By Marina Le Lamer
(Pharmacist, Production manager / Research and Development formulator at Corpa Flora)
Beach, pool, hike, picnic by the lake... As soon as the first rays of sunlight hit our skin, our summer weekends are filled with outdoor activities. In our backpacks, we carry with us this season's must-have: sun protection! But do you know exactly what it contains and if it is safe for your health and the environment? Come on, follow us, we explain everything.
THE SUN, FRIEND OR FOE?
The sun has several beneficial effects on our body:
- The synthesis of vitamin D, which is essential for the preservation of bone capital and the prevention of osteoporosis. A daily exposure of 15 minutes of the hands, forearms and face is usually sufficient to cover our needs in vitamin D. But don't hesitate to consult your doctor for personalized advice.
- Regulation of the internal clock through melatonin, the sleep hormone, whose synthesis follows a cycle depending on the capture of light in the retina of the eye.
- Stimulation of the well-being hormones (dopamine and serotonin) which leads to good mood, energy, optimism and dynamism.
- Improvement of the symptoms of certain skin conditions such as psoriasis or vitiligo.
The benefits of the sun are nevertheless less important than its harmful effects:
- Sunburn, burns
- Premature skin aging
- Skin cancer (melanoma, carcinoma)
It is therefore very important to protect your skin from the sun and to adopt the right habits:
- Choose the shade and go out in the morning or at the end of the day,
- Wear loose-fitting, covering clothing, glasses and a wide-brimmed hat,
- Reapply sun cream at least every 2 hours without waiting for it to heat up (the anti-inflammatory ingredients in the cream delay the burning sensation), but also after each bath or physical activity.
HOW TO CHOOSE THE BEST SUN CREAM ?
SPF INDEX : Guarantee of effectiveness
The best sunscreen is above all a stable and effective sunscreen, i.e. a broad-spectrum sunscreen that offers optimal protection against ultraviolet A and B rays (UVA and UVB). And for that, it is absolutely necessary to check that it has an SPF (Sun Protection Factor), measured by an independent laboratory.
The SPF defines the protection against UVB. For a given SPF, the amount of UVB (in %) that remains unfiltered = 100/SPF. A sunscreen SPF 20 lets 5% of UVB through and retains 95%, while a sunscreen SPF 50 lets 2% through and retains 98%.
Each SPF index also guarantees protection against UVA rays equal to at least a third of the protection against UVB rays. This means that for an SPF of 30 (UVB protection of 30), a minimum of 10 is expected for UVA protection.
However, you should know that no sunscreen product can guarantee total protection against UV rays and filter them out at 100%: there is no such thing as a total screen sunscreen.
SUNSCREENS: Impact on health and the environment
There are 2 categories of sun filters: chemical filters (also called "organic") and physical filters (or "mineral").
Chemical filters are synthetic molecules derived from petrochemicals. They penetrate the epidermis and absorb part of the UV radiation. They only become active 20 to 30 minutes after application. In recent years, several scientific studies have questioned their use because of their potential health risks. These chemical filters can be allergenic and irritating. Some, like oxybenzone (benzophenone-3) or octinoxate (ethylhexyl methoxycinnamate), are suspected of being endocrine disruptors, or even carcinogens.
In addition, these molecules are harmful to coral reefs and the marine ecosystem they support. They disrupt the reproduction and growth cycle of corals, leading to their bleaching. Each year, nearly 14,000 tons of sunscreen end up in the oceans (after our baths or after rinsing in the shower)! The negative impact on biodiversity is such that Hawaii has banned the sale of sunscreen containing oxybenzone or octinoxate since January 1st 2021.
Physical filters (zinc oxide and titanium dioxide) are inert and opaque mineral powders. They form a shield on the surface of the skin that reflects UV rays, like a mirror, and act immediately after application. They are the only filters authorized in the sun creams labeled organic. They have a good skin tolerance, however they are sometimes found in nanoparticulate form to obtain a light, transparent texture that does not leave a white film on the skin. At present, many doubts and uncertainties surround nanoparticles. Their effects on our health and on aquatic environments are very controversial within the scientific community. As a precaution, it is therefore preferable to avoid the mention [nano] which is specified on the list of ingredients.
INCI list: dissect it closely
Other problematic ingredients are very often found in the composition of sunscreens (preservatives, stabilizers, perfumes, mineral oils, silicones...). Some of them are suspected of being a health risk, others are polluting and destructive to biodiversity. It is therefore strongly recommended to always analyze the INCI list (the International Nomenclature of Cosmetic Ingredients) which is compulsorily written on the product.
You now have all the information you need to make a well-informed and well-reasoned choice about your sun protection, so you can enjoy the summer in complete peace of mind!
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- F.M Peinado et al., Cosmetic and personal care product use, urinary levels of parabens and benzophenones, and risk of endometriosis: results from the EndEA study. Environmental Research, 2020. Oct 16:110342.
- C.G Santamaria et al., Dermal exposure to the UV filter benzophenone-3 during early pregnancy affects fetal growth and sex ratio of the progeny in mice. Archives of Toxicology, 2020, 94: 2847-2859.
- European SCCS (Scientific Committee on Consumer Safety), Opinion on ZnO (nano form), 2012. https://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_103.pdf
- European SCCS (Scientific Committee on Consumer Safety), Opinion on Titanium Dioxide (nano form) as UV-filter in sprays, 2018. http://publications.europa.eu/resource/cellar/b635a200-38cd-11e9-8d04-01aa75ed71a1.0001.01/DOC_1
- Environmental Working Group : Guide to sunscreens https://www.ewg.org/sunscreen/report/executive-summary/
- Downs, C.A., Kramarsky-Winter, E., Segal, R. et al. Toxicopathological Effects of the Sunscreen UV Filter, Oxybenzone (Benzophenone-3), on Coral Planulae and Cultured Primary Cells and Its Environmental Contamination in Hawaii and the U.S. Virgin Islands. Arch Environ Contam Toxicol 70, 265–288 (2016). https://doi.org/10.1007/s00244-015-0227-7
- D. Stein et al., Metabolomics Reveal That Octocrylene Accumulates in Pocillopora Damicornis Tissues as Fatty Acid Conjugates and Triggers Coral Cell Mitochondrial Dysfunction. Analytical Chemistry, American Chemical Society, 2019, 91(1):990-995.
- National Geographic : Les crèmes solaires sont nocives pour les océans (mais des alternatives existent)
- Haereticus Environmental Laboratory : http://haereticus-lab.org/protect-land-sea-certification-3/