A common gel nail ingredient has been banned – here’s what you need to know

Over the past few years, a spate of headlines and studies have called out various gel nail ingredients as potential red flags for our health. Most recently, those headlines have centred around one specific ingredient, TPO (Trimethylbenzoyl diphenylphosphine oxide), which is being phased out in the UK. TPO is a photoinitiator, a chemical compound that absorbs light from UV or LED nail lamps to initiate the curing process, hardening the gel polish and giving it a glossy, durable finish. Research on animals has shown that high levels of exposure to TPO could be dangerous to fertility and embryonic development. In 2020, one study found that male rats underwent “massive” changes to their testicles and reduced fertility, while females experienced disruption to their reproductive cycle. Another lab study found TPO to be toxic to human cells. TPO has since been categorised as a category 1B reproductive toxicant under European Union and UK regulations, though this is a precautionary measure. The studies used much higher dosages than typical exposure during nail treatments, and the actual exposure time is brief due to the chemical reaction consuming TPO. The European Union banned TPO in September 2023, and the UK followed suit, prohibiting new products with TPO from 15 August 2024, with pre-existing stock available until 14 February 2025. Alternatives like TPO-L are now widely used. While concerns about TPO are valid, experts like Dr. Derrick Phillips note that current formulations show little difference in finish or durability. Beyond TPO, UV/LED nail lamps emit low levels of UVA radiation, which may pose a low risk of skin cancer with repeated exposure, though long-term studies are needed. Dermatologists recommend minimising exposure by using SPF or gloves. Another concern is acrylates, such as HEMA, which can cause allergic contact dermatitis. The British Association of Dermatologists reported a rise in cases, and HEMA is restricted to professional use. Sensitisation to acrylates can lead to long-term skin reactions. Occasional gel manicures are considered unlikely to pose significant health risks, but frequent use warrants checking ingredients and taking precautions.