Gel manicures and acrylic nails are commonplace in fashion, but these popular accessories come with health risks. From nail glue to formaldehyde, there are substances to look out for.

“While manicures might feel like self-care, they can ruin healthy natural nails — and might even cause unexpected health problems in a small proportion of people who get them,” Adam Taylor, professor and director of the Clinical Anatomy Learning Centre at Lancaster University, told the Conversation. “For example, the nail glue used to attach acrylics to the natural nail is typically a mixture of alcohol, cyanoacrylate and photo-bonded methacrylate, with other ingredients including formaldehyde, which is a known carcinogen.”

According to the U.S. Occupational Safety and Health Administration, the dangerous chemicals present in a nail salon can be especially dangerous to salon workers.

“These exposures can ‘add up,’ especially when many products are being used at the same time, the products are used day after day, or when there is poor ventilation in the salon. When this happens, workers can get sick,” the administration said. “Many nail salon workers also work long hours, which adds to the amount of time they may be exposed to chemicals.”

Nail adhesives also can cause skin irritation and dermatitis, in addition to burns. Nail polish remover can cause headaches, dizziness and irritation to the eyes, skin and throat. Fingernail glue remover can cause nausea, vomiting and exhaustion. Formaldehyde, sometimes used in nail polish, can cause asthma-like attacks, allergic reactions and more.

Chemicals used in artificial products, primer, hardener and artificial nail liquid can cause loss of smell, burns, difficulty breathing, irritation to the skin and other conditions.

“Prolonged wearing of gels and acrylics can also lead to pseudo-psoriatic nails, where extra-skin — known as hyperkeratosis — growing under the nail resembles the red and crusty appearance of psoriasis,” Taylor added. “Many manicure enthusiasts with pseudo-psoriatic nails test positive for allergy to methyl methacrylate.”

The allergic reaction can sometimes cause the wearer to permanently lose their fingernails.

To avoid the health risks, Taylor suggested sticking to natural nail care and leaving the gels/acrylics behind.