Understanding permanent nail polish.

Permanent nail polish is a long-lasting manicure technique that provides a glossy and even finish for several weeks. Unlike traditional nail polishes, 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 shaped onto the nail before being hardened under a UV or LED lamp, through a photopolymerization process that solidifies the material and makes it particularly resistant. Permanent nail polish also allows for the modification of the nail's shape or length, through the addition of extensions.

The permanent nail polish is primarily for those who desire long-lasting, impeccable nails with a neat finish, often stronger than that provided by semi-permanent polishes. However, due to its technical nature, the application of permanent nail polish should be done in a salon, by a professional trained in the use of gels and UV lamps.

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

The application of a permanent nail polish is a meticulous process. First, the aesthetician begins by cleaning the nails, removing any traces of polish, dirt, or oil present on their surface. Once this step is completed, the cuticles are pushed back. A base coat 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's adherence to the nail surface. After this, one or more layers of colored gel are applied, each hardened under the lamp. Depending on the desired color and intensity, several applications may be necessary. Once the permanent polish is hardened, a clear polish, or top coat, is applied to form a finishing layer and seal the polish.

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

When it comes to removing permanent nail polish, it also requires precautions and special care. Indeed, unlike traditional nail polish, no remover can effectively remove permanent nail polish. 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 soaked in acetone for about fifteen minutes beforehand. If this is not enough to remove the permanent polish, 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' hydration balance.

It is strongly advised not to attempt to remove permanent nail polish by oneself as improper removal could damage the nails.

Just like semi-permanent nail polishes, permanent nail polishes raise questions about their effects on nail health. Indeed, while they provide a long-lasting and resistant manicure, they can weaken the nails. The main risk associated with regular use of permanent nail polishes 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 polishes can also weaken the nails, especially if they are not done properly.

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

Furthermore, permanent nail polishes, like semi-permanent ones, contain several chemical substances that, while effective in ensuring long-lasting wear, may 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 polymerization under UV or LED light, permanent nail polish and semi-permanent nail polish have notable differences, both in their formulation and in their application method, finish, and durability. These differences are summarized 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).