If your product touches human skin — a smartwatch, a fitness band, a medical patch, a senior GPS watch — there's a standard you can't ignore: ISO 10993, the international standard for biocompatibility.
Yet many hardware teams only discover it late, when a housing that looked perfect suddenly needs certification before launch. Here's the plain-English version.
What ISO 10993 actually checks
For a device in prolonged skin contact, three tests matter most:
ISO 10993-5 — Cytotoxicity.
● Does the material kill or damage living cells? Tested with MEM elution on L929 cell cultures.
ISO 10993-10 — Skin Sensitization.
● Does it trigger an allergic response over repeated exposure? Tested via the Magnusson-Kligman method.
ISO 10993-23 — Skin Irritation.
● Does it cause redness or inflammation? Tested by intradermal reaction under ISO protocol.
Pass all three, and your housing is documented as safe for the skin it sits on.
Why the housing — not just the electronics — matters
Teams obsess over sensors and battery life, then treat the metal housing as a commodity. But the housing is what's physically against the skin, all day, every day. If its coating fails cytotoxicity or triggers irritation, you get skin reactions, bad reviews, and returns — after you've shipped.
What this means when choosing a supplier
Ask for the actual test report, not the phrase "it's biocompatible." A supplier who has genuinely been through ISO 10993 can show you which coating passed, which lab ran it, and how they coordinated sample prep and documentation. One who hasn't will give you a vague answer — and your launch timeline will pay for it.
At Tingfeng, we've taken a senior-wearable aluminum housing through all three ISO 10993 tests (all passed, tested by CTI). If your product touches skin, we're happy to share what that process actually involves.