Sunscreen

from Wikipedia, the free encyclopedia
A comparison between a recording in the UV range (right) and one in the visible spectrum (left) illustrates the function of a sunscreen.

Sun cream and other sun protection products are applied to the skin in order to reduce or prevent the negative effects of solar radiation (such as sunburn with reddening of the skin, blistering, skin aging). Statistics show an increasing risk of skin cancer , especially in people with "fair skin type " (types I to IV minimum), who often expose themselves to intense sunlight without protection. Sunburns are particularly critical in childhood. The UV rays of sunlight are considered to be the main cause of light-induced skin damage, which is why sunscreens protect against both UV-B and UV-A radiation .

It is recommended by professional associations to orientate oneself in one's behavior to the intensity of the sun exposure and the individual skin type . As a protective measure, the first priority is to avoid excessive UV exposure (from the sun and solariums), followed by "textile light protection" (with clothing and headgear). Sun protection preparations are recommended as a supplementary measure, but these must be applied generously and in good time. Waterproof products delay the washing off of the sunscreen and thus receive temporary protection during bathing, water sports or if you sweat heavily. The protection of the eyes with sunglasses is part of the overall concept of sun protection.

history

At the beginning of the 20th century, tanned skin was still a sign of the lower class (farm workers, seamen, road workers). In parallel to the industrial development, social change began in the 1920s with a move towards more light, air and sun. Between 1920 and 1930 a new swimwear with backless swimwear appeared, mostly seen as cheeky or even immoral. With more naked skin exposed to the sun, the problem of sunburn took on a new role. In addition, sports such as skiing and folding boating became popular in the 1920s, and some of these took place with very high solar intensity and reflection. In this environment, the first modern on was light stabilizers based sunscreen that Delial ointment , from the Bayer subsidiary DRUGOFA developed and introduced 1,933th In addition, the first documented use of sunscreen was in the United States in 1928 . The soon internationally successful Ambre Solaire followed in 1936 , presented by L'Oreal founder Eugène Schueller. And in 1938, while climbing Piz Buin, the Austrian chemistry student Franz Greiter got a bad sunburn and then developed a formula for a cream that should protect the skin from the sun in a small laboratory in his parents' house. A third brand was born, in 1946 Greiters Piz Buin came onto the market. As early as the 1920s, the Austrian Josef Maria Eder developed the sunscreen Antilux together with Leopold Freund. Parts of his research results were published in the Wiener Klinische Wochenschrift as early as 1922. The photo chemist Josef Maria Eder can therefore be seen as a pioneer in the development of sunscreens.

The bikini was introduced in 1946 . In the 1950s and 1960s, he set a new fashion trend as the trademark of Brigitte Bardot, and brown skin became a status symbol of the emerging industrial society. More and more people traveled to southern beaches to sunbathe there. The sunscreen, which was comparatively expensive at the time, was only used very sparingly and sunburns were common. With increasing prosperity, however, the sunscreen market continued to develop and today it has a variety of products in the form of milk, spray, cream, oil, stick, gel, foam, each with different sun protection factors.

The importance of the tan has changed significantly over the past two decades. Knowledge of the risks of excessive sunbathing (skin aging, skin cancer) has further developed sun protection in the direction of disease prevention . In addition to appropriate behavior and protection through textiles, sunscreens are now an important part of protecting the skin from the negative effects of solar radiation.

In 1956, the radiation physicist Rudolf Schulze from Hamburg introduced the term protection factor of the light protection agent , which was defined as light protection factor in 1962 by the Austrian chemist Franz Greiter . Initially, the sun protection factor was only used by dermatologists and only years later did it appear in product claims. The Piz Buin brand was a pioneer in the early 1960s with the introduction of this measure. The sun protection factor only really caught on when it was regularly used by Stiftung Warentest from 1966 to measure and evaluate product performance.

From the end of the 1980s, sun creams were fitted with tiny particle filters that built up a physical protective effect.

The technical development of sunscreens and the associated strength of the sun protection factors showed a development over the years. Today, the labeling of sun protection factors and all other statements on product performance is regulated by recommendations from the EU Commission , industry and scientific associations.

Product types

Sunscreen aerosol spray when applying

The most common sunscreens are liquid emulsions . The difference between the products sun cream, sun lotion (also called sun milk) and sun gel is the composition or the way in which the different ingredients are dissolved. This is particularly noticeable for the user in the consistency.

Lotions mainly consist of O / W emulsions (oil-in-water) and therefore have a lower proportion of fats or oils and a higher proportion of water, which is why lotions are more liquid than creams that are used as W / O emulsions (water -in-oil). However, because of their comparatively greasy character, creams have particularly high water resistance and thus resistance to washing off the sunscreen while bathing.

Lotions and gels can also contain alcohol. However, gels are completely free of fat.

According to the applicable EU directive, only the four sun protection factor classes basic , medium , high and very high as well as eight sun protection factors are offered: 6 and 10 (basic); 15, 20 and 25 (medium); 30 and 50 (high); 50+ (very high). Products with sun protection factors below 6 are no longer assigned to sunscreens, as the main purpose of the products (sunscreen) is not fulfilled due to the low protective effect. The previously used product name Sunblocker is also no longer used because the consumer could mistakenly assume complete protection.

The liquid emulsions segment continues to play an important role in the market. There are also oils, foams, pens, aerosols, as well as products for use after sunbathing ( aftersun products) and self-tanning agents .

ingredients

In addition to water and light protection substances, sunscreens also contain fatty acids, di- and triacylglycerides , fatty alcohols , silicone oils (as emulsifiers), glycerine or propylene glycol (humectants) and special active ingredients ( antioxidants ). Other components serve as solvents for light stabilizers (oil components), to achieve the necessary rheological (flow) properties (thickener) or branding (perfume). Sun protection preparations contain comparatively high amounts of specific light protection substances (light protection agents) in a cosmetic preparation base. A high sun protection factor tends to require a high proportion of sun protection substances, but this can lead to noticeable residues on the skin and therefore to a lack of acceptance. But microplastics are also found in many sunscreens.

Sun protection filter

According to European law, light protection agents are defined by their intended use. Accordingly, they are "substances that are exclusively or predominantly intended to protect the skin against certain UV radiation by absorption, reflection or scattering of certain UV radiation". Regardless of whether they are organic or inorganic, so-called chemical or physical, natural or artificial light protection agents, all light protection agents are assigned to this definition. Only those sunscreens may be used that are listed in the German Cosmetics Ordinance . Since the individual substances usually do not offer protection across the entire UV spectrum, several substances are usually combined. In addition, the combination of light stabilizers usually results in synergistic effects.

After the products have been applied, light stabilizers diffuse into the horny layer and together with it form a protective film. They work immediately after application, but full protection takes a few minutes to develop. It is therefore particularly important to apply sun protection products in good time before sunbathing. Some preparations also contain antioxidants (such as vitamin E , vitamin C ), which are supposed to weaken the secondary reactions of UV exposure (oxidative stress due to oxygen radicals).

In sun creams, nanotechnology is also being used more and more frequently for the physical and chemical sunscreens . In particular, the two mineral sunscreens titanium dioxide (Titanium Dioxide) and zinc oxide (Zinc Oxide) are used in sun creams with nanoparticles. The nanoparticles have a positive effect on the texture of the sun cream, they scatter the light in different directions and prevent a film from becoming visible on the skin. The tiny particles make the cream easier to spread on the skin and appear transparent.

effect

Prophylaxis of skin diseases

To simplify matters, cosmetic sun protection products can be viewed as a means of reducing the amount of UV radiation penetrating the skin. They are used externally to protect the skin from the negative effects of solar radiation. A distinction is made between acute (immediately occurring) and chronic (later occurring) skin changes. Sunburn, often associated with reddening of the skin, blistering and burn pain, is the most important acute consequence of excessive sun exposure. Skin aging (wrinkling, pigmentation disorders) and in extreme cases skin cancer can occur as long-term consequences.

After use, the sunscreens supplement and expand the skin's natural protection. This self-protection essentially consists of the horny layer of the epidermis (stratum corneum) and the skin tan (pigmentation). Under UV radiation, the rate of cell division increases and the horny layer thickens ( light callus ). At the same time, the production of brown skin pigments ( melanin ) in the corresponding cells ( melanocytes ) is stimulated. The self-protection of the skin increases with the thickness of the horny layer and with increasing skin tan.

This varies greatly from person to person and depends on the (genetically determined) skin type and the gain acquired through sun exposure. The light, often freckled skin of the red-haired northern Europeans is particularly sensitive . Dark-skinned (often also dark-haired) southern Europeans are rather insensitive. The UV sensitivity of skin that is used to the sun at the end of summer is usually significantly lower than that of skin that is used to the sun in spring.

Studies

In addition to other measures, sunscreens are believed to be an effective means of preventing sunburn . The data on how effectively they can prevent chronic damage to the skin is less clear. There are well-founded data in vitro and on animal models on the effectiveness of preventing light aging of the skin , but only a few studies that show a benefit in humans. The data situation is also heterogeneous when it comes to avoiding ( primary prophylaxis ) the various skin cancers that can result from exposure to UV radiation. While there are a limited number of studies on the reduction of actinic keratosis , basal cell carcinoma and spinocellular carcinoma , the data for malignant melanoma are contradicting or no benefit can be shown. Malignant melanoma is by far the rarest of the three skin cancers, but it is less curable and causes 75% of deaths.

The German Cancer Aid , the German Cancer Society and dermatological societies see sunscreens as a useful addition to other methods of sun protection (avoiding direct sun, looking for shade, clothing, headgear), but not as the sole measure to avoid UV-indicated skin damage.

A new study has shown that a medium to high sun protection factor (> 15) reduced the risk of developing malignant melanoma by around 33%. Paradoxically, in an epidemiological study conducted in Norway, the risk of developing malignant melanoma increased when a lower sun protection factor (<15) was used. This is probably due to the fact that people who use sunscreen to protect themselves are exposed to a cell-damaging dose of UV rays despite all the risks. A high sun protection factor seems to significantly offset this risk. In addition, researchers still criticize that the amount of sunscreen applied is often too small.

The number of skin cancer cases in Germany has doubled in the last ten years to 2013 to 234,000 new skin cancer cases per year. The diseases are distributed among basal cell carcinoma 137,000, squamous cell carcinoma 70,000 and black skin cancer with around 28,000 people. The skin of children and adolescents is particularly sensitive to UV rays. According to epidemiological studies, adolescents who were often exposed to the sun in their childhood and who suffered sunburns have a significantly higher risk of developing skin cancer later on, particularly malignant melanoma. The German Cancer Aid and the Cancer Society provide information material free of charge, including UV protection tips for babies and children.

Sun protection factor

The world's most important criterion for assessing the effectiveness of sunscreen is the SPF (SPF, Sun Protection Factor or SPF). It is calculated from the ratio of the MED of (by sunscreen) protected to unprotected skin (MED = minimum erythema dose; corresponds to the minimum dose until the skin becomes reddened). A high SPF stands for a high level of protection against erythema-causing radiation and a low SPF for a correspondingly lower level of protection. The SPF allows the consumer to directly compare the protective performance of sunscreens.

The UVA signet used in the EU

The SPF is determined according to the COLIPA International Sun Protection Factor Test Method , whereby the increase in the skin reddening threshold ( minimum erythema dose , MED) is determined after standardized application of light protection preparations . According to the definition, the sun protection factor only indicates the protective effect of a product against erythema-causing radiation. This is mainly the UV-B part of sunlight. To protect against other skin damage caused by light, sunscreens must also protect against UV-A radiation. Therefore, criteria for minimum effectiveness against UV-B and UV-A radiation have been applied to sunscreens in Europe since 2006.

  • Sun protection factor (SPF): The sun protection factor of a sunscreen should be at least 6.
  • UV-A protection factor (UV-A-PF): The UV-A protection factor should be at least one third of the sun protection factor.
  • Broadband spectrum protection: Only with this name does a sunscreen guarantee protection against UVB rays.

A sunscreen with an SPF of 30 should therefore have a UV-A protection factor (UV-A-PF) of at least 10. To test the UV-A protection factor, COLIPA issued a recommendation for in-vitro testing. Compliance with the required UVA protection is indicated on the packaging by a symbol. It consists of a circle containing the letter combination "UVA". UVB rays are considered to be the main cause of skin cancer, which is on the rise worldwide. Broadband protection against UVA and UVB is therefore essential.

According to the definition that is valid today, the sun protection products with protection factor 2 or 4, which used to be very popular, are no longer sun protection products because they do not fulfill the predominant purpose (= sun protection). For a better understanding, one of the four assigned protection classes is indicated on the packaging in addition to the sun protection factor (low, medium, high, very high).

Product category / protection class Protection factor / permitted information (EU, EFTA status 2012)
Low 6, 10
medium 15, 20, 25 *
High 30, 50
Very high 50+

* SPF 25 is the legal minimum sunscreen factor in Australia / New Zealand and Canada. The specification of the protection factors on the packaging is limited to the specified values.

From 2013, protective designations will be supplemented by the P + to P +++++. The water resistance is tested by independent institutes according to a uniform protocol. This standard will be introduced in the USA from 2013 and will soon also be visible in Europe thanks to products sold worldwide. The long-term waiver of protection factor designations is planned as this misleads the consumer.

SPF50 + is mistakenly understood as a sun blocker . However, an SPF 50 only offers 98% and SPF15 94% protection against UVA and UVB rays. However, a common perception is that SPF50 almost completely protects what is incorrect. The European Commission for Health therefore recommends applying SPF15 to SPF25 repeatedly and in particular in sufficient quantities.

Side effects

Side effects of sun protection preparations can be irritation, allergic or photoallergic reactions of the skin.

For certain ingredients, an estrogen-like activity has been shown in animal experiments , but this is not classified as relevant for humans. Only the light stabilizer 4-methylbenzylidene camphor should be avoided, as the suspicion of harmfulness could not be refuted.

Another possible side effect was a negative influence on the vitamin D 3 and calcium balance . However, no effect could be shown even with long-term use of sunscreens. Certain light protection agents can also have neurotoxic effects at high concentrations.

The possibility that the use of sunscreen may even increase the risk of developing malignant melanoma is controversial. While some epidemiological studies have come to this conclusion, reviews cannot show this relationship. One of these papers criticizes the insufficient consideration of hidden disturbing effects (so-called confounder effects) as well as sun creams with a protection factor greater than 15 and with protection against UV-A radiation or water resistance, which are recommended as standard today. Prolonged exposure to the sun after using sunscreen may also play a role in generating this data.

Prohibitions

On November 2, 2018, the President of Palau , Thomas Remengesau , approved a law that had already been passed by Parliament, which bans certain sunscreens that are harmful to coral reefs from 2020. Sunscreens that contain oxybenzone and octinoxate , which contribute to coral bleaching , are affected . The import of these creams should be prohibited and their use made a criminal offense. Palau is the first country in the world to ban sunscreen substances that are harmful to corals, previously announced by the US state of Hawaii and the Caribbean island of Bonaire , which belongs to the Netherlands .

literature

  • Peter Finkel: Sunscreens . In: Wilfried Umbach (Ed.): Cosmetics and hygiene from head to toe . 3rd, completely revised and expanded edition. Wiley-VCH, Weinheim 2004, ISBN 978-3-527-30996-2 , pp. 157-173.

Web links

Commons : Sunscreen  - Collection of pictures, videos, and audio files

Individual evidence

  1. ↑ a b c d e f g Daily light protection in the prevention of chronic UV damage to the skin ( Memento from June 15, 2008 in the Internet Archive ) German Society for Dermatology, AWMF Online, 11/2005
  2. ↑ Dieter Wildt: Sun cult . Econ Verlag, Düsseldorf 1987, ISBN 3-430-19676-0 .
  3. ↑ Darrell S. Rigel, Robert A. Weiss, Henry W. Lim, Jeffrey S. Dover: Photoaging . Ed .: Darrell S. Rigel, Robert A. Weiss, Henry W. Lim, Jeffrey S. Dover. CRC Press, 2004, ISBN 978-0-8247-5209-5 , pp. 73-74 .
  4. ↑ loreal.de
  5. ↑ Kristine von Soden: When tan came into fashion. In: Hamburger Abendblatt. August 13, 2012, accessed August 17, 2018 .
  6. ↑ Josef Maria Eder & Leopold Freund: A new means of protection against photodamage. In: Wiener Klinische Wochenschrift. 1922
  7. ^ Photograph with the title "Boy as a test object for the sunscreen Antilux developed by Josef Maria Eder together with Leopold Freund"
  8. ^ Wilfried Umbach: Cosmetics and hygiene. 3. Edition. Wiley-VCH Verlag, Weinheim 2004, ISBN 3-527-30996-9 , p. 157 ff.
  9. ^ F. Urbach: Franz Greiter - The Man and His Work . In: Photobiology . Springer US, 1991, ISBN 978-1-4613-6661-4 , pp. 761-761 , doi : 10.1007 / 978-1-4615-3732-8_82 .
  10. ↑ a b Wilfried Umbach: Cosmetics - Development, manufacture and use of cosmetic products. 2nd Edition. Georg Thieme Verlag, Stuttgart 1995, ISBN 3-13-712602-9 , p. 147 ff.
  11. ↑ J. Lendenmann: Suns. In: Vista. 3, 2003, p. 7 (PDF; 632 kB).
  12. ↑ Stiftung Warentest: Test 1 . Issue 3, Volume 32, 1966.
  13. ↑ Sommerhitze1933: sunscreen, a girl thing. In: Focus Online. Retrieved April 16, 2018 .
  14. ↑ Peter Finkel: Cosmetic light protection agents. In: SÖFW-Journal. 126th year 2000, issue 7, pp. 16-20.
  15. ^ Peter Finkel: Sun protection, Cosmetics International . Issue 4, 2008, pp. 140-142.
  16. ^ Wilfried Umbach: Cosmetics and hygiene. 3. Edition. WILEY-VCH, Weinheim 3004, pp. 165-170.
  17. ^ KR Johnson: Sunburn. In: Review, UpToDate. Version January 31, 2008.
  18. ^ MF Demierre, AC Geller: Primary prevention of melanoma. In: Review, UpToDate. Version January 31, 2008.
  19. ^ O. Gefeller, A. Pfahlberg: Sunscreen use and melanoma: a case of evidence-based prevention? In: Photodermatology, Photoimmunology & Photomedicine . 2002 Jun; 18 (3), pp. 153-156; PMID 12207681 .
  20. ↑ L. Goldsmith et al. a .: Proceedings from the national conference to develop a national skin cancer agenda. American Academy of Dermatology and Centers for Disease Control and Prevention. April 8-10, 1995. In: J Am Acad Dermatol. 1996 May; 34 (5 Pt 1), pp. 822-823. PMID 8632080 (quoted from: Demierre MF, Geller AC: Primary prevention of melanoma. UpToDate, version January 31, 2008).
  21. ^ Institute for Occupational Safety and Health of the German Statutory Accident Insurance (IFA): Suitability of sunscreens for skin cancer prevention . BGIA report 3/2006.
  22. ↑ Reza Ghiasvand, Elisabete Weiderpass, Adele C. Green, Eiliv Lund, Marit B. Veierød: Sunscreen Use and Subsequent Melanoma Risk: A Population-Based Cohort Study . In: Journal of Clinical Oncology . September 12, 2016, ISSN  0732-183X , p. JCO675934 , doi : 10.1200 / JCO.2016.67.5934 , PMID 27621396 ( ascopubs.org [accessed September 14, 2016]).
  23. ↑ Current skin cancer statistics 2013, Deutsche Krebshilfe , Bonn, May 2013.
  24. ↑ Eckhard Breitbart, Dermatological Prevention Working Group (ADP), May 14, 2013.
  25. ↑ a b haut.de
  26. ↑ Page no longer available , search in web archives: International Sun Protection Factor (SPF) Test Method. 2006. (PDF; 1.3 MB) COLIPA@1@ 2Template: Dead Link / www.colipa.com
  27. ↑ colipa.eu
  28. ↑ ipa.ruhr-uni-bochum.de (PDF)
  29. ↑ Information, tips and recommendations on sunscreens. Opinion No. 035/2005 of the Federal Institute for Risk Assessment of August 22, 2005.
  30. ↑ Joanna A. Ruszkiewicz, Adi Pinkas, Beatriz Ferrer, Tanara V. Peres, Aristides Tsatsakis, Michael Aschner: Neurotoxic effect of active ingredients in sunscreen products, a contemporary review. In: Toxicology Reports . 4, 2017, pp. 245-259, doi: 10.1016 / j.toxrep.2017.05.006 .
  31. ↑ C. Garland, F. Garland, E. Gorham: Could sunscreens increase melanoma risk? In: Am J Public Health . 1992, 82 (4), pp. 614-615; PMID 1546792 .
  32. ↑ P. Autier et al. a .: Melanoma and use of sunscreens: an Eortc case-control study in Germany, Belgium and France. The EORTC Melanoma Cooperative Group. In: Int J Cancer . 1995 Jun 9; 61 (6), pp. 749-755; PMID 7790106 .
  33. ↑ M. Huncharek, B. Kupelnick: Use of topical sunscreens and the risk of malignant melanoma: a meta-analysis of 9067 patients from 11 case-control studies. In: Am J Public Health. 2002 Jul; 92 (7), pp. 1173-1177. PMID 12084704 .
  34. ^ A b L.K. Dennis, Beane Freeman LE, VanBeek MJ: Sunscreen use and the risk for melanoma: a quantitative review. In: Ann Intern Med . 2003 Dec 16; 139 (12), pp. 966-978; PMID 14678916 .
  35. ↑ Holiday paradise protects corals - Palau bans most of the sun creams. In: n-tv . November 2, 2018, accessed November 2, 2018 .