Toxic Chemicals to Watch out for in Nail Polish

In the last decade or so, a number of more natural nail polish brands have popped up, promoting their products as ‘3-free’, ’10-free’, or similar. This means that the polish does not contain several of the toxic ingredients commonly found in nail polish. These brands, such as London Butter and Kure Bazaar, have grown in popularity, and other, better known, brands have followed suit. Are these nail polishes really any more natural and less toxic than their previous offerings, though? And which chemicals are the ‘big three’ or the ‘big ten’?

In general, nail polishes that are ‘3-free’ do not contain toluene, dibutyl phthalate (DBP), or formaldehyde, which are known carcinogens. Brands that are promoted as “5-free” go a step further and don’t use formaldehyde resin or camphor. Those that are ‘7-free’ don’t contain ethyl tosylamide or xylene. Still, many of these brands make polishes that contain a cocktail of other chemicals, so it’s important to read the labels.

To understand why these chemicals are in nail polish, it helps to understand how polish does what it does.

Skip to the cheat sheet for What You Need to Know About Eco-Friendly Nail Polish. You can also check out our top recommendations for glitter nail polish that are safe to use!

How does nail polish work?

• Nail polishes typically have very similar formulations. These comprise a film-former, a resin or secondary film-former, a plasticizer, and solvent(s).
• The film-formers, such as nitrocellulose or cellulose acetate butyrate, make the polish hard and shiny when it dries. The resin or additional film-former, such as a mixture of tosylamide and formaldehyde or epoxy resin adds toughness to the polish. The plasticizer(s), such as triphenyl phosphate, trimethyl pentanyl diisobutyrate, and dibutyl phthalate (DBP) help prevent chips and cracks in the polish, as does camphor.
• Finally, solvents such as ethyl acetate, butyl acetate, isopropyl alcohol, and toluene, help the polish go on evenly and smoothly. They also enable the polish to dry more quickly as these evaporate faster than water.

Most nail polishes also contain colorants and pigments. This usually means polish needs to include a suspension agent or clay, typically stearalkonium hectorite or bentonite. Colored nail polishes will also often contain a UV stabilizer to prevent the color from fading when exposed to sunlight. Benzophenone-1 is one of the most common UV stabilizers and is also found in sunscreen.

Some nail polishes or treatments contain additional chemicals. These confer specific properties such as conditioning nails, adding glitter, or to make polish taste bitter. I was a nail-biter as a kid and can confirm (shhh!) that not all kids find the taste of these bite-prevention polishes bitter. Thankfully, I stopped biting my nails even though I quite liked the taste of the nail treatment.

So, now we know the kinds of chemicals typically found in nail polish, what should we do with that information? Are all of these chemicals toxic? Does this mean we have to avoid all nail polish to avoid potentially unsafe chemicals? Not quite.

How troublesome are these toxic chemicals in nail polish?

It’s important to remember that nails, both toenails and fingernails, are made of a tough protein called keratin. This tissue is somewhat impenetrable, meaning that some of the things we put on it will not get absorbed into the nail bed and into the body. And, because nail polish dries pretty quickly, most of the chemicals in polish are not released into the air after the product is fully dry.

That said, keratin is not entirely impermeable. And, of course, the skin around your nails, and your cuticles, can also absorb undesirable chemicals. What’s more, some of the chemicals in nail polish actually make your nails more permeable and can sensitize the skin and nails so they react more to other chemicals. Fun!

You’re also likely to be in close proximity to your nails while painting them or having them painted. This means you’ll breathe in whatever off-gases from your nail polish. And we should spare a thought for those working day after day at nail salons, as these employees are subjected to significant exposure to chemicals.

The US Food and Drug Administration has issued specific health advice regarding common chemicals in nail products, including for formaldehyde and toluene. And, if you do have a reaction to nail polish, the FDA wants to know. That’s because the law does not require cosmetic companies to report complaints to the FDA. As such, consumer reports are an important source of information for the FDA to keep on top of problem cosmetics. To report health problems related to nail polish and other cosmetics, you can use FDA’s MedWatch system, online or by calling 1-800-FDA-1088, or contact the FDA consumer complaint coordinator for your geographic area.

Let’s look first at the three chemicals brands omit when they are ‘3-free’.

The big three toxic chemicals in nail polish

Formaldehyde

The FDA note that formaldehyde is often used in nail hardeners. This is because formaldehyde bonds with keratin to harden nails. The European Scientific Committee on Consumer Safety (SCCS) reviewed the use of formaldehyde in nail hardeners in 2014 and concluded that formaldehyde can be safely used up to 2.2% to harden or strengthen nails.

If you use this chemical too often on your nails, however, it can make nails brittle and may lead to breakage, splitting, and peeling. Frankly, if your nails are not as hard and healthy as you’d like and are prone to splitting, peeling, or breaking, you might want to look at your biotin intake and use a tried and tested biotin supplement instead of ‘treating’ them with a chemical that is a known carcinogen according to the International Agency for Research on Cancer.

A daily dose of 2500-5000 mcg of biotin has been shown in multiple studies to help improve nail hardness and health and reduce nail splitting and brittleness, in addition to supporting hair and skin health and overall metabolic health (R).

In addition to formaldehyde potentially making nails more brittle and painful, formaldehyde sensitivity is also common. This means that you may already be sensitive to formaldehyde or could develop an allergic skin reaction, eye irritation, or breathing difficulties and other symptoms if using products containing formaldehyde. Because it’s such a common chemical in household products, including clothing, bed sheets, mattresses, and more, I’ve covered the potential health effects of formaldehyde here on Leaf Score. Formaldehyde may be listed as formalin or methylene glycol or methyl aldehyde.

Some products aim not to strengthen the nail itself but to provide a strong coating. These products typically contain toluene sulfonamide and formaldehyde resin (TSFR). TSFR also helps the mail polish stick to the nail, adds gloss and helps the polish flow during application. You can also develop and allergy to TSFR. And, in TSFR, you not only have formaldehyde to contend with, there’s also toluene.

Toluene

More than three decades ago, the Cosmetic Ingredient Review Expert Panel determined that toluene was safe for cosmetic use in nail products when limited to concentrations no greater than 50 percent. This conclusion was reaffirmed in 2005 when the panel re-examined safety data. So, is toluene a non-issue in nail polish? Not quite.

Toluene is, like formaldehyde, a known carcinogen. It is a volatile organic compound (VOC) and has been linked to fertility problems and miscarriage, including serious harm to female reproductive health and to fetal and newborn development (R). Exposure to toluene during pregnancy may result in “intrauterine growth retardation, premature delivery, congenital malformations, and postnatal developmental retardation”, as well as “decreased late fetal weight and retarded skeletal development”, and possible kidney problems and neurobehavioral developmental issues in newborns.

So, yeah, I’d err on the side of caution and avoid using nail polish containing toluene if you are pregnant or trying to conceive.

And, to jump back to TSFR for a moment, in case you’re wondering if ‘tosylamide/formaldehyde resin’ (TSFR) is any better than toluene and formaldehyde in nail polish, it’s not. TSFR is simply a polymer formed from the reaction of toluene and formaldehyde. This chemical may also be listed as toluenesulfonamide/formaldehyde resin and is usually present in nail polish to make the film-forming nitrocellulose type polymers less hard and brittle. It still contains both toluene and formaldehyde, meaning it brings with it the risks associated with both chemicals.

Acknowledging the health concerns associated with formaldehyde and toluene, most members of the Personal Care Products Council (PCPC), who account for most US nail polish sales, have reduced or eliminated their use of these ingredients. The same goes for the plasticizer DBP, but not necessarily for other phthalates and plasticizers.

Dibutyl phthalate (DBP) and other plasticizers in nail polish

Dibutyl phthalate (DBP) is a commonly used plasticizer found in cosmetics and personal care products. Its presence in these products should not, however, suggest that it is entirely problem-free. Indeed, DBP is banned (along with five other phthalates) for use in soft vinyl children’s toys in Canada, because Health Canada considers there to be sufficient evidence to link DBP with liver and kidney failure in young children who would suck or chew on these toys and get exposure to DBP that way. Although Health Canada didn’t ban DBP use in cosmetics, it seems pretty obvious that nail polishes containing this chemical should not be used to paint infant or children’s fingers.

In the European Union, DBP is classified as a suspected endocrine disruptor and reproductive toxin. Again, this means it is best to avoid products containing this phthalate and most other phthalates if trying to conceive or while pregnant (and in general!). The EU also classifies DBP as very toxic to aquatic organisms, so even if you’re not too concerned for your own health, think of the fish!

In the US, based primarily on concerns over reproductive toxicity, Congress permanently prohibited children’s toys and child care articles containing concentrations of more than 0.1 percent of DBP and two other phthalates (DEHP and BBP) in the Consumer Product Safety Improvement Act of 2008 (CPSIA). And, despite significant lobbying, the CPSC adopted a final rule in 2018 prohibiting levels higher than 0.1 percent of eight other phthalates in children’s toys and child care articles. Unfortunately, nail polish is not among these products as nail products are regulated by the FDA.

Many companies now specify that their products are not just DBP-free but phthalate-free. This sometimes means that a nail polish contains camphor instead of other plasticizers.

Camphor

Camphor has long been used as a plasticizer to keep resins flexible and prevent chipping. This white, waxy, crystalline compound is naturally occurring and derived from the wood of the camphor tree, Cinnamomum camphora. It can also be synthesized.

Safety tests have confirmed that camphor is not carcinogenic or mutagenic in bacteria, but it is not without health concerns. Acute or chronic exposure to camphor may cause nausea, headache, shortness of breath, irritation to skin, nose, lungs, and eyes, central nervous system issues resulting in convulsions and breathing difficulties, and even death if camphor is ingested (R).

Health Canada allows camphor to be used in nail polish and cosmetics at concentrations less than or equal to 3% and it is generally considered to be of low concern in nail polish unless used improperly or present at very high levels.

Other plasticizers

Other plasticizers include trimethyl pentanyl diisobutyrate. This chemical is suspected to be an environmental toxin and to be persistent or bioaccumulative. It may also have systemic toxicity in humans, according to the EWG, based on limited data (R).

Acetyl tributyl citrate, as well as acetyl triethyl citrate, acetyl trihexyl citrate and acetyl triethylhexyl citrate are also used as plasticizers for film-forming in nail polish, as well as in some emollient creams for conditioning skin. These chemicals are esters of citric acid and may be derived from citrus fruits and other natural sources.

The FDA lists acetyl triethyl citrate and acetyl tributyl citrate as indirect food additives that may be used in adhesives and in resinous and polymeric coatings for polyolefin films (such as for food and medical use). The other esters mentioned above have been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel as safe as used in cosmetics and personal care products.

While they all sound pretty much the same, there are some significant differences in how all these esters behave. Acetyl triethyl citrate, for example, is a strong skin sensitizer, while acetyl tributyl citrate does not appear to sensitize skin. Still, at the levels used in nail polish, assuming the polish stays on the nail only, the CIR concluded that both acetyl triethyl citrate and acetyl tributyl citrate at concentrations up to 7% are unlikely to pose a risk for sensitization. They extended this conclusion to cover the other citrates as these have a similar structure (R).

That said, acetyl tributyl citrate was found in one cellular study using human cells to be just as toxic as butylated hydroxytoluene (BHT) and more toxic than tricresyl-phosphate (R). All in all, given that acetyl tributyl citrate does not appear to sensitize or irritate skin and is only toxic at concentration far above those possible when using nail polish correctly, this plasticizer seems far preferable to DBP or other phthalates.

Ethyl tosylamide

Ethyl Tosylamide is a mixture of isomers of toluene bound to ethanesulfonamide. It is also known as benzenesulfonamide, nethyl2methyl; n-ethyl toluenesulfonamide; and n-ethyltoluene-2-sulphonamide. In some cases, this chemical may contain formaldehyde.

Ethyl tosylamide is a film-forming plasticizer, making it useful in nail polish. It helps make nail polish flexible and durable, and also helps improve how well the polish sticks to the nail.

The FDA includes ethyl toluene sulfonamide (AKA ethyl tosylamide) on its list of indirect food additives and it may be used in adhesives and in resinous and polymeric coatings. However, it is restricted for use in cosmetics in the EU (in the form of tosylamide formldehyde resin) because it poses a high risk of eye irritation and skin irritation.

Ethyl tosylamide has a 3 rating from EWG, based on very limited data. This means that it may pose a low to moderate risk to human health, although there is currently not a lot to support a conclusion either way. There is currently no evidence that this chemical presents a risk to the environment.

Some recent studies appear to suggest that benzensulfonamide derivatives have various inhibitory effects on some enzyme systems and may be useful as pharmaceuticals for managing inflammation, infection, ulcers, lipid levels, and other health concerns (R, R)

In general, then, I’d just steer away from products containing this chemical, given that it is unnecessary and may pose a risk to health.

Triphenyl phosphate

Triphenyl phosphate is another chemical commonly found in nail polish, where it acts as a film-forming plasticizer. This chemical is restricted for use in the EU as it is very toxic to aquatic life and has long lasting adverse effects. It is also possibly an endocrine disruptor in humans.

Triphenyl phosphate may also be listed as phenyl phosphate or TPP or THPH and is also a flame retardant. This chemical is marked as a moderate hazard (5) by the Environmental Working Group for its reproductive toxicity, neurotoxicity, endocrine disruption, allergies and immunotoxicity, and for its toxic effects on the environment.

In one study, people who painted their fingernails with nail polish containing triphenyl phosphate had a nearly seven-fold increase in levels of a triphenyl phosphate metabolite in their urine 10-14 hours after applying the polish. Worryingly, the researchers in this study found the chemical in 8 out of 10 nail polishes, including two that didn’t include triphenyl phosphate on the ingredients list. The highest concentration in the polish was 1.68% by weight (R).

Other chemicals to watch out for in nail polish

Along with the big three, there are plenty of other chemicals in nail polish that you’d do well to avoid. There are also some chemicals that sound scary but pose little to no risk to health or the environment. And, there are others that may be just as bad, if not worse, than the big three.

Here are some of the most commonly listed ingredients in nail polish and a quick overview of their potential impact on health and the environment.

Xylene

With an 8 rating from the EWG (meaning high hazard), it’s no wonder xylene has, for the most part, been eliminated from nail polish formulations and other cosmetics. Part of the ‘5-free’ group of chemicals, xylene is a known toxicant to the nervous system and respiratory system, and, although data is limited, may be toxic to the skin, liver, kidney, and gastrointestinal system. It could also affect cardiovascular health, reproductive health, and other aspects of health.

In the EU, regulations limit how much xylene employees can be exposed to in the workplace, and the chemical is classified as a skin, eye, and lung irritant. Given that xylene is not routinely used in nail polish anymore, be wary of companies making a big deal of being ‘xylene-free’. Chances are that this may be a way of distracting from the toxic chemicals still in their formulas.

Benzophenones in nail polish

Benzophenone-1, as well as benzophenone-3, -4, -5, -9, and -11, are powder compounds made from 2-hydroxybenzophenone. They absorb, reflect, or scatter UV light, helping to protect products from deterioration. Benzophenone-1 and -3 are used in nail polishes and enamels and, along with the other benzophenones, in bath products, make-up, hair care products, and more. Benzophenone-3 and -4 are also known as oxybenzone and sulisobenzone and are common ingredients in sunscreens as they can protect the skin from harmful UV light.

The FDA has approved the use of benzophenone-3 and -4 as safe and effective for use in sunscreen, at concentrations up to 6% and 10% respectively. All of the benzophenones listed above have been assessed by the Cosmetic Ingredient Review Expert Panel as safe for use in cosmetics and personal care products, with the last update confirming this conclusion in 2002.

That said, studies have found that 97% of Americans have at least some oxybenzone (benzophenone-3) in their body (R), largely due to sunscreen use. When this chemical is washed off, it enters the water supply and is consumed by fish and other aquatic life. Some research suggests that it is linked to coral reef bleaching and toxicity in fish (R).

Oxybenzone also reacts with chlorine and can produce hazardous by-products that concentrate in places like swimming pools and water treatment plants (R). And most water filtration systems don’t remove this chemical or the by-products as it reacts with chlorine (R).

In one study looking at sunscreens, oxybenzone was the most common UV filter that caused a photoallergenic reaction (in 26.8% of volunteers). This was followed by octyl methoxycinnamate, benzophenone-4 and mexenone, methylbenziliden camphor and others (R). Oxybenzone is also an endocrine disruptor, and has been linked to Hirschsprung’s disease (R). Data suggests that oxybenzone has a weak estrogenic effect and potent anti-androgenic activity (R, R).

In one laboratory study, oxybenzone increased proliferation of human breast cancer cells (R). Other research suggests it may be a factor in endometriosis in humans (R). It may also increase the risk of premature birth of male babies and could cause lower birth weights for female babies (R).

The good news is that you can quickly decrease the level of oxybenzone in your body by avoiding toiletries containing this chemical. In one study, 100 adolescent girls who switched their regular personal care products for those free from oxybenzone had a 36% reduction in urinary levels of the chemical after just 3 days. It’s also worth noting that the girls’ levels of some phthalates, parabens, and triclosan also decreased by some 27-45% during this time. Those girls who used sunscreens containing oxybenzone prior to the study had a 52% decrease in urinary levels of the chemical at the end of the study (R).

In nail polish and sunscreen, benzophenone-3 may be listed as benzonenon-3 (BP-3), or 2-hydroxy-4-methoxybenzophenone, or oxybenzone. And, while it is unlikely you’ll get much exposure to this chemical through nail polish, its ubiquity across toiletries and personal care products means every little bit adds up. Choosing a nail polish free from this chemical is a good first step to eliminating toxic chemicals from your beauty routine.

While it’s not always present in nail polish, I did find it in a lot of formulations that were otherwise mostly free of toxic chemicals. So, it’s best to check labels carefully. You may also want to check your other toiletries for benzophenone-1. The EWG classifies benzophenone-1 as a moderate health risk (4) with endocrine disrupting activity and a propensity to cause skin irritation or allergic reaction (R).

Styrene/Acrylates Copolymer

Styrene/Acrylates copolymer is typically added to nail polish for color and may be listed as styrene butadiene copolymer, polystyrene, styrene copolymer, styrene resin, ethylbenzene, or vinylbenzene. While this ingredient is not likely to pose a serious health risk, it may contain residual traces of styrene, a possible carcinogen, as well as contaminants with other health effects.

Styrene can be toxic to red blood cells and the liver if ingested and is toxic to the central nervous system if inhaled, according to the EPA (R).

Butyl alcohol in nail polish

Butyl alcohol is an irritant chemical found in nail polish. This chemical can irritate skin, eyes, and lungs, especially in cases of workplace exposure. It is also a systemic toxin, and is marked as a moderate hazard (4) by the EWG. It is not the same as butyl acetate (see below) but is used to make butyl acetate. This is one to avoid if possible in nail polish.

Nail polish colors – in some cases

If you’re vegan or looking for a cruelty-free nail polish and a safe nail polish, it’s imperative to read labels. Pigments in nail polish are derived from animal, plant, and synthetic sources and can include:

• Cochineal – from crushed insects
• Pearl and guanine – made from fish scales and skin
• FD&C and D&C colors – from bituminous coal (coal tar); these are carcinogenic and tested on animals
• Plant sources – such as grapes, beets, turmeric, saffron, chlorophyll, annatto, and others
• Oxides – iron oxide, titanium dioxide, etc.
• Ferric ammonium ferrocyanide – may pose a hazard to the environment, but data is insufficient
• Bismuth oxychloride – a naturally derived colorant with an EWG rating of 1 and no associated health risks or environmental risks
• Mica – not necessarily toxic in itself, but its extraction is linked to child labor, poor working conditions and deaths, as well as environmental pollution

Look at most nail polish labels, and you’ll see things such as Red 34, D&C Red 7 AL Lake, or Violet 2. These numbered colors are usually types of monoazo color that can be either straight colors (dyes), lakes, or mixtures. Dyes dissolve in water and are usually made as powders, granules, or liquids. A lake is an insoluble salt form of the dye. Some examples include D&C Red 7 BA Lake, which contains barium, and D&C Red 7 AL Lake, which contains aluminum.

These lakes are common in blushers, face powders, and in nail polish because they have more intense color than natural products. They are subject to certification by the US FDA for use in cosmetics that are externally applied but are not permitted in products intended for use on the lips or eye area, which gives you some indication that the FDA considers these chemicals potentially problematic.

FD&C and D&C colors are also usually more stable and uniform than natural colors, can be blended together more easily, and don’t make your nail polish smell or taste of, say, crushed insects or beets. They’re also much easier to use in products that don’t contain enough moisture to properly dissolve a dye.

All of these colors are subject to safety evaluation and regulation by the FDA, making them one of the most heavily scrutinized elements of nail polish in the US. In general, then, the colors in nail polish are not a big cause for concern. That said, I would steer clear of Red 34 and Violet 2, and run any colors by the EWG database before buying.

Some nail polish companies only use natural colorants from food grade materials in order to ensure product safety even if the polish is consumed. My advice would be to look for nail polish colors and brands that are also sold in Europe, where problematic color chemicals are much more likely to have been banned or restricted.

Glitter

Glitter – love it or hate it, you can’t avoid it. The shimmery, shiny, gets-everywhere stuff is a popular ingredient in many nail polishes as well as eye shadow, lipstick, hair gel, and more. But, while glitter might seem fairly innocuous and is mostly associated with sparkly unicorns, mermaids, and other magical things, its composition is far from enchanting.

Glitter is made of dyed or aluminum-plated microplastic polyethylene terephthalate, with pieces measuring less than five millimeters across. These microplastics are small enough, then, to pass through water filtration systems. And guess where microplastics end up once you’ve wiped and rinsed off your nail polish? Yup, in rivers, lakes, oceans, and beyond.

Glitter loses some of its sparkle, then, if you consider that fish and other aquatic organisms, as well as birds, eat these microplastics. And, of course, some humans go on to eat fish that have eaten microplastics. Now, consider that microplastics can act as a vehicle for bacteria, and you’ve got a sparkly worldwide waterway for pathogens. There’s also the issue of toxic chemicals in plastics, including phthalates and other endocrine disruptors. And, sadly, seabirds who eat these microplastics may end up with a stomach or gut full of the stuff, leading them to die of starvation.

So far, glitter hasn’t gone the way of microbeads, which were banned in 2015 in the US after years of concern over these microplastics in shower gels and exfoliants entering the waterways. However, there is a growing awareness of the environmental and health impact of glitter and this has led to several companies developing eco-friendly, non-toxic glitter, which you could always add into nail polish for a little extra sparkle. Check out my recommendations for eco-friendly, non-toxic glitter and glitter nail polish.

Now we’ve covered a whole host of potentially toxic chemicals in nail polish, here are a few chemicals in nail polish that are a low concern or pose no health risk.

What not to worry about (as much) in nail polish

Stearalkonium hectorite

Made from bentonite clay, stearalkonium hectorite has an EWG rating of 1 (very low risk) and is generally considered safe for use in cosmetics including nail polish (R), although safety data is sparse. This substance is used as a non-surfactant suspension agent, meaning it helps to keep various chemicals in liquid form in nail polish without making the polish foam. There is some risk of contaminants being present in this clay product.

Titanium dioxide

Titanium dioxide is a naturally occurring mineral found in the Earth’s crust. It is white, opaque, and can refract light and filter ultraviolet light, making it a popular ingredient in cosmetics and in sunscreens. In powder form, and when inhaled, titanium dioxide is potentially carcinogenic. As such, it’s best to avoid loose and pressed powders that contain titanium dioxide.

There are some concerns over the use of nanoparticles of titanium dioxide in sunscreens, given the lack of safety data and the potential for absorption through the skin and possible health effects (R). In nail polish, however, this mineral is not in a nanoparticle form and is suspended in liquid, with no risk of inhalation or absorption. In general, if a product contains titanium dioxide, look to see if it has the Made Safe seal of approval (they only approve non-nano formulas) or specifies that it is non-nano on the label.

Butyl acetate and ethyl acetate

Ethyl acetate and butyl acetate are clear liquids with fruity odors. They are naturally occurring solvents found in many types of fruit, and they can also be synthetically produced. These chemicals are some of the better studied chemicals that crop up in nail polish and other toiletries. They are frequently used in the fragrance component of products and are used to dissolve film-forming nitrocellulose in nail polish.

The EWG gives butyl acetate a risk rating of just 1, based on data suggesting little risk to human health or the environment with this chemical. In some individuals, skin (eye or lung) irritation may occur, but typically only with excessive exposure from poor working conditions or improper use of products.

In the US, the FDA has granted butyl acetate Generally Recognized as Safe (GRAS) status for use as a synthetic flavoring substance and adjuvant. It is also permitted to be used as a secondary food additive as a solvent, lubricant, or release agent. The CIR Expert Panel concluded that both ethyl acetate and butyl acetate were safe as cosmetic ingredients in the present practices of use and concentration, with a 2006 re-examination of evidence supporting this conclusion.

Ethyl Acetate is the ester of ethyl alcohol and acetic acid. Butyl acetate is the ester of n-butyl alcohol and acetic acid. Other names for butyl acetate include: n-butyl acetate; 1-acetoxybutane; acetic acid, butyl ester; butyl ester acetic acid; butyl ester, acetic acid; butyl ethanoate; 1-butyl acetate; acetate de butyle (French); acetic acid n-butyl ester; butile (acetati di) (Italian); butyl acetate (Osha).

Nitrocellulose

Nitrocellulose is produced from cellulose, i.e. plant fiber, but it isn’t entirely natural. It is sometimes used as a delivery mechanism for over the counter drugs for warts, corns, calluses, and so forth. Also known as cellulose nitrate, this ingredient is one of the most common film-formers in nail polish, as well as in other coatings, films, ink and adhesives.

Nitrocellulose is typically derived from ground down cotton fibers nitrated to form an ester (R). This substance is then treated with either alcohol or water to form a wet powder. As part of nail polish, nitrocellulose has excellent sticking properties, meaning you polish will stay where you want it. It also offers strength and durability, and releases solvents fast, meaning your manicure dries faster. Nitrocellulose has the advantage of being semi-occlusive, meaning that it both protects your nails and lets them breathe.

There are no specific human safety concerns with nitrocellulose and it is approved by the FDA for use in food packaging and in cosmetics and personal care products. That said, the widespread use of nitrocellulose in industry, and improper disposal of old nail polish, can contribute to environmental contamination with this chemical. Plus, it’s almost certainly the case that the cotton from which the nitrocellulose is made will be grown conventionally, i.e. with a ton of pesticides and other troublesome chemicals.

Dimethicone and silicon polymer derivatives

Some nail polish contains dimethicone or other silicon polymers including: Amino Bispropyl Dimethicone, Aminopropyl Dimethicone, Amodimethicone, Amodimethicone Hydroxystearate, Behenoxy Dimethicone, C30-45 Alkyl Dimethicone, C24-28 Alkyl Dimethicone, C30-45 Alkyl Methicone, Cetearyl Methicone, Cetyl Dimethicone, Dimethoxysilyl Ethylenediaminopropyl Dimethicone, Hexyl Methicone, Hydroxypropyldimethicone, Stearamidopropyl Dimethicone, Stearoxy Dimethicone, Stearyl Methicone, Stearyl Dimethicone, and Vinyl Dimethicone.

While these can be a bit hard to pronounce, they are generally considered safe for use in cosmetics and are also common food additives, used as antifoaming agents. As silicon A group chemicals, some of these ingredients are naturally occurring. Others are synthetic.

As a whole, dimethicone and structurally similar silicon ingredients have been extensively reviewed by the CIR, the World Health Organization (WHO) and other bodies and found to be free from harmful effects on health. These polymers are likely too big (molecularly) to be absorbed by the skin, are not irritating to the skin, cause no allergic skin reactions (i.e. do not sensitize skin), have no carcinogenic effect, are not reproductive or developmental toxins, and are not mutagenic. As such, there’s likely no need to avoid this ingredient in nail polish.

Isopropyl Alcohol

Isopropyl alcohol is a regular feature in nail polish as it is a useful solvent. Also known as rubbing alcohol, isopropanol or 2-propanol, this chemical is considered safe for use under current conditions in cosmetic products. Both the FDA and the WHO have reviewed safety data for isopropyl alcohol and conclude that it does not present a serious health risk when used under normal conditions.

The EWG gives isopropyl alcohol a rating of 2 based on good evidence that it is generally safe when used properly. As with any alcohol, improper use can cause skin irritation and sensitization, or eye irritation, and breathing problems as well as liver problems if inhaled. As an ingredient in nail polish, this chemical poses little to no risk to health, but it’s still a good idea to avoid using nail polish containing this ingredient in an unventilated area.

How to choose safe, non-toxic, eco-friendly nail polish

Whew! If you just made it through a lot of chemistry (or if you just skipped to the end), you’ll probably want a summary to help you better identify safe, non-toxic, eco-friendly nail polish. Here goes.

In general, avoid nail polish that contains the following chemicals:

1. Toluene and related chemicals
2. Dibutyl phthalate (DBP) and other phthalates
3. Formaldehyde, formaldehyde resin, toluene sulfonamide and formaldehyde resin (TSFR)
4. Ethyl tosylamide
5. Triphenyl phosphate
6. Xylene, benzene, and related chemicals
7. Benzophenones (including oxybenzone), mexenone, Octyl methoxycinnamate, methylbenziliden camphor and related chemicals
8. Camphor
9. Butyl alcohol
10. FD&C and D&C colors, lakes, and coal tar colors
11. Glitters made with microplastics
12. Trimethyl pentanyl diisobutyrate
13. Acetyl triethyl citrate and acetyl tributyl citrate
14. Nanoparticle titanium dioxide (and other nanoparticles)
15. Ferric ammonium ferrocyanide

And, for the most part, don’t worry too much about the following ingredients in nail polish, but perhaps avoid them if at all possible:

1. Butyl acetate and ethyl acetate
2. Nitrocellulose
3. Dimethicone and silicon polymer derivatives
4. Isopropyl alcohol

Finally, you probably don’t need to worry much at all about the following ingredients in nail polish:

1. Stearalkonium hectorite and bentonite
2. Titanium dioxide (non-nano)
3. Ethically sourced mica and synthetic mica made with fluorphlogopite
4. Natural, edible, food-grade colors

OK, so now that you have a handy cheat sheet for what to watch out for in nail polish, let’s put this knowledge into action with Leaf Score recommendations for the best eco-friendly, non-toxic glitter and glitter nail polish.