Plant-based nail polish: the claims and the chemistry behind them

Plant-based, bio-sourced and natural origin appear on more nail polish bottles every season. Manucurist prints 84 percent bio-sourced on its Green lacquer, Kure Bazaar claims up to 90 percent natural origin, and Gucci describes its Vernis à Ongles as plant-based. The words sound alike and mean different things.

A nail polish is a film former dissolved in solvents, softened by plasticisers and coloured by pigments. Each of those four groups can be traced to a plant, a mineral or a refinery. Knowing which is which turns a marketing line into a fact you can check on the ingredient list.

What does plant-based nail polish mean?

Plant-based nail polish is a lacquer in which part of the formula is made from plant biomass, most often the solvents and the cellulose used for the film former. Manucurist, which uses the term bio-sourced, defines a bio-sourced ingredient as one of biomass origin, meaning organic material from plants, animals, bacteria or fungi, and limits its own use of the word to plants because the brand is vegan (Manucurist).

Bio-sourced and natural origin are not the same claim. Manucurist puts it in one sentence: all bio-sourced ingredients are of natural origin, but not all ingredients of natural origin are bio-sourced. A mineral pigment such as lapis lazuli (CI 77007) is natural, because it is dug out of the ground, but it is not bio-sourced, because minerals are not biomass (Manucurist).

Organic is a third, separate claim. Manucurist states that a bio-sourced nail polish is not an organic nail polish, because solvents made by fermenting a crop do not obtain organic certification (Clever Beauty).

Which nail polish ingredients can come from plants?

The solvents are the largest part of a bottle and the easiest to source from crops. Butyl acetate and ethyl acetate are made by fermenting sugars from cassava, corn, sugar cane, cotton or potato into alcohol and acid, then combining the two (Clever Beauty). Manucurist names cassava as the source of the butyl acetate in its Green lacquer and Green Flash gel (Manucurist).

The film former is the second candidate. Nitrocellulose is made by combining cellulose with nitric acid and other compounds (NailKnowledge), and that cellulose comes from cotton linters or wood pulp. Kure Bazaar describes its lacquer as based on wood pulp, wheat, cotton, potatoes and corn, which covers both the film former and the solvents (Glasshouse Salon).

Plasticisers can be plant-derived too. Citrate esters are built from citric acid, which is produced by fermentation, and they replaced the phthalate DBP that the EU banned in cosmetics in 2004 (Label Lookout).

What stays synthetic in a plant-based nail polish?

Colour stays synthetic. Red, pink and violet pigments in polish are synthetic organic lakes or iron oxides, and the shimmer in a pearl or multichrome shade is mica or borosilicate coated with titanium dioxide or iron oxide. These are permitted colourants under Annex IV of the EU Cosmetics Regulation, and they are counted as mineral or synthetic, never as plant-based (Clever Beauty).

Adhesion resins stay synthetic. The resin that helps nitrocellulose grip the nail plate is a synthetic polymer in nearly every formula, and it is one reason the natural-origin number stops short of 100 percent.

The chemistry steps stay synthetic even when the raw material is a crop. Fermented alcohol becomes butyl acetate only after a reaction with acetic acid, and cellulose becomes a film former only after nitration. A plant-based polish is a plant-fed chemistry, not a plant extract.

How is the natural-origin percentage on the bottle calculated?

Most brands calculate the percentage using ISO 16128, an international standard that gives guidelines and formulas for the natural content of cosmetic ingredients and products. The standard defines a natural ingredient as one taken from plants, minerals or microorganisms with only physical processing or fermentation, and a derived natural ingredient as one from a natural source that has been chemically modified while keeping a significant part of its natural structure (Sophim).

The natural origin index adds both groups together. Fermented butyl acetate and cotton-derived nitrocellulose can both count as derived natural, which is how a solvent lacquer reaches a number in the eighties or nineties. Water counts as natural under the standard, which matters for water-based polish (Sophim).

ISO 16128 is a calculation framework, not a certification. No body inspects the bottle and awards a logo, and the standard does not set a threshold above which a product may be called natural (Sophim). The number is a self-declaration, and a brand that wants it checked names the method next to it.

Does plant-based nail polish perform differently?

Bio-sourced butyl acetate is the same molecule as petrochemical butyl acetate. It evaporates at the same rate, has the same flammability warning and gives the same smell. A plant-based solvent lacquer dries in the same 3 to 5 minutes to touch as any regular polish and takes hours to harden fully (Nagelstudios.nl). Wear and gloss depend on the film former, resin and plasticiser balance, not on where the carbon atoms were grown.

The ingredient list cannot show origin either. The international nomenclature of cosmetic ingredients (INCI) names a substance by what it is, so butyl acetate reads as butyl acetate whether it came from cassava or from crude oil.

The one practical difference is the free-from list that usually accompanies the claim. Plant-based brands are typically 10-free or 12-free. In Europe that overlaps with the law, because DBP, formaldehyde and toluene above set limits are already prohibited or restricted under Regulation (EC) 1223/2009 (Label Lookout).

How to judge a plant-based nail polish claim

You will need: the ingredient list on the box or the brand website, the exact wording of the claim, and five minutes.

1. Read the wording. Bio-sourced or plant-based means biomass. Natural origin includes minerals and water. Organic requires a certifier's logo, which no solvent lacquer has.
2. Find the percentage and the method. A number without a standard next to it (ISO 16128 or an equivalent) is a slogan. A number with the standard is a calculation you can question.
3. Check which ingredients are named as plant-derived. Solvents from cassava, corn or sugar cane and cellulose from cotton or wood pulp are plausible. Pigments described as plant-based are not, apart from rare exceptions.
4. Look at what the free-from list excludes. If it lists only ingredients the EU already bans, the list adds nothing in Europe. If it includes TPHP and camphor, it goes beyond the law (Label Lookout).
5. Check the claim against EU rules. Cosmetic claims in the EU must follow the common criteria of Regulation (EU) No 655/2013, which require them to be truthful, supported by evidence and not misleading (EUR-Lex). A claim that suggests the whole polish is a plant product fails that test.
6. Weigh it against what you need. Fumes, drying and wear are formula questions that a plant-based label does not answer.

Is plant-based nail polish safer for nails or health?

Safety in the EU is decided by Regulation (EC) 1223/2009, which applies to every cosmetic regardless of origin. A plant-based lacquer and a petrochemical one pass the same safety assessment and are notified through the same cosmetic products notification portal (CPNP).

For the nail plate, the film is what matters. Solvents dry the surrounding skin whichever crop they came from, so the routine is the same: cuticle oil daily, thin coats and short contact with remover. If nails split or change colour without an obvious cause, see a GP or dermatologist.

The plant-based claim is an environmental and sourcing statement. Bio-sourced solvents replace petrochemical feedstock with a renewable crop, which Manucurist describes as a greener production route with a lower environmental impact (Manucurist). That is a sound reason to choose one. Expecting it to change how the polish behaves on the nail is not.