Related

Gel polish is not a lacquer. It is a photopolymerisable resin system: liquid acrylate monomers and oligomers plus a photoinitiator that, when it absorbs UVA light around 365–405 nm, generates free radicals and triggers rapid cross-linking. The liquid becomes a hard, solvent-resistant, cross-linked plastic in 30–60 seconds.

That cross-linking is why it does not chip, and why it cannot be removed with ordinary polish remover — it has to be soaked off in acetone, or the surface broken first so the acetone can get in.

Hydroxyethyl methacrylate (HEMA) and its relatives are the monomers doing the cross-linking, and uncured acrylate monomer is a potent skin sensitiser. Once sensitised, the reaction is permanent and can generalise.

What it looks like: itching, redness and swelling of the fingertips and nail folds; nail plate lifting and separation (onycholysis); and — because people touch their faces — eyelid and facial dermatitis with no obvious cause. Severe cases have caused permanent nail damage.

Two things drive it, and both are technique:

1. Product touching the skin. Gel must be kept off the cuticle and sidewalls. This is the single most important rule in the whole category.
2. Under-curing. An old lamp, a wrong lamp for the product, or too short a cure leaves monomer uncured and reactive on the surface.

The EU acted on this directly: Regulation (EU) 2020/1682 restricted HEMA and di-HEMA trimethylhexyl dicarbamate in nail products to professional use only, with mandatory warnings. There is no equivalent US restriction, and HEMA-containing gel polish is sold to consumers freely. HEMA-free formulations exist and are worth seeking out — though the alternative monomers are not automatically non-sensitising.

UV nail lamps emit UVA. The exposure per manicure is short, and expert assessments have generally concluded that the skin cancer risk from ordinary use is very low — though laboratory work reporting DNA damage in cells exposed to nail-lamp UVA has kept the question open, and the honest position is that this is not fully settled.

The mitigation costs nothing: fingerless UV-protective gloves, or a broad-spectrum sunscreen on the hands twenty minutes before the appointment. Given how cheap that is, there is no reason not to.

Peeling gel polish off takes layers of nail plate with it. That is the cause of the thin, weak, peeling nails people blame on the gel itself.

Proper removal: file the shiny top layer to break the seal, soak in acetone-wrapped cotton for 10–15 minutes, and gently push the softened product off. If it resists, soak longer. Never scrape a hard surface.

Cosmetic in the US — FDA primary category (10) manicuring preparations. Colour additives must be approved for the intended use, with certified colours from FDA-certified batches. There is no premarket approval and no US restriction on HEMA in consumer products.

In the EU, HEMA and di-HEMA TMHDI are restricted to professional use under Regulation (EU) 2020/1682, and permitted colorants come from the Annex IV closed positive list.

18–24 months. Gel polish is light-sensitive by design — it must be kept in an opaque bottle, capped, and away from sunlight and lamps, or it thickens and eventually cures in the bottle. A gel that has gone stringy or gritty is partly polymerised and should go.

• Nails — the shelf this sits on, and the rest of it.
• Cosmetics — what the label is legally allowed to say, and the full catalogue.
• The rest of Colour — Nail Polish · Dip Powder · Base Coat · Top Coat · Quick-Dry Drops.
• Acrylic Nails — the other methacrylate system, and the MMA problem.
• Regulatory statements here follow the FDA and EU sources listed on Cosmetics, read 16 August 2026.