Are nail polish and salon chemicals a health risk?

What gets in, and how

Polish is a mix of solvents, film-formers and plasticizers. Triphenyl phosphate (TPHP) can serve as a plasticizer. In ten polishes bought in stores, TPHP made up as much as 1.68% by weight in eight, including two that did not list it. In 26 volunteers, urinary levels of its breakdown product (DPHP) rose nearly seven-fold 10 to 14 hours after painting. When volunteers instead painted synthetic nails fixed to gloves, so polish never touched their own skin, the marker was significantly lower. That points to skin as the main route⁷.

"Toxic trio" and "free-from" claims

Many brands dropped toluene, formaldehyde and dibutyl phthalate (DBP) and call themselves "3-free". In a chamber test of 20 such polishes by US occupational-health researchers, DBP and TPHP were not detected in any. Yet formaldehyde and toluene were measured in every one, with benzene also reported, while polish was applied to artificial nails². Hazard and exposure differ: a few minutes of vapor at home is not the same as an eight-hour shift.

Salon workers

• Air. In six Colorado salons, indoor toluene ranged from 26.7 to 816 micrograms per cubic metre, and formaldehyde exceeded a US occupational recommendation in one salon⁶.
• Body burden. Blood toluene in ten Boston technicians more than doubled over a work shift (median 0.158 to 0.360 micrograms per litre)⁸.
• Ventilation and masks. Three in four of 12 New York City salons missed minimum outdoor airflow rules¹. Workers' urinary TPHP and DPHP were higher after work, and masks lowered the amounts by about 77%⁹.

Gel manicures

Gel polish is cured under a UV lamp³ and often contains acrylates that can cause allergy⁵. Evidence that the lamps cause skin cancer is weak and the risk, if any, looks low³.

What to do

Customers: choose a ventilated salon, and an occasional manicure is not a reason for alarm. If you get gels often, protect your hands from the UV lamp³. Technicians: ventilation, gloves (skin is the main route for TPHP) and regularly replaced masks^7,9. See also Formaldehyde and Phthalates.

Polish itself

Mendelsohn and colleagues tested ten polishes purchased in 2013 to 2014. TPHP reached up to 1.68% by weight in eight, two of which did not list it. Two groups totalling 26 volunteers gave 411 urine samples before and after painting with a polish containing 0.97% TPHP. DPHP rose nearly seven-fold at 10 to 14 hours (p < 0.001). In ten volunteers who painted their own nails and synthetic nails fixed to gloves on separate days, DPHP was significantly lower when the glove blocked skin contact⁷. The exposure test used one brand, measured a urine marker rather than disease, and cannot say what repeated use does.

In the chamber test of 20 "n-free" polishes, geometric mean formaldehyde ranged from 0.021 to 0.273 ppm per gram of polish, toluene from 0.068 to 0.534 and benzene from 0.076 to 0.752. Levels did not differ significantly between products². No DBP or TPHP was found in any polish, so those claims held up; the formaldehyde and toluene claims did not.

Nail technicians

The Colorado study measured air in six salons and questioned 20 workers. Toluene ranged from 26.7 to 816 micrograms per cubic metre, benzene from 3.13 to 51.8, and formaldehyde from 5.32 to 20.6. Modeling a 20-year career, the authors estimated cancer risks above the US EPA's one-in-a-million benchmark for formaldehyde and benzene⁶. That is a modeled risk, not observed disease. In Boston, 10 technicians in seven salons had median airborne ethyl methacrylate of 240 and methyl methacrylate of 205 micrograms per cubic metre, and ventilation sometimes fell short of ASHRAE guidance⁸.

In the New York City study, the average total volatile organic compounds level was 29 ppm (SD 25). Methyl methacrylate, toluene and ethyl acetate were low to undetectable. Salons that met airflow rules had half the VOC level of those that did not (16 versus 33 ppm)¹. Workers in another study had urinary TPHP 5.2 times higher after work than before, and 19 and 13 times higher in two high-volume salons⁹. A scoping review of 42 studies, mostly with 20 to 150 workers, found inadequate ventilation in 71%, VOC levels above OSHA limits in some, and persistent methyl methacrylate despite an FDA ban. Only 17% examined exposure and health outcomes together¹⁰.

Health outcomes

California birth records from 1996 to 2009 showed little evidence of increased risk for most adverse birth outcomes in cosmetologists and manicurists. Small-for-gestational-age babies were more likely among Vietnamese manicurists (odds ratio 1.39; 95% CI 1.08 to 1.78). Manicurists had higher odds of gestational diabetes (1.28; 1.10 to 1.50) and placenta previa (1.46; 1.08 to 1.97) than the general population⁴. These are registry associations with no exposure data.

Gel nails and UV

In Amsterdam, acrylate nail cosmetics caused allergic contact dermatitis in 67 women, 1.6% of all patients and 2.3% of all women patch tested from 2015 to 2023. Of these, 97% reacted to HEMA, and 27% were professional stylists⁵. A systematic review of 12 reports covering 88 patients found allergy took on average 30 months to appear, and recorded three squamous cell carcinomas 11 to 15 years after UV exposure¹¹. A review of nine studies, many case reports, judged the skin cancer risk low but poorly measured³. In cell cultures, UV nail dryer radiation caused oxidative DNA damage and dose-dependent mutations¹², though cell studies do not tell us what happens on a hand with a few minutes of exposure.

Where the evidence is thin

Null or reassuring findings exist: most birth outcomes were not elevated⁴, and several chemicals were barely detectable in New York salons¹. No study follows ordinary customers for disease.

Bottom line

Confidence 2 of 5. Exposure to solvents, TPHP and acrylates is real and measurable, and highest for technicians. Evidence of harm at customer levels is lacking. Ventilation and gloves are the practical levers.