1.Sunscreen should only be used on sunny days. No, you need to use it all year round. It is key to remember that ultraviolet radiation penetrates through clouds (up to 90%), glass and water (at half a metre depth, we receive approximately 40% of UV radiation). Although the sun is harmful all year round, during spring and summer the amount of radiation we receive is even greater, due to the angle of incidence, which changes throughout the year and geographical location.

2. All types of solar radiation produce the same damage. No. UV-B rays are very energetic and are responsible for skin erythema. They penetrate the epidermis and cause skin tanning. Between 30% and 50% of UV-A rays reach deep into the dermis and are responsible for skin ageing and melanoma. UV-C rays are the most powerful, but are absorbed by the ozone layer, which is why we do not hear about them as often. Visible radiation (light effect) and infrared radiation (heat effect) penetrate into the hypodermis and cause skin photoageing.

3.An SPF 50 sunscreen protects twice as much as an SPF 25 sunscreen. This is not true, it is not a percentage that grows exponentially:

- SPF 2 blocks 50% of UV

- SPF 8 blocks 87.5% of UV

- SPF 16 blocks 93.6% of UV

- SPF 30 blocks 96,7% UV

- SPF 40 blocks 97.5% UV

- SPF 50 blocks 99% of UV

4. A sunscreen protects equally well against UV-B and UV-A. This is not true either. What is important when choosing a good sunscreen is that the ratio of UV-A protection should be at least one third of the UV-B protection it offers.

5. SPF is the number of minutes that the product protects from the sun. No, the SPF is a number that indicates the multiple of time the 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 performing in vivo tests on healthy volunteers.

6. Water-resistant is not the same as waterproof. Water-resistant means that the photoprotector has not lost its protective capacity (its SPF) after 40 minutes of swimming or continuous exposure to water. Waterproof means that the sunscreen acts for more than 80 minutes after contact with water.

7. Melanin is only good for tanning. This is a lie. Melanin is a natural defence 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