The Science of “3 Free” Nail Polish

I love nail polish. I hoard nail polish. On bad days, just gazing at my nails fills me with a sense of happiness and calm. As a scientist who experiences a lot of failure, discombobulation, and flailing, I NEED THAT CALM.

As a scientist, of course, I like to know the why of things. Which is why I was curious about the “3 Free” push made by many of the major nail polish brands, including OPI, China Glaze, Essie, Sally Hansen and many others. Let me tell you about what I found when I went searching for the back story regarding “3 Free,” the chemicals involved and what that means for you, the consumer:

“3 Free” refers to three ingredients that used to be included in most nail polishes: dibutyl phthalate (DBP), toluene and formaldehyde.

Dibutyl Phthalate-

DBP was included in nail polish formulas because it acted as a binder and improved the durability and the ability of nail polish to last a long time without chipping. Which, as anyone who polishes their nails can tell you, is a primary frustration with polish. However, general studies on this chemical (not performed specifically on nail polish) have shown that DBP has an effect of the in utero development of male sexual system in rats (1). There is also an effect during the pubertal sexual development of male rats and mice. In addition, DBP has been shown to antagonize the thyroid receptor (2). This means that DBP binds to the thyroid receptor and blocks the ability of necessary thyroid hormones to bind there.  This blockage of thyroid hormones to normally bind to thyroid receptors can have an effect on normal brain development. Studies have also been carried out on the effect of DBP on metabolism and liver function with negative results.

In humans, a study performed in Korea (3) linked phthalate exposure to intelligence levels in children. There was a limiting factor in this study, but there is a frightening correlation, meaning that increased phthalate exposure and decreased intelligence seem to occur in the same children when maternal IQ was controlled for. This does not mean necessarily that one caused the other, and more than one phthalate was looked at; all this means is that there is some cause for concern and more studies are necessary.


Toluene is a solvent that was used in many nail polish formulations to dissolve other ingredients and make a nice smooth, easy-to-apply polish. After application to the nail, toluene will volatilize, or evaporate and leave a smooth, glossy finish. Toluene is found naturally in crude oil and in the tolu tree.

According to the Centers for Disease Control, the effect of toluene on humans at low, environmental doses is unknown. However, short term, high load doses can result in poor performance on cognitive tests as well as eye and upper respiratory irritation. Chronic solvent abuse (such as huffing) can result in dementia and brain damage.

Nail color: MAC Demi Blanc. Courtesy of OneBigPear.

Formaldehyde resin-

Technically, nail polishes don’t contain straight formaldehyde, they contain a resin called tosylamide formaldehyde resin. This resin ensured that the polish adhered to the nail’s surface and made the polish tough and resilient. Interestingly, it seems that tosylamide formaldehyde resin (TS-F-R), is a major allergen and can cause contact dermatitis. In fact, TS-F-R can actually remain active and bioavailable for up to three days after painting your nails (4). A search through only turns up allergy references in regards to tosylamide formaldehyde resin, indicating that the resin likely doesn’t have the carcinogenic (cancer causing) properties of its cousin, formaldehyde.

Nail color: Zoya Edyta. Courtesy of Hermionedanger.

What have we learned? That DBP seems to be a pretty bad chemical, all the way around. Toluene may not be quite so bad for you, but the jury is out, given that more study is needed to study the effect of low doses. Formaldehyde resin seems mainly to cause allergic reactions, something crucial to know if you are predisposed to skin allergies or have contact dermatitis.

I, for one, am happy that many of my favorite nail polish brands have moved to a “3 Free” formulation. In recent years, more and more studies have emerged about the dangers of additives in everyday products. It is incumbent upon us to be proactive about knowing the science behind what we use every day and how it could harm us. Also, write to your congress people and express your support for NIH funding!

Did I make a mistake? Do you disagree with something I wrote? Have a question? Email me at!


Relevant and interesting references: – CDC information regarding DBP chemical, monitoring and the effect of exposure

1.)McKee et al. NTP center for the evaluation of risks to human reproduction reports on phthalates: addressing the data gaps. Reprod Toxicol. 2004 Jan-Feb;18(1):1-22.

2.) Li N. et al. Dibutyl phthalate contributes to the thyroid receptor antagonistic activity in drinking water processes. Environ Sci Technol. 2010 Sep 1;44(17):6863-8.

3.) Cho SC et al. Relationship between enviromental phthalate exposure and the intelligence of school-age children. Environ Health Perspect.2010 Jul;118(7)1027-32. Epub2010 Mar 1. – CDC information regarding toluene, monitoring and exposure

4.) Hausen BM et al. The allergens of nail polish (I). Allergenic constituents of common nail polish and toluenesolfonamide-formaldehyde resine (TS-F-R). Contact Dermatitis. 1995 Sep; 33(3):157-64.

121 replies on “The Science of “3 Free” Nail Polish”

Thanks so much for this article! I knew a bit about the formaldehyde resin before — My mother had a strange rash on her neck that turned out to have come from scratching her neck with newly painted fingernails! Here’s a challenge for you: There are some polish brands that now tout themselves as 4-free. What’s the fourth chemical?

P.S. I hadn’t been checking Perseph that frequently, but I saw your note on FB. :)

Thanks for putting this info together! I’m glad to find out that the brand I use (OPI) doesn’t use these chemicals. Ironically, I’ve found it to have the best staying power or any nail polish I’ve used.

That might be because I know it’s so expensive so I’m more careful about putting it on nicely (plus I’m older now and I need my manicures to last a week), but… either way, it works!

I think they smell a lot different too… I have some old non-3 Free polishes, but I don’t know what to do with them, since you’re supposed to dispose of them as hazardous waste where I live, rather than throwing them in the trash.

Which kinda freaks me out, when I think about it.

TheMAS, brands like Revlon and Sally Hansen, both available at Walgreens are 3 Free. Also, Essie, which is a salon brand polish, has lately been offered at WalMart. Essie is also 3 free. Happily, I stumbled upon a list that had already been compiled by the nail blog

You can find there a list of many of the 3 Free polishes, many of which you can likely pick up at your local drug store.

For anything not on the list, you’re going to have to check yourself.

I like nail polish. I like how it looks on other people. I have a slight compulsion to keep cutting my nails short, so nail polish looks quite ridiculous on me.

I liked the break down of the chemicals. I didn’t know that toluene was in nail polish. Speaking as a scientist, I’m always surprised to see chemicals I use in the lab in everyday life. Acetone, EDTA etc.

On a slightly nerdy note, nail polish is good for so many other things than painting nails. A ball of nail polish on a cord will help you figure out which side is up without having to look.

Great post; I had no idea about the “3 free” nail polishes, and you did an awesome job explaining what that means. I’m also happy that some companies are removing potentially harmful chemicals from their polishes. Do you know what kinds of other ingrediants they’re substituting to keep the polishes holding up well, etc? Or if there’s a noticable difference in how the polishes go on and look now?

I’ve recently switched to buying my nail polish from Zoya, which is all or almost all “3 Free,” and haven’t noticed a difference in terms of quality or staying power. Of course, I don’t do any fancy nails, just basics, but they go on and look the same.

The smell is a little different (probably the missing formaldehyde) and some, like Edyta, seem to take longer to fully dry (probably related to the thickness of the particular polish rather than any chemical differences). Overall, though, in terms of my experience with the 3 Free polishes’ performance they’re exactly the same as regular polish.

OPI went 3 Free a while ago – starting in 2006, I believe. Many of the other major salon brands went 3 Free a long time ago as well. Those brands have really nice application but I have to say that durability does seem a little shorter.

Brands that have gone three free more recently, according to various nail polish blogs that I read while writing this, seem to still be working out their formulation.

As for what other ingredients were added back, I have no idea. I searched for a while and I think they’re relying on ‘trade secrets’ at the moment.

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