As the Spring Festival approaches, the flavor of the New Year is getting stronger, and the nail salon has also ushered in the "highlight moment" of the year. For the sake of the beautiful New Year, many girls have arranged for themselves to wear "New Year's armor" early. However, since it is the peak period of nail art before the Chinese New Year, many people complain that nail art has encountered a situation where it has become more expensive and cannot queue up at all. Do you want to do the "New Year's Armor"? Will regular manicures bring health risks to me? How can you protect yourself while pursuing beauty? Let's make it clear in today's article. 
Manicure. **Author AI generated.
Is nail polish gel really safe?
People who do nail art regularly should have heard the opinion that "nail polish glue is used in nail salons, which is different from nail polish, does not contain formaldehyde, and is not toxic". However, this is not the case. Nail polish gel is relatively safe for normal use, but it is not completely non-toxic. The main components of nail polish glue are resins, photosensitizing initiators, and various additives (such as dyes, antioxidants, stabilizers and softeners, solvents), etc. Among them, organic solvents such as acetone and ethanol are often used to adjust the viscosity and fluidity of nail polish glue, but they may volatilize during use and have an irritating effect on the respiratory system and eyes. However,In order to save costs, some brands will use materials that are harmful to the body, such as formaldehyde resin. In 2015, the Hangzhou Municipal Consumer Protection Committee tested 10 kinds of nail polish glue and 5 kinds of nail polish products on the Hangzhou market, and in the test of volatile organic solvents, all 15 batches of toluene and ethylbenzene were detected, and the detection rate of xylene also reached 93%. Some batches were even detected with lead, styrene, and cumene. In the 2023 national cosmetics sampling inspection work, Zhejiang and Guangdong also had 7 batches of cosmetics inspection results that did not meet the requirements, and banned raw materials such as methylene chloride and 1,2-dichloroethane were detected. Long-term exposure to these ingredients may cause many serious health problems, such as long-term exposure to toluene, ethylbenzene, xylene, may cause respiratory irritation, respiratory tract inflammation, coughing and wheezing, and other problems; Formaldehyde, benzene, and acetaldehyde, among others, are considered potentially toxic and carcinogenic. In addition, there are still potential risks to the nail salon environment. In 2019, Lupita Montoya and Aaron Lamplugh of the University of Colorado Bode and Colorado State University jointly surveyed 6 nail salons in Colorado. They regularly measure the level of volatile organic compounds in the air in these stores. Shockingly, nail salons contain levels of possible carcinogens such as benzene, toluene, and xylene, far exceeding the standard limits, and even comparable to those of oil refineries and auto repair shops. In the case of benzene, the average benzene content in the air in one store reached about 518 g m3, well exceeding the US safety threshold standard (30 g m3). This is not an isolated case, as a team of researchers from Iran's Shahid Behshdi University of Medicine also found that levels of (probable) carcinogens such as benzene, formaldehyde and acetaldehyde were also significantly higher than outdoor concentrations in 20 nail salons surveyed. Another study conducted in Michigan**, USA, found that the concentration of toluene in nail salons was 30 times higher than outdoor levels. According to a survey by Lupita et al., 70% of nail salon clerks have experienced short-term health symptoms related to this, including headaches, allergies, eye irritation, etc. Therefore, although nail polish gel is relatively safe under normal conditions of use, consumers should remain vigilant and choose reputable brands and products. Make sure to use nail polish gel in a well-ventilated environment and try to avoid prolonged exposure to the smell of organic solvents. 
Nail salons can contain far more volatile organic compounds in the air. Source: Ref. [1].Nail light exposure can damage DNA
Since nail polish glue dries much slower than nail polish, nail salons often use UV nail lamps to cure gel nails in a short period of time, without having to wait for the nail polish to dry naturally. However, nail light exposure can be harmful to us. In 2009, two healthy women who had regular manicures and no family history of **cancer suddenly developed **cancer on their hands, and these two unique case studies sparked researchers' attention on nail lights. First, let's understand how nail lights work. UV nail lamps typically consist of multiple light-emitting diode (LED) bulbs. These bulbs are capable of emitting ultraviolet light with wavelengths between 365nm and 405nm, which is used to activate the photoinitiator in nail polish gel. Ultraviolet light (ULT**IOLET, or UV) is electromagnetic radiation with wavelengths ranging from 10nm to 400nm, located outside the violet portion of the visible spectrum and invisible to the human eye. In nail lamps, in order to indicate that the instrument is working, a common method is to use a separate violet lamp to emit violet light. 
Ultraviolet nail lamp. **Authors' AI-generated photoinitiators can absorb these specific wavelengths of UV light energy, which can initiate polymerization or crosslinking reactions in oligomeric resins in nail polish adhesives. These two chemical reactions cause new chemical bonds to form between the molecules in the gel or coating material, forming a polymeric structure that allows the gel to cure quickly, harden into a hard, and long-lasting state. This "light-curing" technology has the advantage of being environmentally friendly and fastThere are applications in many fields, such as 3D printing, painting and printing of materials such as metals and plastics, packaging of electronic components, etc. 
UV light curing principle. High dose exposure to UV rays in China LEDs has been widely recognized as a cause of cancer, so can UV light from nail lamps cause this consequence? In 2013, Julia Curtis and others at the University of Utah in the United States discovered that the dose of ultraviolet radiation emitted by UV nail lamps was 4 of that of the sun2x. The data statesIn less than 10 minutes of manicure, your hands receive the same dose of UV radiation as the recommended dose for a day of outdoor work. 
Comparison of spectral emissions of the sun (black line) and nail lamp (yellow line) (**Ref. [5]) Recently, Ludmil B. Aleksandrov of the University of California, San Diego and the University of Pittsburgh in the United StatesAlexandrov et al. give some molecular genetic evidence that nail lamp exposure may cause damage to us. Aleksandrov irradiated mouse and human cells with a UV lamp, and after two 20-minute irradiation (1 hour apart), approximately 20% of the cells died; If irradiated for 20 minutes a day for three days, 70% of cells died. And, the surviving cells show signs of DNA damage and mutations associated with cancer. While these results do not directly prove an increased risk of cancer, frequent nail light exposure does indicate that there may be a considerable risk. Aleksandrov et al. called for epidemiological studies to step in to further evaluate the physiological and carcinogenic effects of high-dose UV exposure on humans, which could take at least a decade to complete. So, how do you protect yourself while pursuing beauty? Reduce the frequency of manicures. Melissa Piliang, a doctor at the Cleveland Clinic in the United States, believes that three or five times a year is a safer frequency.
Choose reputable brands and products. Learn to read the ingredient list and choose a safer water-soluble nail polish or nail patch.
Make sure to use nail polish gel in a well-ventilated environment and try to avoid prolonged exposure to the smell of organic solvents.
There are some precautions that can be taken when getting a manicure, such as wearing protective gloves and applying sunscreen makeup, to reduce potential damage to the hands.
References
1] lamplugh, aaron, et al. "occupational exposure to volatile organic compounds and health risks in colorado nail salons." environmental pollution 249 (2019): 518-526.
2] hadei, mostafa, et al. "indoor concentrations of vocs in beauty salons; association with cosmetic practices and health risk assessment." journal of occupational medicine and toxicology 13 (2018): 1-9.
3] zhivagui, maria, et al. "dna damage and somatic mutations in mammalian cells after irradiation with a nail polish dryer." nature communications 14.1 (2023): 276.
4] bollard, stephanie marie, et al. "skin cancer risk and the use of uv nail lamps." australasian journal of dermatology 59.4 (2018): 348-349.
5] curtis, julia, et al. "acrylic nail curing uv lamps: high-intensity exposure warrants further research of skin cancer risk." journal of the american academy of dermatology 69.6 (2013): 1069-1070.
Planning and production
*丨Popular Science China.
Author丨Denovo Science Team.
Review丨Tang Qin, Director of the Science Popularization Department of the Chinese Medical Association, Researcher.
Planning丨Ding Kun.
Editor-in-charge丨Ding Kun, Zhong Yanping.