Health. SPF, makeup, allergies... what you need to know about sunscreen

Summer begins Saturday with bright sunshine and the first wave of heatwaves . Many of you will be taking advantage of the opportunity to sunbathe and tan. The prevention campaign launched Monday by the French Cancer League, calling for people to protect their skin from the sun, is therefore timely.

Knowing that 80% of skin cancers are due to overexposure to ultraviolet (UV) rays emitted by the sun, the League reminds us that "grilling in the sun causes 80,000 skin cancers and 2,000 deaths per year." It therefore launched a humorous advertising spot entitled "We are not sausages" to get the message across. Because the number of melanomas (the most aggressive skin cancers) has quadrupled since 1990, while "40% of cancers are preventable by changing behavior," it specifies. This increase is partly explained by an increase in risky practices, such as artificial tanning booths, which do not protect the skin and prepare it for UV rays, and more frequent sun exposure.

To protect your skin—and your health—it's essential to avoid sun exposure between 12 p.m. and 4 p.m., and above all, to protect your skin with sunscreen. SPF, factor, protection time... how do you choose the right protection for your skin?

SPF, Sun Protection Factor (or Sun Protector Factor in English) "is a sun protection scale displayed on tubes, indicating the level of protection against UVB rays, which are the cause of sunburn and burns," explains Erwan Poivet, scientific advisor for Febea (Federation of Beauty Companies). An SPF of 50 "does not guarantee 50 minutes or 50 hours of protection, it is not linked to that, it is the sun filters applied in the cream that will absorb part of the UV energy. The higher the SPF index, the better the protection, but in any case it will be necessary to reapply it every two hours," specifies the scientific advisor. If you have fair skin, it is therefore recommended to go for a high SPF (50 or 50+).

To be complete, a good sunscreen must also protect against UVA rays, "which, unlike UVB rays, are able to pass through glass." "They penetrate deeper into the skin, down to the dermis, whereas UVB rays stop before (the epidermis) and are responsible for skin aging, such as the appearance of wrinkles," adds Erwan Poivet.

Sunscreen shouldn't just be applied during a day at the beach, but also if you're spending the day in the sun, even in the city, while jogging, or in your garden. This advice is especially true for outdoor workers (farmers, construction workers, waiters), who don't have a chosen exposure, but rather an exposure imposed by their job. They don't always have the reflex to protect themselves from the effects of the sun "and therefore have a higher rate of developing skin cancer than the rest of the population," notes Erwan Poivet.

Another important point: the quality of the cream application. It must be spread evenly to be effective . A cream with water resistance can be useful if you are going to swim and will guarantee its ability not to mix with the water. However, the two-hour renewal cycle must always be applied.

For sensitive and sun-allergic skin, it is essential to use a suitable sunscreen such as total sunscreen (UVA + UVB) with SPF 50+. In addition, your doctor may prescribe corticosteroid creams or antihistamines.

If you're a regular makeup wearer, many creams and foundations list an SPF in their ingredients. However, it's often low and only provides secondary UV protection. It can protect skin in winter when the sun isn't very strong, but it won't be effective enough in spring/summer. Additionally, while sunscreen should be reapplied every two hours, this isn't the case with foundation.

Finally, if you're hesitant because of the price of a sunscreen, which can vary from simple to double, the protection depending on the index will be the same, since these products meet European standards. The important thing is therefore to choose the right SPF for your skin. "The price difference is mainly explained by the galenic, that is to say the texture of the cream: milky, spray, lotion, stick, etc.," adds Erwan Poivet. You no longer have any excuses for not slipping a tube of sunscreen into your suitcase and not burning like a sausage...