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Acrylic Fingernails Harbour Interesting Chemistry

You may not realize it, but if you are wearing acrylic fingernails, you have experienced some fascinating chemistry.

I was queried via email “if there are chemicals in acrylic fingernails.†I imagine the question was really about the safety of the ingredients because for many the term chemical has become synonymous with toxic substance. Well, yes there are chemicals in acrylic fingernails, just like in everything except in a vacuum. As far as safety goes, it is possible to have an adverse reaction to some of the ingredients but that is not common. What there is for sure in acrylic fingernails is a lot of interesting chemistry.

Actually, there are two types of acrylic fingernails. You have the type that is made of acrylic and is attached to the fingernail with cyanoacrylate glue, which is also a type of acrylic. And you also have the gel type that is painted on to the fingernail and is hardened by exposure to ultraviolet light. That involves some fascinating chemistry with the polymerization actually taking place on the finger. 

This kind of a reaction is initiated by the formation of highly reactive molecular species known as free radicals. Once formed, a free radical adds to a molecule of ethyl methacrylate, which then becomes very reactive and adds to another molecule to form a “dimer†which then latches on to another “monomer,†and pretty soon all the small molecules are zipped into a long chain. You now have a hardened acrylic nail! But why do you have to sit with your fingers under an ultraviolet lamp? Because it’s the UV light that generates the initial free radicals that get everything started. Ultraviolet light is energetic enough to break chemical bonds, which is exactly what it does to a “photo initiator†that is incorporated into the mix. Under the effect of UV, it breaks apart into free radicals. These then start the cascade of reactions resulting in a polymer. Of course, ultraviolet light is energetic enough to break other chemical bonds as well, including ones in DNA. That’s why excessive exposure to the sun causes skin cancer. And that brings up an interesting question. Is there a risk of cancer by exposing the skin on the hands to ultraviolet light while waiting for the acrylic gel to harden? 

Some concern about this possibility was generated by two Texas dermatologists in a paper submitted to the Archives of Dermatology in 2009. They reported diagnosing skin cancer on the fingers of two women, aged 55 and 48, both of whom had had previous exposure to ultraviolet nail lights. The first one had a 15-year history of twice monthly UV nail light exposure, the second had about eight treatments in one year, but that was several years before the first cancer appeared. Such case reports are interesting, but they are not very meaningful statistically. Ultraviolet light cured acrylic nails have been popular for some twenty years with millions of women using them. Any significant risk of skin cancer on the hands would have already been noted epidemiologically. Actually, UV exposure from nail lights is quite small in comparison to exposure from other UV sources such as sunlight. Living in Texas exposes one to significant UV.

Calculations show that exposure from a nail lamp is equivalent to spending an extra 1.5 to 3 minutes a day in sunlight between salon visits, the time depending on whether the lamp has one or two bulbs. Basically, the two case reports do not make for a compelling case and should not cause panic. The time spent under the lamps just isn’t long enough to present a significant risk. It is also interesting to note that since the paper originally appeared there have been no further reports of skin cancers linked to nail lights. One would have expected other dermatologists who read the paper to chime in with case histories that they noted, as is often the case after such publications. No further reports have been published. So, there’s no need to fret about acrylic fingernails, at least not because of UV exposure. If anyone is concerned, there is a simple solution. Apply sunscreen to the hands before going to the nail salon.

In addition to the acrylic monomers and photo initiators, there are cross-linking agents, reaction accelerators, plasticizers and pigments. So, irritation and allergic reactions are always a possibility. However, the biggest risk is to manicurists who work all day long not only with the chemicals used to create acrylic fingernails but also with the chemicals in nail polish and nail polish remover. Acrylic powder can be inhaled as it is being applied and can cause respiratory problems. Phthalates, toluene and formaldehyde found in nail polish and solvents such as acetone and ethyl acetate in nail polish remover can also produce toxic reactions. Nail salons need effective air circulation and workers have to be educated on how to work safely with the chemicals found in nail products.


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