If you have ever used hypochlorous acid (HOCl) sprays for cleaning, sanitizing, or skincare, you may have asked yourself: does hypochlorous acid cause rust? In a nutshell: yes, it can under certain conditions. Let's find out why rusting occurs, what to look out for, and how to use HOCl safely without worrying about rusting before you start to worry about your cleaning sprays or skincare products ruining surfaces.
Why Hypochlorous Acid Can Cause Rust
When iron or steel is exposed to oxygen and moisture, oxidation takes place, leading to rust. While hypochlorous acid is extremely safe for natural surfaces and skin, it is still a weak acid with mild oxidizing properties. It can accelerate the rusting process when it comes into contact with metals like steel or iron, especially over time.
This doesn’t mean HOCl is inherently “corrosive” in the way bleach or harsh chemicals are—it’s far gentler. But if you leave metal tools, springs, or nozzles sitting wet with HOCl, rust formation is definitely possible.
Does That Mean HOCl Skincare Products Are Unsafe?
Certainly not. Reputable hypochlorous acid sprays, such as Honeydew Labs’ Hypochlorous Acid Spray, are made with a pH balance of about 5.5 and come in bottles that are made to prevent coming into contact with metal parts.
A brownish, rust-like buildup around spray nozzles is typically the result of a tiny metal spring inside the nozzle reacting with HOCl over time. The material and structure of the container is more important than the product formula; the solution itself is still safe to apply to skin.
To lessen these problems and maintain the formula's stability and effectiveness, Honeydew Labs uses specialized packaging.
How to Use HOCl and Avoid Rust
Here are a few easy pointers:
HOCl sprays should be stored in a cool, dry location away from heat sources and direct sunlight. Stay clear of prolonged metal contact: HOCl should not be left on steel surfaces or put into uncoated metal containers.
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Clean nozzles: Use a fresh tissue to gently wipe the spray head if you notice any residue building up around it. Select high-quality packaging: Seek out companies (like Honeydew Labs) that are aware of HOCl's stability and put it in long-lasting bottles.
Where HOCl Shines
Hypochlorous acid is still one of the most adaptable and skin-friendly antimicrobial solutions available, even with the rust issue. It is:
- Gentle enough for sensitive skin (great for acne, rosacea, and irritation)
- Effective against bacteria and impurities without harshness
- Multi-purpose (used in skincare, wound care, even food safety and veterinary care)
If you’re looking for a safe, everyday option, our Honeydew Labs Hypochlorous Acid Spray is dermatologist-inspired, fragrance-free, and packaged with stability in mind.
Final Takeaway
When hypochlorous acid comes into contact with metal components for an extended period of time, it can cause rust, but most people don't have to worry about it if they store and package it properly. HOCl is one of the mildest solutions on the market, safe, and effective for daily use on the skin.
If you want to experience the benefits without the drawbacks, stick with Honeydew Labs Hypochlorous Acid Spray—carefully designed to stay stable, safe, and effective.
After understanding how hypochlorous acid interacts with metals, you might be curious about its effects on skin — can you use hypochlorous acid as deodorant?
References
- Block, M. S., & Rowan, B. G. (2020). Hypochlorous acid: A review. Journal of Oral and Maxillofacial Surgery, 78(9), 1461–1466. https://doi.org/10.1016/j.joms.2020.05.044
- Wang, L., Bassiri, M., Najafi, R., Najafi, K., Yang, J., Khosrovi, B., … Robson, M. C. (2007). Hypochlorous acid as a potential wound care agent: Part I. Journal of Burns and Wounds, 6, e5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2094923/
Written by
Honeydew Labs Team
