There’s a lot of talk about sun exposure, sun products and the effects of the sun on the skin, but… what’s true and what’s false? Can we trust everything we read or are told? Rocío Franco, pharmacist specializing in dermocosmetics for Gisèle Denis, reveals the main myths that exist around sun exposure (and that you have always believed). Take note!
Only use sunscreen on sunny days. No, you have to use them all year round. It is important to remember that ultraviolet radiation penetrates clouds (up to 90%), glass and water (at a depth of half a meter we receive about 40% of UV radiation). While the sun is harmful all year round, the amount of radiation we receive in the spring and summer is even greater because of the angle of view, which changes throughout the year, and the geographic location.
All types of solar radiation cause the same damage. No. UV-B rays are very energetic and responsible for skin erythema. They penetrate to the epidermal level and cause tanning of the skin. Between 30% and 50% of UV-A rays reach deep levels of the dermis and are responsible for skin aging and melanoma. UV-C rays are the most powerful, but they are absorbed by the ozone layer, which is why we don’t hear about them very often. Visible radiation (light effect) and infrared radiation (heat effect) penetrate into the hypodermis and cause photoaging of the skin.
A sunscreen with SPF 50 protects twice as much as a sunscreen with SPF 25. This is not true, it is not a percentage that grows exponentially:
- – SPF 2 blocks 50% UV
- – SPF 8 blocks 87.5% of UV
- – SPF 16 blocks 93.6% of UV
- – SPF 30 blocks 96.7% of UV
- – SPF 40 blocks 97.5% of UV
- – SPF 50 blocks 99% of UV
A sunscreen protects against UV-B the same as against UV-A. Nor is it true. The most important thing when choosing a good sunscreen is that its UV-A protection ratio should be at least one-third of the UV-B protection it provides.
The SPF is the number of minutes the product protects from the sun. No, the SPF is a number that indicates how many times a protected skin can be exposed to achieve the same erythematous effect that would be obtained if no protection had been applied. It is obtained by conducting in vivo tests on healthy volunteers.
Water repellent is not the same as waterproof. Water resistant means that the photo protector has not lost its protective capacity (its SPF) after 40 minutes of swimming or continuous stay in the water. Waterproof means that the sunscreen works for more than 80 minutes after contact with water.
Melanin only serves to tan. Lie. Melanin is a natural defense mechanism of our skin against solar radiation. There are two types, Eumelanin (dark brown), which absorbs UV rays and allows the skin to protect itself from the sun; and pheomelanin (yellow-orange), which is not photoprotective, but photoaggressive due to the production of free radicals.
Source: Marie Claire
