treatment to be used occasionally, instead of an everyday skincare miracle that social media has made it out to be.