Nail polish lovers have seen brands like Chanel, Butter London, and Zoya advertising themselves as “three-free” or “five-free.” Sadly, that doesn’t mean you should expect complimentary bottles of lacquer — it means that these nail polishes were made without chemicals believed to be harmful. “Three-free” polishes are made without formaldehyde, toluene, and dibutyl phthalate (DBP), while “five-frees” cut out these chemicals as well as formaldehyde resin and camphor.

RGB five-free scarlet

All five of the above ingredients are often added to conventional formulas as hardeners, straighteners, or to preserve the appearance or shelf life of the polish,” explains Gina Carney, the founder of RGB Cosmetics, a five-free nail polish and nail care line. “At the same time, those ingredients have resulted in tests claiming they are harsh carcinogens that have been linked to impaired breathing, nausea, dizziness, headaches, or allergens.

Further complicating the matter is how the five ingredients are permitted in some products in the United States yet they’re straight-up banned in other countries. For example, formaldehyde (also a key ingredient in Brazilian blowouts) has been banned in EU nations. These chemicals are also reportedly tougher on people with allergies, which is why brands like Clinique have been working on special formulas for people with asthma and sensitive skin.

Kim D’Amato, the founder of “five-free” polish brand Priti NYC, uses the stricter European regulations on beauty products as her guiding force, even though her company is based in the U.S. “In Europe, cosmetics are not tested on animals,” she explains. “Unlike other companies, we have passed all the EU regulations and all the safety tests for the EU; therefore, we can have several retailers in Europe.

“Three-” and “five-free” polishes can be, but are not necessarily, vegan. “A nail product can be ‘five-free’ but not vegan,” Carney says, adding that her nail polishes have both certifications. “Vegan is essentially a buzzword for ‘cruelty-free.’ A cosmetic product labeled ‘vegan’ means that the product is has not been tested on animals [and doesn’t] contain any animal byproducts.” The Vegan Claws blog is a great resource for keeping track of vegan and animal-friendly polish brands.

Interestingly, “five-free” polishes aren’t the last word in nontoxic nail care: the 100% vegan brand Pacifica recently launched a line of seven-free polishes. Yup, seven. The extra two chemicals they’ve removed from the formula are parabens (a preservative) and xylene (a solvent/adhesive).

Just as people are asking questions about the ingredients in their food, beauty consumers want more info about what’s in their makeup and skincare products. For D’Amato, that transparency can only be a good thing. “Terms such as ‘five-free’ are a marketing way to promote the fact the products do not have chemicals in them and also to educate consumers of product formulations,” she explained.

Does this mean we should expect nine, 11, and 13-free polishes in the future? Hard to say. But at this rate, polish brands might be better off explaining what’s in the products rather than what isn’t.