Non-Toxic Nail Polish: What “3-Free” Really Leaves Out

“3-free,” “5-free,” “10-free”: nail polish packaging loves a number. The trouble is that the number only counts the ingredients the brand chose to leave out, and one of the best-studied ingredients in polish is usually not on the list. That matters if you are shopping for non-toxic nail polish.

One note up front: we have not scanned nail polish ourselves. Our 133 scans (September 23 – October 5, 2026) covered other products, so everything below comes from published research and regulator lists, not our own data.

The TPHP study

Triphenyl phosphate (TPHP) shows up in nail polish. In a 2016 study in Environment International (Mendelsohn et al., from Duke University and the Environmental Working Group), researchers found TPHP in 8 of 10 polishes they tested, at up to 1.68% by weight.

They also measured what happened afterward. Participants had their nails painted, and a urinary metabolite of TPHP, DPHP, rose nearly sevenfold 10 to 14 hours later. The researchers concluded that exposure came mostly through the skin.

What that does and doesn’t mean: it shows TPHP from polish gets into the body. It doesn’t show harm from a manicure. But TPHP is on the EU’s endocrine disruptor List I, the group of substances identified as endocrine disruptors at EU level, so it’s on our hormone list for a reason. (Lists are maintained at edlists.org by the Danish EPA for Belgium, Denmark, France, the Netherlands and Spain.)

What “3-free” means

“3-free” means the polish leaves out three things: dibutyl phthalate (DBP), toluene and formaldehyde. Bigger numbers, like 5-free or 10-free, add other ingredients to the omitted list, and brands choose which ones. There’s no legal standard for the count.

Two things to know:

• “3-free” doesn’t cover TPHP. A polish can be 3-free and still list triphenyl phosphate.
• DBP is already banned in EU cosmetics. It’s also on List I.

So “x-free” is a start. It tells you nothing about what the brand didn’t think to mention.

Label tips for choosing non-toxic nail polish

Nail polish ingredient lists are often tiny and sometimes only on the box. Look for these:

• Triphenyl phosphate or “TPHP.” Sometimes written “triphenyl phosphate.” If it’s listed, you know. If a brand says “TPHP-free,” that’s a more specific claim than “10-free.”
• Dibutyl phthalate (DBP). The one phthalate “3-free” covers.
• Fragrance or parfum. Less common in polish than in lotion, but the undisclosed blend is flagged the same way. See What “fragrance” on a label can hide.

Remember that “non-toxic” on a bottle is marketing. Like “clean,” it has no legal definition. We cover how that plays out in What is clean beauty?.

If you love polish

In the study, exposure came mostly through the skin, and a single application raised the metabolite. So the practical lever is the label: choose a polish that lists no triphenyl phosphate, and ask your salon whether you can bring your own.

If you’re pregnant or managing a condition, talk to your doctor; this isn’t medical advice.

For the rest of your makeup bag, see Non-toxic makeup. Formulas change; check the label on the bottle you buy.

How to read the evidence

It helps to be clear about what each piece of evidence can support.

• The Duke/EWG study measured TPHP in polish and a metabolite in urine after a manicure. It is a measurement of exposure, in a small set of products.
• The EU List I entry reflects a regulator-level judgment that TPHP is an endocrine disruptor. That is the reason it’s on our hormone list.
• Neither one tells you how much a given person’s manicure habit matters over time. A flag is a reason to look closer, not proof of harm.

The EU lists are updated at least twice a year; the last update was April 2026, and they’re worth checking when a name on a label is unfamiliar. Some entries do move: in April 2026, benzyl salicylate, benzophenone-4 and butylparaben came off List II after EU safety reviews (butylparaben stays on List I). TPHP and DBP are both on List I, which is the identified-at-EU-level group.

Why we say “we haven’t scanned it”

Nail polish is a different product from the lotions and lip products in our data, and we’d rather not extrapolate. The one thing our scans do show that carries over is that the label claim on the front and the ingredient list on the back are separate sources of information. In our 133 products, the most common flag by far was undisclosed fragrance, and you only find it by reading the list. Polish is the same: read the back, and if a brand only tells you how many things it leaves out, look for the specific names above before you buy.

Sources

• Mendelsohn et al., Environment International 2016 (Duke Scholars)
• EU endocrine disruptor lists (edlists.org)

Educational information, not medical advice. Formulas change, so check the label on the product you buy.