Sunscreen myths put to the test Does a high sun protection factor provide better protection?
When the sun is really burning, protection from the tube should actually be indispensable. But year after year, various claims circulate about the effects of sun cream. A fact check.
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- Summer, sun, beach: the hot days lure us to the beach. And, as every year, myths about sun cream become popular.
- Does a high sun protection factor really help more? Does a vegan diet help to protect the skin? Does reapplying sunscreen prolong sun protection?
- This fact check shows what is true.
Claim 1: Reapplying sunscreen prolongs sun protection.
Assessment: False.
The Federal Office for Radiation Protection advises applying sun cream 20 to 30 minutes before going out in the sun. To maintain the protective effect of the sun cream, it is important to reapply it regularly: "At least every two hours and especially after bathing and drying off." The prerequisite is that the sun protection lasts this long in the first place.
This is because reapplying cream cannot extend the protection time in the sun, explains dermatologist Christoph Liebich from Munich. "For example, if I apply a protection factor of ten and have a self-protection time of ten minutes, it's over after 100 minutes. Then it won't help if I reapply the ten or even the fifty." The radiation has already penetrated the skin and the protection time is exhausted. Nevertheless, it makes sense to reapply cream in the cases indicated in order to maintain the existing protection.
It is necessary to apply enough sun cream right from the start: according to the Federal Office for Radiation Protection, the sun protection factor is two milligrams per square centimeter of skin. For an adult, this corresponds to about four heaped tablespoons for the whole body.
Claim 2: A day cream is sufficient as light sun protection.
Assessment: Correct in some cases.
For a day cream to provide sun protection, it is essential that it contains a UV filter at all. If this requirement is not met, there is of course no sun protection, emphasizes Kerstin Effers, environmental and health protection officer at the North Rhine-Westphalian consumer advice center. The sun protection factor should be stated on the packaging. "Without this information, it is impossible for consumers to assess the protective effect," says Effers. Experts also recommend a high sun protection factor for day creams.
In addition, it is just as important to use a sufficient amount of day cream as sun cream. Dermatologist Liebich fears that some people may not apply enough of expensive creams to their face - after all, it is often a luxury product. "If you don't apply the recommended amount, a low protection factor offers even less protection," explains Liebich. If you are hesitant to use enough, it is better to use classic sun cream.
Claim 3: Pre-tanning in a solarium protects the skin.
Assessment: False.
If you lie in the sun or in a solarium, your skin is exposed to ultraviolet radiation. A basic distinction is made between three types: UVA, UVB and UVC. UVA radiation is the part of the radiation that reaches the dermis. UVB rays, on the other hand, only affect the epidermis. UVC rays are so short-wave that they are intercepted by the ozone layer.
According to dermatologist Liebich, the sunbed only provides a "dirty tan" that does not build up any real protection. The light used in sunbeds consists mainly of UVA rays, which provide a quick but not permanent tan. UVB radiation is often filtered out. "To build up protection, we also need a UVB component, but this is prohibited in sunbeds."
Generally speaking, pre-tanning in a solarium results in radiation exposure. It is not without reason that tanning beds are prohibited for people under the age of 18. "Any additional radiation is not good," emphasizes Liebich.
Claim 4: A vegan diet protects against sunburn.
Assessment: False.
Protecting yourself from tanning with a vegan diet - that sounds tempting. But experts deny this. According to the Federal Association of German Pharmacists (ABDA), the vitamin A and beta-carotene mainly found in healthy foods can provide natural protection for the skin - including from the sun. However, this alone is not sufficient to protect the skin from sunburn when the UV index is high.
When it comes to beta-carotenes, for example, vegetables and fruit are the most important sources for humans. If you eat a lot of them, you get "secondary plant pigments, which then simply protect the skin from sunburn", explains Liebich. However, the basis must always be sun cream, as nutrition alone does not build up a proper protection factor, says the dermatologist.
Claim 5: Sun cream can deteriorate.
Assessment: Correct.
Sunscreens can also go bad. There are several reasons why you shouldn't keep creams and the like for too long. The protection against UV light diminishes. This can lead to sunburn in the short term and increase the risk of skin cancer in the long term. This is why manufacturers indicate how many months a sunscreen product should be used after opening. This is indicated by a small symbol with a number and an "M". For example, "12M" means twelve months. A note with the opening date on the bottle can help.
In addition, the potentially carcinogenic benzophenone builds up in many sun creams over time. This was discovered by researchers in a study for the American Chemical Society. Benzophenone is gradually formed from octocrylene. Many sun creams contain this chemical because it protects against UVB radiation. In the experiment, the researchers simulated the ageing of the product over a period of one year. What is striking about this and another reason to dispose of last year's sun cream is that benzophenone can even develop in unopened packs.
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