- Dermatology: how sunscreens work
Swimsuit, towel, glasses ... and sunscreen. But which one do I choose? It is likely that, following recent news, this year you have had doubts when choosing a photoprotector.
The Organization of Consumers and Users (OCU) set off the alarms a few months ago, when it asked the Spanish Agency for Medicines and Health Products (Aemps) to remove two sun creams claiming that the sun protection factor (SPF) indicated In the package it was superior to what they really had.
The Spanish Agency for Medicines and Health Products dismissed the petition shortly after and ratified the validity of the labeling of products that had been questioned. However, the controversy has sown uncertainty among consumers, which raise many questions: what is the SPF? How is it regulated? Who sets it? Can I trust what is in the market?
Photoprotectors are cosmetic formulas of different types whose purpose is to minimize the effects of solar radiation on the skin. The sun protection factor (SPF) is a number used to establish the ability of a product to reduce the effects of ultraviolet B (UVB) radiation. "It establishes the relationship between the minimum erythematogenic dose [burn] that is produced on the skin by applying a protector with respect to that produced on the same skin without applying it," explains Mª Jesús Lucero, professor at the Faculty of Pharmacy of the University of Seville and one of the most reputed voices in the country in Dermopharmacy.
Manuel E. García Fernández, a member of the official Association of Pharmacists of Mala, gives a clear example: "A product with SPF10 would withstand 10 times more radiation before producing a skin rash than if there was no protection."
As Lucero explains, in addition to Royal Decree 1,223 / 2009 on cosmetic products, the norm that regulates the effectiveness of photoprotectors in Spain is a recommendation of the European Commission (2006/647 / EC) - that "all or almost all laboratories follow as if it were mandatory . "
In that sense, for the trials aimed at evaluating efficacy, the standards set out in ISO-24,444: 2010 are followed, which establish that clinical trials are auditable and transparent.
As García Fernández points out, although there are different evaluation methods and each company can make the checks it deems necessary for its products, the recommendations of the European Commission state that "the degree of protection must be measured by reproducible methods, having take into account photodegradation. "
The Spanish employer of cosmetics and perfumery, Stanpa, describes this 2006 regulation as "revolutionary at that time", because, in her opinion, "she harmonized the numbers that the products put in the SPF and the criteria to establish them." Stanpa acknowledges that until that moment "the dispersion of criteria was large and consumers, who were learning to use sunscreens, could not have a clear idea about the levels of protection ."
Stanpa insists that today consumers can rest easy: "an SPF 30 protector blocks 97% of UVB rays and from 50+ 98% of UVB rays are blocked."
However, both the industry and experts agree that it is not beneficial to give messages of total or 100% protection , as consumers may have a false sense of security and relax in the sun. "The most important thing together with sunscreen is not to expose oneself in the hours of greater intensity, to be in the shade, to wear a hat, shirt and sunglasses depending on the situations, to hydrate well and reapply every two hours," said sources of the cited employer.
In addition, thinking about SPF is not the only important thing, Lucero agrees, since it reduces UVB radiation, but does not refer to UVA rays, which are also harmful.
It should also be taken into account that it is necessary to reapply the photoprotection periodically - also after bathing - and apply about 2 mg of product for every square centimeter of the skin, experts say.
"The determined determinations guarantee the sun protection of a cosmetic product. But the consumer must follow the instructions that the health authorities indicate and, above all, be generous with the amount of product that applies, " concludes Lucero.
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