Solar damage: challenges and opportunities for future photoprotection

A group consisting of seven of the most prestigious dermatologists specialists in photo-dermatology and experts in regulatory matters from around the world, led by the professor Jean Krutmann, have written a scientific article on positioning, published in January of this year in the Journal of the European Academy of Dermatology and Venereology, in which they analyze the current state of photoprotection and discuss how it should be in the future. Its objective is to inform health professionals about the characteristics that it should fulfill the 'ideal photoprotector', as well as suggestions for Health Authorities to improve the regulations that assess the level of sun protection, in order to avoid inter-laboratory variability and improve the labeling of photoprotectors.

Dermatologists recognize that due to scientific advances on the effect of solar radiation on the skin and in the formulation of photoprotectors, they face new challenges. In recent years, an excess of information has emerged in some cases with little scientific foundation, which has generated doubts in the general population, regarding the safety and efficacy of sunscreens. In this article, the authors position themselves on issues directly related to the effect of solar radiation on the skin, improved and alternative evaluation methods or how to improve consumer communication about the effectiveness of sun protection. But also issues that go beyond such as the environmental impact of photoprotectors, the potential of oral photoprotectors or the need to improve therapeutic adherence thanks to innovative galenic formulations.

Manufacturers should adapt the products to the appropriate amount of filters and that they are respectful of the marine environment

How can a user know the degree of sun protection according to the indications of the package? What methods do manufacturers use to measure the level of protection? Should protection be the same on lighter skin than darker skin? How can you customize a photoprotector? There are many questions about photoprotection and no doubt, according to experts, there is a lot of confusion in the public and possibly also among healthcare professionals.

The review article ‘Photoprotection of the future. Challenges and opportunities’Intends to give a clear message explaining these concepts in a simple way and offering concrete recommendations on how the photoprotection and the ideal photoprotector of the future should be. Although there are two methods of evaluation of the Sun Protection Factor, ISO 24444: 2010 method and the 2011 FDA monograph, the variability of the Sun Protection Factor or SPF for its acronym in English (Sun Protection Factor) It is one of the main controversies. Ideally, according to experts, it would be a review and improvement according to new knowledge. The ISO 24444/2010 method determines ‘in vivo’ the SPF to establish the degree of sun protection, by calculating the minimum dose that produces redness –erythema– on skin protected from that not protected by a photoprotector.

What does the study say?

The authors assure that there is ample scientific evidence which indicate the variability depending on the laboratory that performs it. This is because in order to determine erythema a specialist laboratory technician visually determines the minimum erythematic dose of protected skin and unprotected skin. That is to say, it is a determination that is made 'by eye' (minimum dose of radiation that produces erythema). In addition, according to the ISO standard, volunteers are subjected to very high doses of radiation in a very short time but this may vary according to laboratories.

The growing concern for the environment causes some people to stop using photoprotection for alarming news

A dose of 2 mg / cm2 of the photoprotector is administered when in real conditions of use the users use a much smaller dose, half or a quarter. In conclusion, "the determination of SPF in laboratories is very different from the actual conditions of use," notes the Dr. Aurora Garre (Medical Marketing Manager of ISDIN). ANDThis test standard has been carried out for ten years and innovation in formulas seems to have gone faster than regulations. Experts indicate that the variability of results should be avoided by controlling these factors, therefore they urge regulatory authorities to revise the standard, although as long as it does not change it is still the best standardized method for cataloging the protective action of a photoprotector.

The authors of the article also point out that these studies are carried out in laboratory conditions, very different from the actual conditions of use. In this sense, and as explained by Dr. Garre, “You could also do outdoor studies ('outdoor') because they help to understand that two products with the same SPF can behave differently since other factors such as sweating, body temperature and other radiation in addition to ultraviolet radiation, such as blue light and infrared radiation are involved " Experts indicate that outdoor studies provide added value but also have many limitations to avoid variability. Consequently, standards should be set (ultraviolet index, weather conditions, …).

In any case, they could be complementary to the determination of SPF in the laboratory. Currently the European ISO standard is being changed, in order to find A method that is more objective. The authors affirm that “it would be important to introduce changes that limit the sources of variability, for example, the use of specific methodologies to determine phototypes and the appearance of erythema in an objective way. ”

But there is another UV radiation, ultraviolet A, which does not cause erythema but in the long term causes premature skin aging, spots, immune disorders or skin cancer. Users do not know what degree of UVA protection a photoprotector provides. In Europe, its value is one third or more of the SPF when written within a circle. The authors of the article indicate that the real importance of this radiation is not being given and an agreement should be reached on how to transmit the degree of UVA protection.

And the blue light?

The group of experts talk about the importance of also protecting themselves from blue light, especially in the darkest phototypes, since it produces increased pigmentation in a more lasting way. "We must protect ourselves from all the radiation of the solar spectrum that affects our skin considering that its amount varies throughout the year," says Dr. Garre. This is what experts indicate as balanced, balanced photoprotection. In summary. Should we protect ourselves from UVB, UVA and blue light? Yes. How much? The consumer needs more information.

Product safety

Since the 50s that the first sunscreens were marketed, no systemic adverse effects have been described by the use of a photoprotector. And this means that they are safe products. A doubt has been generated in the population because at the beginning of 2019 a publication appeared that indicated that the photoprotectors applied to the skin could cross and reach the blood, which could pose a health risk. This generated a social alarm but experts indicate that it is not extrapolated to the actual conditions of use since in this study The photoprotector is applied in 75% of the body surface and at maximum doses. Either way, there is no evidence on what its impact would be.

As for the textures, its evolution has been enormous in recent years. These advances have the purpose that users wish to use the product, thus improving adhesion, that is, applying every two hours and abundantly (at the appropriate doses of 2 mg / cm2). Therefore, manufacturers should tend to a range of products adapted to each type of skin and conditions of use.

Sunscreen products with added benefits for skin care, such as rejuvenating or anti-aging properties are needed

The growing concerns of the population Because of the environment, it makes some people sensitive to this issue stop using photoprotection due to the alarming news that some filters may affect the marine environment. The authors indicate that, although the available scientific information is still scarce, manufacturers should adapt the products using the appropriate amount of filters and that these are respectful With the marine environment. As conclusions, Dr. Krutmann affirms that "the ideal photoprotector is one that provides balanced, safe and easy to use protection." This can be achieved through the following steps:

• SPF determination methods They should evolve to avoid variability. For the determination of SPF, alternative evaluation variables other than erythema should be considered, reflecting both acute and chronic damage.
• Photoprotection should include protection against wavelengths beyond UV rays.
• Photoprotection must be balanced and must take into account the interactions between different wavelengths in natural sunlight.
• Efforts must be made to develop specific / customized sunscreens for different population subgroups with different protection needs.
• Continuous efforts should be made to improve compliance with the regular use of sunscreen by improving textures, skin sensation and administration systems.
• From a security perspective, the concentration of UV filters should be as low as possible and sunscreens must be formulated to have a minimal environmental impact.
• This can be partially achieved with innovative ingredients to complement the protection provided by UV filters.
• Sunscreen products with additional skin care benefits, such as hydration and rejuvenating or anti-aging properties, are needed to further encourage regular use by simplifying the skincare routine.