Understanding permanent nail varnish.

Permanent nail varnish is a long-lasting manicure technique that provides a glossy and uniform finish for several weeks. Unlike traditional nail varnishes, it is not applied directly onto the nail but relies on the use of an acrylic gel, commonly referred to as "UV gel" or "building gel". This gel is moulded onto the nail before being hardened under a UV or LED lamp, through a process of photopolymerisation that solidifies the material and makes it particularly resistant. Permanent nail varnish also allows for the modification of the nail's shape or length, through the addition of extensions.

The permanent nail varnish is primarily aimed at individuals who desire long-lasting, impeccable nails with a meticulous finish, often stronger than that provided by semi-permanent varnishes. However, due to its technical nature, the application of permanent nail varnish should be carried out in a salon, by a professional trained in the use of gels and UV lamps.

The distinguishing feature of permanent nail varnish is its remarkable durability, lasting up to a month.

The application of a permanent varnish is a meticulous process. Firstly, the beautician begins by cleaning the nails, removing any traces of varnish, dirt or oil present on their surface. Once this step is completed, the cuticles are pushed back. A base layer is then applied to the nail, followed by a session under a UV or LED lamp to harden this initial layer. This hardening is essential to ensure the gel adheres to the nail surface. After this, one or more layers of coloured gel are applied, each hardened under the lamp. Depending on the desired colour and intensity, several applications may be necessary. Once the permanent varnish is hardened, a clear varnish, or top coat, is applied to form a finishing layer and seal the varnish.

The application of a permanent varnish typically takes between 45 minutes to 1 hour.

When it comes to removing a permanent nail varnish, it also requires precautions and special care. Indeed, unlike a traditional varnish, no remover will be able to tackle a permanent varnish. To remove it, it is necessary to gently scrape the nail with a wooden stick. To facilitate the removal, it is possible to wrap the nails in cotton pads soaked in acetone for about fifteen minutes beforehand. If this is not enough to remove the permanent varnish, it helps to soften the gel and make its removal easier. After removal, a restorative and hydrating treatment, such as an oil or balm, is applied to restore the nails' water balance.

It is strongly advised against attempting to remove permanent nail varnish by oneself as improper removal could damage the nails.

Just like semi-permanent nail varnishes, permanent nail varnishes raise questions about their effects on nail health. Indeed, while they provide a long-lasting and resilient manicure, they can weaken the nails. The main risk associated with regular use of permanent nail varnishes lies in their occlusive effect. By covering the nails with a thick layer of gel, these products can increase their moisture and make them soft. In fact, when the keratin of the nail absorbs too much water, it swells, which causes the layers that make up the nail to separate and potentially split. The successive application and removal of permanent nail varnishes can also weaken the nails, especially if they are not done properly.

To minimise the negative effects of permanent nail varnish on the nails, it is important to observe several weeks of rest between each manicure.

Furthermore, permanent nail varnishes, like semi-permanent ones, contain several chemical substances which, while effective in ensuring long-lasting wear, can pose health risks, particularly when used regularly. Notably, these include phthalates, toluene, and formaldehyde, chemical compounds that can be irritating to the skin and respiratory tract and cause allergic reactions.

Although their names are similar and they share several characteristics, such as long-lasting wear and polymerisation under UV or LED light, permanent varnish and the semi-permanent varnish have notable differences, both in their formulation and in their application method, their finish or their durability. These differences are summarised in the table below.

• DINANI N. & al. Nail cosmetics: a dermatological perspective. Clinical and Experimental Dermatology (2019).

• PAIVA LUZ P. & al. Nail Polishes: A Review on Composition, Presence of Toxic Components, and Inadequate Labeling. Dermatology, Research and Practice (2025).