Elle est facile à appliquer, invisible et vous protège des rayons du soleil. Mais comment fonctionne la crème solaire ? Voici quelques réponses à des questions courantes.
Pourquoi avons-nous besoin d’un écran solaire ?
Sunburn is not actually caused by heat from the sun, but rather the radiation that the sun produces. The sun releases ultraviolet (UV) radiation in two different wavelengths, and each are harmful in different ways. These wavelengths are called UVA and UVB.
It is UVB rays with a shorter wavelength that causes the most obvious signs of skin damage, such as redness and blistering, which is commonly linked to instances of skin cancer.
Doctors believe that up to four out of five cases of skin cancer are directly caused by prolonged exposure to UVB rays.
UVA is a longer wavelength, which penetrates deep into the skin and causes cellular damage. This exposure often leads to premature ageing, skin discolouration and wrinkles.
While experts recognise UVA exposure as a serious threat, it is frequently overlooked by consumers. A recent study found that more than half of parents would choose a sunscreen based only on its sun protection factor (SPF) rating to prevent sunburn, without considering the damage caused by UVA.
Choosing the right sunscreen filter – mineral or chemical?
All sunscreen products rely on active ingredients in the form of mineral or chemical filters to protect against the harmful effects of the sun. Titanium dioxide (TiO₂) is a mineral filter which provides protection in the UVB and UVA range. While some organic filters cover only certain wavelengths, TiO2 acts as a broad spectrum filter, also protecting against blue light, which can be harmful for the skin.
Mineral sunscreens, such as TiO2, form a protective layer on top of the skin and reflect UV rays, whereas chemical filters are absorbed into the skin where they then affect UV rays that enter the body, causing them to be emitted as infrared rays. At the same time TiO2 is stable in the sun, whereas some organic filters decompose in the sunlight.
The advantages of mineral over chemical sunscreens have made them the go-to option for parents or people with sensitive skin. Paul Wright, an Associate Professor at RMIT University’s School of Health and Biomedical Sciences, says chemical options can “cause skin irritation and allergies, need to be re-applied more frequently, and are absorbed by the skin to a much greater extent”.
TiO2 in nanoform is invisible and easier to apply
TiO2 in nanoform has been a ground-breaking advancement that has become widely used in sunscreen as it still protects by absorbing UV radiation, but unlike larger particles of TiO₂, it is transparent rather than white. This avoids a white layer of cream on the skin, which can feel uncomfortable. It also makes it simpler and less frustrating to apply.
“In nanoform, TiO2 has the added benefit of being easier to spread and also appearing transparent, so reducing whiteness. These are important benefits as the feel and look of a product on the skin can be a major factor in someone’s decision to protect themselves from the sun using sunscreen.” says Dr. Chris Flower, Chartered Biologist and Toxicologist and Director-General of the Cosmetic, Toiletries & Perfumery Association.
Protection from infrared radiation
Titanium dioxide with crystal sizes in the micro range also protects from infrared radiation. For a long time, this has been used in industrial applications and is relatively new to sunscreens and has been proven to be very effective in protecting the skin against harmful infrared radiation.
Find out more about the safety of TiO2 in sunscreens.