HEMA, or hydroxyethyl methacrylate, is an acrylate monomer used in gel polish and nail enhancements that is a common cause of contact allergy, and EU law restricts it to professional use only.
Also known as: hydroxyethyl methacrylate, 2-HEMA, HEMA-free gel, acrylate allergy
Hydroxyethyl methacrylate (HEMA) is a small, reactive molecule that helps gel polish bond to the nail and cure into a hard film under a UV or LED lamp. It is a monomer: it links with other acrylates during curing. Any monomer left uncured, from a thin lamp, a thick coat or gel touching the skin, can sensitise the immune system.
Commission Regulation (EU) 2020/1682 restricted HEMA and Di-HEMA trimethylhexyl dicarbamate to professional use only. Products must carry the warnings For professional use only and Can cause an allergic reaction. The rule applied from 3 June 2021 for placing on the market and 3 September 2021 for making available (Scratch; Biorius). Professional products typically contain 4 to 35 percent HEMA, with 35 percent as the recommended ceiling.
A 2024 market survey in the journal Contact Dermatitis found widespread non-compliance among gel products sold to consumers online (Wiley). An at-home gel sold in the EU should therefore be HEMA-free and labelled as such; Dutch brand LAKKIE, for example, markets its cat-eye gel as HEMA and TPO free (LAKKIE).
An acrylate allergy shows as itching, redness and swelling around the nails, and sometimes on the eyelids or face where fingers touch. Once acquired it is lifelong and can affect dental and medical acrylics. See a dermatologist for a patch test if gel nails cause a rash. Air-dry lacquer contains no HEMA; its film is nitrocellulose, which is why people with an acrylate allergy can usually wear regular polish.