Hypochlorous acid: the skincare ingredient you can buy for £3 in the baby aisle

Hypochlorous acid spray has been having a major moment in the skincare world, mostly off the back of Tower 28's SOS spray. And honestly, the science behind it is real. It's worth understanding.

HOCl is naturally produced by your own immune cells as part of your skin's defence response. Applied topically, it's antimicrobial and anti-inflammatory — it calms reactive skin, helps manage bacteria on the surface, and has some solid evidence behind it as a tool for rosacea-prone skin specifically. Dermatologists use it post-procedure to reduce redness and support healing.

So far, so good.

Here's the thing though. Tower 28's formula contains exactly three ingredients: water, sodium chloride (salt), and hypochlorous acid. That's it. There's a good reason for the simplicity — HOCl doesn't play well with other ingredients. It's reactive by nature, which is what makes it useful, and that same reactivity makes it difficult to combine with much else without destabilising it.

Which means the formula is, essentially, what it is. Clean, effective, and genuinely simple.

The exact same formulation — water, salt, hypochlorous acid — is sold in the baby care aisle for a fraction of the price. It's used to clean and sanitise baby skin and surfaces. The reason it's so gentle is the same reason it works on reactive adult skin. I use the Vital Baby Aquaint one.

If you're curious about HOCl and want to try it without spending £20 on the skincare version, just buy that. Same thing.

Micaela, Founder & Formulator / Neighbourhood Botanicals