How to choose your sun protection when you have brown spots?

Brown spots are caused and/or exacerbated by a phenomenon known as oxidative stress. As a reminder, this phenomenon results from the overproduction of pro-oxidant species in cells, and/or the reduction of cellular antioxidant capacity, and can damage DNA, cell membrane lipids, and proteins, leading to mutagenesis or cell death. Reactive oxygen species (ROS) are produced by mitochondria and peroxysomes during normal cellular metabolic processes. However, ROS production can be heightened under pathological conditions, such as inflammation and cancer, as well as when exposed to exogenous factors, like ultraviolet (UV) rays.

The skin is the largest organ interfacing with the environment, and a major source of ROS (Reactive Oxygen Species) that are induced by sun exposure. Epidermal melanocytes are particularly vulnerable to excessive ROS production due to their specialized function: the synthesis of melanin, which is stimulated by sun exposure during the tanning process. When melanocytes are disrupted, they produce excess and disorganized melanin, leading to brown spots known as solar lentigines. Be aware, the use of certain photosensitizing medications can promote these types of brown spots. For your information, there are other types of hyperpigmentation such as melasma caused by hormonal fluctuations and exacerbated by exposure to UV rays.

Solar lentigines primarily appear on the parts of the body most frequently exposed (back of the hands, shoulders, face). Moreover, lentigo can also be caused by the aging of the skin. With age, the skin fails to fully protect itself from external aggressions and deteriorates. A dysfunction of melanocytes is observed, associated with the exhaustion of their pigmentary potential at the level of hair follicles. This phenomenon is also correlated with the consequences of repeated attacks of reactive oxygen species (or free radicals) on the nuclei of melanocytes and mitochondria. When this happens, the skin becomes vulnerable to UV rays, responsible for pigmented spots then called "age spots".

To prevent this, at any age, it is therefore essential to apply a sunscreen suitable for your skin tone before sun exposure.

Some active substances have the ability to stabilize free radicals, thereby making them much less harmful to the skin and preventing the onset of various deteriorations such as dark spots, but also wrinkles, skin sagging, and so on...

Among these preventive ingredients for hyperpigmentation, we find vitamin C, ferulic acid, resveratrol , and even limonium extract, etc... which neutralize free radicals. Certain vegetable oils also have the ability to trap free radicals due to their composition. This includes karanja oil, particularly rich in furanoflavonoids (karanjin and pongamol) or even plum vegetable oil.

At Typology, we offer two facial sunscreens with two different Sun Protection Factors (SPF): one with SPF 30 and another with SPF 50. Both are enriched with antioxidant agents such as karanja oil for the SPF 30 and limonium extract for the SPF 50.

Furthermore, the body is not immune to the appearance of sun spots, quite the contrary, so it's important to protect yourself well. We also offer two levels of sun protection for the body, SPF 30 and 50.

Note: Even though sunscreen can protect the skin from hyperpigmentation spots, we recommend avoiding sun exposure between 11 a.m. and 3 p.m.

• DENAT L. Melanocytes as instigators and victims of oxidative stress. Journal of Investigative Dermatology (2014).