Buzzy Beauty Ingredient of the Moment: Hypochlorous Acid

Welcome to our series "Buzzy Beauty Ingredient of the Moment," the premise of which is pretty self-explanatory: In each installment, we'll explore an ingredient that's currently trending in the industry, springing up in a variety of different products lining the beauty aisle. We'll consult experts to find out about the science behind it — and why it's having a major moment right now.

Skin-care shelves are already overflowing with hard-working acids — we're talking hyaluronic, glycolic, salicylic, mandelic and lactic among many, many others. And the beauty industry (and much of #SkinTok) has recently welcomed another into its ranks: hypochlorous acid. Giving "clean" skin care a new meaning, this antibacterial acid that doubles as a gentle disinfectant has quickly been anointed as a healing solution for a host of skin issues. For all the "My Big Fat Greek Wedding" fans out there, Tower 28 Beauty's founder and CEO Amy Liu dubs it the "Windex of skin care."

Since the word "acid" (not to mention Windex) may strike fear in the hearts of the sensitive-skin crowd, it might be comforting to know we actually already have hypochlorous acid swimming through our veins: It's created by white blood cells as the first line of chemical defense against infections and bacteria. Basically, it attacks anything gross and unwanted to keep our immune systems running smoothly. It follows the same concept when applied topically, targeting inflammation and lingering bacteria on the skin.

"Hypochlorous acid has antimicrobial properties that can help to cleanse and even disinfect the skin," Dr. Sam Ellis, a board-certified dermatologist and the founder of skin-care brand Prequel, tells Fashionista. (The brand features the ingredient in its Universal Skin Solution Dermal Spray.) "It can also be used for anti-inflammatory purposes and for wound care. I use hypochlorous acid countless times a day to prep my patients for in-office injectable treatments and laser resurfacing."

Hypochlorous acid is quite the overachiever when incorporated into skin care: The naturally-produced compound fights acne, eczema, rosacea, sunburn, diaper rash, body odor, scrapes and cuts. Within a skin-care routine, it can also play many different roles, like serving as a skin-balancing first step or an as-needed refresher. "Think of it as a replacement for your toner — it will balance your skin's pH levels and promote skin health," Liu advises.

New York-based board-certified dermatologist Dr. Nkem Ugonabo recommends spritzing hypochlorous acid on after a sweaty workout or after a long trip "as a temporary solution until you can shower." (Because who knows what bacteria is lurking in those airplane cabins.) Plus, it can even be applied over makeup for a refreshing mid-day boost.

The ingredient itself is nothing new. Far from it, actually: French chemist Antoine Jérôme Balard discovered it in 1834. But why are hypochlorous acid skin-care products (most commonly bottled in spray formulas) popping up across the beauty industry now?

"I think there's an increasing demand for effective-yet-gentle skin care, as well as a shift toward research-backed, 'clean' ingredients," says Liu. "Hypochlorous acid checks all of those boxes. It's effective without being stripping or harsh, it's so research-backed that it's actually used in hospital settings to help speed up healing for post-op patients, it's found naturally in your body and [Tower 28's] SOS Rescue Spray in particular only consists of three simple ingredients."

When it comes to the hypochlorous acid sprays available on the market, many are just that: hypochlorous acid solutions, diluted to be safely applied to the skin. As Liu notes, Tower 28's SOS Daily Rescue — one of the more prominent sprays in the hypochlorous acid conversation — contains just three ingredients: water, sodium chloride and hypochlorous acid. Others have packed their solutions with extra skin-care ingredients: Peace Out's Redness + Clarifying Facial Mist is formulated with a hypochlorous acid blend backed by zinc, arnica and a trio of clays (bentonite, kaolin and montmorillonite) for reducing redness, while Clearstem's SkinSpray All Day also uses magnesium PCA and peptides to promote a hydrated, firmer-looking complexion.

Hypochlorous acid's versatility is its skin-care superpower, though it does have a kryptonite: It doesn't necessarily play well with all other ingredients. "It can inactivate antioxidants, so it's important to allow it to dry down before layering on skin care like vitamin C," Dr. Ellis notes. Hypochlorous acid fights bacteria through oxidation, so antioxidants such as vitamin C and some retinols may be rendered ineffective if used too closely together.

Dr. Ellis advises giving the spray a minute to sink into the skin before applying any actives. Liu even recommends a quick experiment to check that the hypochlorous acid spray isn't clashing with a vitamin C product: Spray a cut apple with hypochlorous acid, and then apply vitamin C after a minute. If the apple doesn't turn brown (i.e. oxidize), then the vitamin C is working.

Dr. Ugonabo notes that there are "very few downsides" associated with hypochlorous acid and that most skin types can use it without issue, but she still recommends trying a test spot before applying widely to ensure it doesn't cause any unwanted irritation.

"I think this has been a slept-on ingredient," Dr. Ellis says. "There are so many incredible uses of hypochlorous acid and it comes in such an easy-to-use way — a spray (like our Prequel Universal Skin Solution). It's an easy on-the-go solution that helps address a wide variety of skin issues. It's also incredibly gentle and non-irritating, which makes it particularly great for sensitive skin."

Ahead, we've rounded up the overachieving hypochlorous acid sprays targeting a myriad of skin issues.

Tower 28 Beauty SOS Daily Rescue Facial Spray with Hypochlorous Acid, $28, available here

Prequel Universal Skin Solution Dermal Spray, $17, available here

Youzu Daily Refresh Spray, $24, available here

Magic Molecule The Solution, $32, available here

Peace Out Redness + Clarifying Facial Mist with Hypochlorous Acid Blend, $28, available here

Base Laboratories Hypochlorous Acid Spray, $16, available here

Clearstem SkinSpray All Day, $38, available here

Briotech Topical Skin Spray, $17, available here

Enhanse Super Clean, $28, available here

Undefined R&R Repair Mist, $18, available here

Hydrinity Hyacyn Active, $60, available here

Lomalux Eczemol OTC Topical Eczema Spray with Hypochlorous Acid, $23, available here

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