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Solvents, resins, plasticizers, pigments, photo-initiators... Behind a bottle of varnish hides a combination of chemical elements that vary according to the type of varnish, whether it is classic, bio-sourced, water-based or photopolymerized. In recent years, several substances traditionally used in the manufacture of varnishes have been banned in Europe for their effects on human health. Others remain allowed but are under surveillance because they may be sensitized or irritating. So how do we know if a varnish is safe and healthy? We'll give you the keys to avoid bad surprises.

In short: which nail polish is the healthier?

The healthier nail polish is a varnish whose formula is free of CMR, endocrine disruptors or monomers, who dry in the open air and withdraws without sanding or acetone. Bio-based varnishes most often meet these criteria while offering a close look to the classic formulas.

The semi-permanent varnish Demand more vigilance: methacrylate monomers (HEMA and di-HEMA banned in Europe in cosmetics for sale to individuals) are among the most reported contact allergens and its removal weakens the nail.

To choose your varnish, the list printed on the packaging remains the most reliable tool, much more than a mention clean or x-free The definition of the mark varies from one brand to another.

Is nail polish harmful to health?

No, nail polish is not dangerous to health when it is used on a point basis and purchased in a controlled circuit. However, some formulas contain allergenic, irritating or suspected endocrine disrupting substances, the impact of which varies depending on the type of varnish and the frequency of application.

The good news is that in Europe, the cosmetic composition sold to private individuals is strictly framed. The Regulation (EC) No 1223/2009 excludes any ingredient that poses a risk to human health and formally prohibits the use of substances classified as carcinogenic, mutagenic or toxic to reproduction (CMR). That's reassuring!

However, the risk is not zero, particularly if products purchased outside the EU are used, and exposure is through two means:  

• Skin In case of overflow, the varnish is in contact with the skin and its molecules can cross the skin barrier. Some people may then develop contact allergy or irritation on their fingers, with the risk that it will spread to other parts of the body by contact. More generally, once absorbed, these molecules circulate in the body and can disrupt its metabolism.
• The respiratory tract Volatile solvents can be inhaled during laying and drying and cause asthma, headache or breathing difficulties in sensitive people.

What substances make varnish harmful?

The controversial ingredients are divided into three families: endocrine disruptors and CMR substances, contact allergens and irritants. They all perform a precise technical function, film flexibility, shine, adhesion or color stability, which explains their historical presence in the formulas.

Endocrine disruptors and CMR substances

Both families combine ingredients with the most serious long-term effects, in terms of hormonal functioning, cancer risks, genetic disorders or reproductive problems.

Dibutyl phthalate (Dibutyl Phthalate or DBP) long served as a plasticizer: it softens the varnish film and prevents it from scaping. It is classified as toxic to reproduction and is now banned in cosmetics sold in the European Union. Many manufacturers have replaced it with the triphenyl phosphate (Triphenyl Phosphate or TPHP). This plasticizer is in turn suspected of disrupting the endocrine system, and it will be prohibited from 2027.

Benzophenones (Benzophenone-1, Benzophenone-3) are UV filters that prevent the colour from discoloring in light. They are also suspected of acting as endocrine disruptors.

The OPT (Trimethylbenzoyl Diphenylphosphine Oxide) is a photoinitiator. It triggers the hardening of semi-permanent varnishes under the lamp, and it is classified as toxic for reproduction. It is banned in cosmetics since September 2025 in Europe. A bottle purchased before this date may still contain one: check the INCI list of semi-permanent varnishes you already have at your home.

Formaldehyde (Formaldehyde) was used as a hardener to strengthen nails. He is classified as a carcinogen and also a contact allergen. If no longer used as such, its derivatives always appear in varnish formulae.

Contact allergens

A contact allergen usually does not trigger a reaction from the first application. Skin becomes more sensitive as exposures progress, then react to each new contact. Possible reactions are redness, itching or eczema around the nail. They can also appear on the eyelids, face or neck, areas you touch with your fingers.

The resin tosylamide/formaldehyde (Tosylamide/Formaldehyde Resin) is a filmogenic resin that brings shine and adhesion. It's one of the historical allergens of varnish.

Colophane (Colophonium, Rosin) is a resin from pine sap. It improves the nail-like nail-catching of the varnish. It is a recognized contact allergen, which reminds us that an ingredient of natural origin is not necessarily risk-free.

Methacrylate monomers (HEMA, Di-HEMA Trimethylhexyl Dicarbamate) are at the base of semi-permanent varnishes. They polymerize under UV or LED lamps. Before hardening, these liquid molecules easily penetrate the skin. The risk increases when the product overflows on cuticles or when polymerization is incomplete, due to an inappropriate lamp or too short exposure time. These are the most common allergens in nail laying today. Once installed, the allergy is durable. In Europe, nail products containing these substances are prohibited for sale to individuals since 2021 and their use is restricted to professionals under conditions.

Irritant substances

Toluene (Toluene) and xylene (Xylene) keep the liquid varnish in the vial. They then evaporate to let the film dry, and it is these vapors that are the problem. In a poorly ventilated room, they can irritate the airways and eyes, causing headaches and dizziness. Repeated exposures are the most at risk, especially for professional in-school workers. Toluene is also suspected of being toxic to reproduction.

The Camphor (Camphor) is a plasticizer rather than a solvent, but it has similar irritant effects. It is also toxic when swallowed: keep the vials that contain them out of the reach of children.

How do I know if a varnish is healthy?

The International Nomenclature of Cosmetic Ingredients (INCI) is compulsory on all cosmetics sold in the EU. The ingredients appear in descending order of concentration, then in free order below 1%. The names are written in English or Latin, which allows them to be identified regardless of the language of the package.

Here are the substances to be found in the INCI lists of your beauty products that are to be avoided:

The entries 5-free, 9-free or 16-free no regulatory definition is observed: each brand sets its own list of exclusions. The figure is less important than the substances actually excluded, to be compared with the table above.

The level of bio-sourced ingredients indicates the share of vegetable matter such as sugar cane or cassava. This is neither a biological certification nor a guarantee of skin tolerance, but colophan is the standard example.

What kind of varnish is the healthier?

For regular use, bio-based varnish without controversial substances offers the best balance between health, nail hold and nail respect. The varnish in water contains the least solvent but lasts less time, while semi-permanent cumulates the points of vigilance. Find out at a glance the advantages and the points of vigilance specific to each type of varnish:

The water varnish is suitable for children and people sensitive to solvent odours. Classic and bio-sourced LED varnishes are for those who want a result close to classic or semi-permanent varnishes with premium, a formula lightened in controversial ingredients.

Is semi-permanent varnish the least healthy?

Yes, traditional semi-permanent varnishes are the most hazardous in current varnishes, for four reasons related to their chemical composition and use:

• Methacrylates, as we have seen, are powerful allergens, especially when the product touches the skin or polymerizes badly under the lamp. Awareness is definitive and can complicate dental or orthopaedic care using acrylic materials. Fortunately, since 2021 semi-permanent varnishes with HEMA and DI-HEMA molecules have been banned from sale to individuals in Europe and their professional use is strictly supervised.
• The OPT, a historical photo-initiator long used in semi-permanent formulas, is classified as toxic to reproduction. The Regulation (EU) 2025/877 prohibited since 1 September 2025, without delay in the disposal of stocks. However, bottles are still circulating on retail platforms, which means that it is important to buy from reliable circuits.
• Catalysis lamps, including LED, emits UVA. Researchers have observed laboratory damage to human cells exposed very regularly, without a risk of cancer being demonstrated in users. A sunscreen or gloves without fingers limit this exposure.
• DepositFinally, usually involves a ten minute soak in acetone and a surface limage. These two gestures dehydrate and thinn the nail plate, especially when poses are continuously chained.

What varnish does the nails damage the least?

A varnish that dry in the open air and who is withdraw with a soft solvent without acetone, is the one that will damage your nails the least. The damage comes more from repeated poses and removal than from the varnish itself. The more conventional or semi-permanent varnishes are put together, the more nails are exposed to theacetone. This product dissolves the lipids that ensure the cohesion of the keratin layers. The result: the nail becomes dry, brittle and split. Surface sanding before or after a semi-permanent period removes a fine thickness at each installation. It is then essential to feed the nail in depth in order to stimulate keratin production and allow the plate to be renewed.

👉 The solution? The Commission has already taken a number of steps to improve the quality of the information. bio-based varnishes which avoids these inconveniences while offering comparable performance to classic and semi-permanent varnishes in terms of hold and shine.

A beautiful and more nail-friendly varnish: the Manucurist approach

At Manucurist we formulate our varnishes for cprofessionally rendered oncile and composition respectful of consumer health. To do this, we are making sure that at-risk molecules are banned from our products even if they are not yet prohibited by regulation. And we replace petrochemical ingredients with mild alternatives, extracted from biomass, as much as possible.

The nail polish Green™ contain up to 83% of ingredients of plant origin, derived in particular from cassava, maize, sugar cane or cotton. Their formula is free of DBP, toluene, formaldehyde, formaldehyde resin, camphor, HPPT, xylene, parabens and animal ingredients. These varnishes are easy to put, dry in the open air, without UV or LED lamps, and last up to seven days. Finally, it is remove in a minute with a soft solvent without acetone. Ideal for a simple and fast manicure that preserves nails.

For those who seek the long hold of the semi-permanent without the risks that go with it, the range Green Flash™ offers a varnish composed of 84% bio-sourced ingredients, guaranteed without HEMA, TPO and other harmful substances. It dries under a LED lamp with a power not exceeding 36W, with a catalysis time of 5 to 10 minutes max per manicure, thus limiting UVA exposure. Green Flash™ se remove without acetone and without sanding, with a suitable soft solvent, which avoids the alteration of the plate and allows to enjoy a beautiful manicure up to 12 days.

We recall that an allergic reaction is still possible with plant ingredients. If you have an allergy history, we strongly recommend that you compare the INCI list with the results of your allergy tests.