What is the benefit of applying an after-sun lotion?

While the sun is a source of benefits for the skin, it is crucial not to overlook the dangers posed by long and frequent exposures. Indeed, these can have several harmful effects on the structure and function of the skin and can significantly alter the skin barrier. Formulated to soothe skin weakened by the sun and available in various forms, after-sun products have multiple virtues:

• After-sun products help to rehydrate the skin.

  It is normal for the dermis to lose between 300 and 400 mL of water per day, passing through diffusion across the epidermis and then evaporating once it reaches the surface of the stratum corneum. This physiological process is essential: it promotes hydration of the skin's superficial layers and allows for the upward movement of nutrients from the dermis to the epidermis, a crucial element considering the latter is not vascularized. However, during sun exposure, insensible water losses increase and the water balance is disrupted.

  To restore it, it is beneficial to apply a moisturizing treatment with a fresh texture, such as an after-sun lotion. This product notably helps to restore the hydrolipidic film present on the skin's surface, which plays a protective role. The primary function of the after-sun lotion is thus to combat skin dehydration and prevent the skin from peeling.

• After-sun products help to re-lipidize the epidermis.

  During exposure to UV radiation, the entire skin barrier becomes destabilized and a loss of lipid function can be observed. These compounds of the intercellular cement play a crucial role in skin protection and in preventing dehydration. By promoting the production of free radicals in the skin, UV rays disrupt the horny layer. Indeed, free radicals react with lipids in a process known as lipid peroxidation. This reaction generates inflammatory by-products such as the superoxide anion, which can damage skin tissues and DNA.

  Often rich in lipid-replenishing active ingredients such as ceramides or vegetable oils, after-sun products help to nourish the epidermis and restore the protective function of the skin barrier. They thus assist in maintaining hydration and contribute to the repair of cells damaged by UV rays.

• After-sun products reduce inflammation.

  UV rays tend to stimulate skin inflammation through several mechanisms, including by increasing the levels of oxidative stress in cells. Indeed, the free radicals they generate can activate certain nuclear factors like the AP-1 transcription factor, which is involved in the release of cytokines, playing a role at different levels of inflammation and promoting redness and swelling. They particularly promote the synthesis of adhesion molecules, immunoglobulins that play an important role in controlling the circulation of leukocytes.

  After-sun products are soothing solutions, formulated with anti-inflammatory ingredients such as calendula, aloe vera, or panthenol. By combating inflammation, these various active ingredients help to soothe skin weakened by sun exposure while minimizing the sunburn. This effect is also enhanced by the cool texture that most after-sun products possess.

• After-sun products extend the tan.

  One of the reasons why sun exposure is so cherished is the beautiful tan it allows one to achieve. To maintain it as long as possible, the application of an after-sun product can prove to be an ally. Indeed, by enhancing the skin's hydration, this care prevents it from peeling, a factor that accelerates the loss of tan.