Fake news reaches sunscreen: "The real danger is stopping using it."

BarcelonaLike every summer, the beaches are filled with tourists with reddened skin, and it is also becoming a tradition for social networks to be filled with pseudo-doctors. who encourage people not to use sunscreen. Among them is Marcos Llorente, the well-known Atlético de Madrid footballer, who has stated on several occasions that he sunbathes for more than four hours at a time without applying any protection, and that "the sun is not the cause of skin cancer." He has also asserted that his family also does not use sunscreen, and posted a photo of his father on Instagram, topless, claiming that he hasn't used it his entire life (60 years), and asking his followers: "Where are your spots on your skin?"

These denialist claims have hundreds of followers on social media, but also within the medical field, where some claim that "you don't need to wear sunscreen if you eat a good diet, without vegetable oils, which prevents sun damage." This is also supported, for example, by Dr. Zac Bush, who has 800,000 followers on Instagram although he is not a dermatologist or oncologist. But what is reality and myth regarding the use of sunscreen?

The best sun protection for our skin is to avoid exposing it, but when it's impossible to avoid it, "clothing becomes the best sunscreen there is," says Dr. Jordi Mollet, a dermatologist at Vall d'Hebron Hospital. However, during the summer months, it's not always feasible to wear long-sleeved shirts or pants that completely cover the legs. In these cases, sunscreen becomes our best ally for protecting our skin. "The danger is stopping using it," he says. According to studies conducted by the Queensland Institute of Medical Research in Australia, the correct use of sunscreen can reduce the risk of cancer by between 50% and 70%.

It's all due to the sun's ultraviolet (UV) rays, which are responsible for premature skin aging and the appearance of wrinkles, as they degrade collagen and elastin. Furthermore, UV rays can damage the DNA of skin cells and cause mutations that can lead to skin cancers, a correlation confirmed by the World Health Organization (WHO). One in three cases of cancer worldwide is skin cancer, and the main cause is UV rays. In fact, 95% of skin cancers are linked to prolonged sun exposure, especially in fair-skinned people.

Now, these risks don't negate the benefits of moderate sun exposure, such as higher levels of vitamin D and serotonin and a reduced risk of type 2 diabetes or some types of cancer. A correlation has also been found between spending time outdoors and certain mental health benefits, as well as the regulation of sleep cycles, especially during the winter months. But moderate exposure is a far cry from getting burned from spending hours with a large part of your body exposed, as many sunbathers do in the summer.

Vitamin D

Sunscreens contain filters that absorb UV rays, reducing the amount of ultraviolet radiation that reaches the skin and, therefore, also vitamin D synthesis, which can decrease by up to 98%. However, according to a 2017 study by the Polytechnic University of Valencia, in spring and summer, exposing a quarter of your body—hands, face, neck, and arms—to the sun for between 8 and 10 minutes at midday is enough to produce the recommended daily amount of vitamin D.

50—the most recommended—can generate a false sense of security. The important thing, warns Dr. Mollet, is "not to overuse the sun under any circumstances." Furthermore, activities such as swimming or rubbing yourself with a towel reduce the effectiveness of the sunscreen, and the simple fact of having to reapply it already indicates that we have been exposed to the sun for too long.

Sunscreen: a harmful product?

Another argument from deniers is that the compounds in these products are harmful to the skin. The evidence they point to is a 2019 study by the U.S. Food and Drug Administration (FDA), which found that some of these organic compounds could penetrate the skin and enter the bloodstream. Following these results, see how Dr. Tro Kalayjian, who runs a weight-loss clinic in the U.S., published the study in X, adding: "Watch what you put on yourself and your children."

But the study analyzed the sunscreen under maximum use conditions, which meant applying a lot of sunburn. Under real-life conditions, people applied about one-tenth of the amount used in the study. That alone would put three of the four ingredients below the FDA's recommended threshold, according to post-study reviews by experts.