Which sun protection myths are true?
Whoever lies in the sun should make sure to properly apply sunscreen beforehand. However, there are various claims and tips circulating about sunscreen protection - whether from sunscreens in tubes or through specific diets. Does pre-tanning in a tanning bed really help and does a day cream with an LSF suffice? Fact check.
Summer, sun, beach or lawn: The hot days attract us outdoors. And every year, there are myths about sunscreen. Does a high sun protection factor (SPF) really make a difference? Does a vegan diet protect the skin? Does reapplying sunscreen extend sun protection? This fact check clarifies the truth.
Claim: Reapplying sunscreen extends sun protection.
Rating: False.
Facts: The German Federal Office for Radiation Protection advises applying sunscreen 20 to 30 minutes before sun exposure. To maintain the effectiveness of sunscreen, regular reapplication is necessary: "At least every two hours and especially after bathing and drying." However, this only works if the sunscreen actually lasts that long.
Dermatologist Christoph Liebich from Munich explains that reapplying sunscreen cannot extend the sun protection time in the sun. "For example, if I apply a factor ten sunscreen and have a sun protection time of ten minutes, it's over after 100 minutes. Then it doesn't help if I apply the ten or even the fifty after that." The sun has already penetrated the skin, and the sun protection time has been used up. Nevertheless, reapplying sunscreen in these cases is still sensible to maintain the existing protection.
It is necessary to apply enough sunscreen from the start: According to the German Federal Office for Radiation Protection, the sun protection factor for a sunscreen is valid for a surface area of two grams per square centimeter of skin. This corresponds to approximately four heaped teaspoons for the entire body of an adult.
Claim: A day cream is sufficient as a lighter sunscreen.
Rating: Sometimes correct.
Facts: For sun protection with a day cream, it is essential that it contains a UV filter. If this requirement is not met, there is no sun protection, as Kerstin Effers, consumer advisor for environmental and health protection at the North Rhine-Westphalian Consumer Center, points out. The sun protection factor should be indicated on the packaging. "Without this information, consumers cannot evaluate the protective effect for themselves," Effers says. Experts also recommend a high sun protection factor for day creams.
Additionally, it is just as important to use an adequate amount of day cream as with sunscreen. Dermatologist Liebich fears that some people may not apply enough of the expensive creams - after all, they are often considered a luxury product. "If the recommended amount is not applied, a lower protection factor offers even less protection," Liebich explains. Those who hesitate to use enough should opt for classic sunscreen instead.
Claim: Pre-tanning in a tanning bed protects the skin.
Rating: False.
Facts: When one lies in the sun or in a tanning bed, they receive ultraviolet radiation on their skin. In general, three types are distinguished: UVA, UVB, and UVC. UVA radiation is the part that penetrates into the leather skin (dermis). UVB rays, on the other hand, only affect the upper skin. UVC rays are so short-waved that they are already blocked by the ozone layer.
The tanning bed only causes a "dirty tan," which does not build a real protection, according to dermatologist Liebich. The light used in tanning beds mainly consists of UVA rays, which cause a quick but not lasting tan. UVB rays are often filtered out. "We need UVB rays for the protective effect, but they are banned in tanning beds," he explains.
In general, tanning causes UV radiation exposure. It is not without reason that tanning beds are forbidden for people under 18. "Any additional radiation is not good," emphasizes Liebich.
Claim: A vegan diet protects against sunburn.
Rating: False.
Facts: The idea that one can protect oneself from sunburn through a vegan diet is appealing. However, experts deny this. While the vitamin A and beta-carotene found in healthy food sources can provide a natural protection for the skin - including against the sun - this is not sufficient to protect the skin from sunburn at high UV indices.
Regarding beta-carotene, for example, fruits and vegetables are the most important sources for humans. Who eats a lot of them receives "secondary plant pigments that then simply additionally protect the skin from sunburn," explains Liebich. However, the basis must always be sunscreen, as the diet alone builds no real protective factor.
Claim: Sunscreen can expire.
Rating: True.
Facts: Sunscreen can also deteriorate. The fact that one should not leave creams and the like on for too long has several reasons. The protection against UV light decreases, which can lead to sunburn in the short term and increase the long-term risk of skin cancer. That's why manufacturers indicate how many months a sunscreen should be used after opening. A label with an "12M," for example, means twelve months. A note with the opening date on the bottle can help.
Additionally, benzophenone forms in many sunscreens over time. Researchers have discovered this in a study for the "American Chemical Society." Benzophenone forms from octocrylene. Many sunscreens contain this chemical because it protects against UVB rays. The researchers followed the aging of the product for a year. An intriguing finding and another reason to dispose of sunscreen from the previous year: Benzophenone can even form in unopened packages.
Despite the prevalence of myths, applying enough sunscreen from the start is crucial for effective sun protection. As advised by the German Federal Office for Radiation Protection, a sun protection factor (SPF) of two grams per square centimeter of skin is required for adequate protection, which corresponds to approximately four heaped teaspoons for an adult's entire body.
Contrary to popular belief, a day cream may provide sufficient sun protection if it contains a UV filter and carries a high SPF rating. However, it's essential to apply an adequate amount to ensure proper coverage, as some people may overlook this due to the luxury perception of day creams.
