The importance of including an SPF in your skincare routine.

The sun emits electromagnetic waves that can be classified into different categories according to their wavelength: ultraviolet (UV) invisible to the eye (100 to 400 nm), visible light (400 to 700 nm) and infrared (700 nm to 1,000μm). Within the UV class, there are three subcategories: UVA (315-400 nm), UVB (280-315 nm) and UVC (100 nm-280 nm). UVC rays, the most powerful, are the only ones that do not reach us. This is because they are directly blocked by the ozone layer.

As for the other UV rays, 5% are UVB. They areresponsible for tanning, but also forsunburn, burns and the majority of skin cancers. They have the ability to penetrate the epidermis. With the epidermis, they activate the synthesis of melanin, the pigment that determines the colour of the skin. Meaning that tanning is simply our body’s defence mechanism for protecting us from the sun.

The intensity of UVB rays varies according to several parameters: the closer the season is to summer, the more we are exposed to them between 11 a.m. and 3 p.m., the closer we are to the Equator and at altitude, the more intense and dangerous the sun’s radiation will be.

The remaining 95% is UVA. These rays have the ability to penetrate deeper and reach the dermis. They will then cause significant damage by directly altering the components present, i.e. the collagen and elastin fibres, which are responsible for the firmness and elasticity of the skin. They can also cause genetic mutations within the DNA of cells and therefore eventually cause their death. In other words, UVA willlead to premature ageing of the skin, i.e. the appearance ofpigment spots, loss of elasticity, dehydration, and the appearance of fine lines and wrinkles.UVA rays are present at all times of the day, both in summer and winter and they can even pass through windows unlike UVB. This is why it is advisable to take certain precautions in order to protect yourself as well as possible from UV rays.

Our skin’s worst enemy is the sun. It accelerates skin ageing and contributes to the development of cancers. Prolonged and repeated exposure to the sun is always risky. This is why it is essential to protect yourself at all times by applying a product with asun protection factor (SPF), especially on the most exposed areas.

Even though the sun has somebeneficial effects on humans(it is an antidepressant, vitamin D synthesis, etc.), it also has formidable effects (photo-dermatosis, photo-ageing, photo-carcinogenesis) caused by UVA and UVB rays on the skin. Sun creamconstitue ainsi un moyen de photoprotection pour la peau. En effet, sa fonction est de protéger la peau des effets nuisibles du rayonnement solaire. Son efficacité repose sur les filtres ultraviolets qui peuvent contenir : les composés organiques/chimiques et les composés minéraux/physiques. Les filtres minéraux/physical filters act byreflecting and scattering UV radiation, while, alors que les filtres organiques/chemical filters act byabsorbing UV radiation.

When it comes to the sun, we are not all equal. Depending on our phototype, our reactions to sun exposure will be different. Typically, dark skin (phototype 6) will be less prone to sunburn, while very fair skin (phototype 1) will be more sensitive and vulnerable. Nevertheless, whatever your phototype, you should always apply sun protection. However, even if sunscreen plays an important role in protection strategies, it is important to take certain precautions in order to reduce the risks:

• Reduce exposure to the sun, especially during the hottest hours of the day, i.e. between 11 a.m. and 3 p.m.;

• Wear glasses, a hat and long clothes;

• Reapply sunscreen every 2 hours;

• Remember to apply sunscreen daily, even on cloudy days, to prevent skin ageing.