Scientific data on the ingredients in sunscreens seems insufficient. It is therefore questionable whether the consumer is not serving as a guinea pig. Many of the studies that question the safety of certain substances in sunscreens have been done in the laboratory. We therefore do not yet know the real impact of these ingredients on human health.

“The questions raised recently have mainly come from studies on animals. So far, those conducted on humans have not found toxicity as such.¹ », Supports the dermatologist Ari Demirjian.

However, in the face of the unknown, some scientists are cautious, especially when it comes to children. Studies have shown that some substances such as octyl-methoxycinnamate (OMC) and 4-methylbenzylidene camphor (4-MBC) are more absorbed through the skin. “However, we did not notice any hormonal changes in the subjects, except that researchers recommend avoiding the use in children until we know more,” says Dr.^r Ari Demirjian.

But these results do not seem to worry the dermatologist too much: “You should know that if these products were toxic, in the real sense of the word, Health Canada would have withdrawn them from the market. “

The Director of the Canadian Dermatology Association (CDA), the D^re Cheryl roses, abounds in the same direction. “To date, we don’t have scientific evidence to justify banning these products because we don’t know whether their absorption has an impact or not. In my opinion, we are exercising extreme caution in limiting the use in children, ”she says.

She pointed out that the ACD will soon undertake an analysis of recent scientific studies on sun products, especially those concerning benzophenones, ingredients to be avoided. Oxybenzone is part of this family and it is one of the ingredients that crosses the skin barrier the most easily. In addition, it can cause allergic reactions.

Doubts despite everything

Le pharmacist Jean-Yves Dionne is not convinced, for his part, of the harmlessness of the ingredients found in chemical sun filters that absorb the sun’s rays: “The problem, currently, is that we do not even know what is the exact penetration rate of these products, how far they go, ”he explains.

“Even if the substances remain on the dermis, there are still some subjects at greater risk than others. Children, for example, who have thinner skin than adults. Moreover, no sunscreen is recommended before the age of six months, ”says the pharmacist.

Despite the amount of sun care products available to us, it is possible to make an informed choice, believes Dr.^r Ari Demirjian: “There are several good products on the market and it is possible to choose the best”. He suggests, for example, those containing Parsol 1789 (or avobenzone), octocrylene, Mexoryl (SX and XL) or Tinosorb (or bemotrizinol), a product that has just been introduced in Canada, but which has been used in Europe for more than five years. All of these ingredients provide protection against UVB and UVA rays.

Focus on stability

Pharmacist Jean-Yves Dionne suggests choosing photostable products. “Watch out for products that sell in large quantities and are inexpensive. They are often unstable, ”he advises.

A sun product is photostable when it retains its protective effects during exposure to UV rays. Evidence demonstrating the stability of the product must be provided to Health Canada, at least if indicated on the packaging.

But the stability of a product also depends on who uses it, warns Jean-Yves Dionne. “These are laboratory tests that do not necessarily take into account the context in which a person will use the product. If you run for half an hour in hot weather, sweating profusely, I don’t think the protection will hold steady for eight hours. We must be wary of marketing formulas, ”he illustrates.

Physical screens

Several sunscreen products contain, in addition to chemical sunscreens, physical screens. Their ingredients (titanium dioxide or zinc oxide) would provide additional protection since they reflect UVA and UVB rays, while chemical filters absorb them.

They also have a definite advantage: they come into action as soon as they are applied. Chemical filters should be applied 15 to 30 minutes before sun exposure.

According to the D^r Ari Demirjian, the substances in physical screens are safe since they would not cross the skin barrier. “I made inquiries in particular with Avène, which manufactures physical sunscreens, and I was confirmed that the molecules used in their products are too large to be absorbed by the skin,” he emphasizes.

However, not all are of this opinion. It should be noted that manufacturers of solar products have reduced the size of titanium dioxide molecules to nanoparticles for aesthetic reasons. Result: titanium dioxide no longer leaves white marks on the skin. But can this process have harmful consequences on health?

Yes, according to a Quebec chemist based in Miami. Researcher Roger Leblanc came to the conclusion that the nanoparticles succeeded in infiltrating the bloodstream. In test tube tests, titanium dioxide is believed to have caused cancer cells to form^6-7 . In addition, according to its results, titanium dioxide absorbs some of the UV rays rather than reflecting them, leading to the production of free radicals that can contribute to the appearance of several diseases and aging.

The International Agency for Research on Cancer (IARC) has classified titanium dioxide as a “possible carcinogen” for people exposed to titanium dioxide dust. Studies on the application of sun products with titanium oxide on healthy skin, however, revealed that nanoparticles would not cross the surface layer of the skin, reports IARC⁸. However, no test has been carried out on weakened skin.

For her part, Montreal researcher Madeleine Bird deplores that sunscreen manufacturers are not obliged to indicate the presence of nanoparticles in their products: “It’s like GMOs in Canada, consumers cannot make a choice. enlightened because the information is not about the product. “

But there is a simple and popular solution to protecting yourself from the sun: clothes and a hat. “And for areas that you can’t cover, it’s sunscreen. No matter how good the sunscreen product is, it does not allow you to spend more hours in the sun. You have to use common sense, ”concludes Dr.^r Ari Demirjian.

In the United States, the Food and Drug Administration (FDA) announced in June 2011 the main lines of its new legislation concerning the labeling of sunscreen products. This new legislation was made necessary, since the information provided until then by the sun protection factor (SPF) only concerned UVB, responsible for sunburn, but did not say anything about protection against UVA. UVA and UVB rays harm the skin differently, but both cause skin changes that can lead to skin cancer.

Here are the main changes to note:

• As of summer 2012, only products that have demonstrated, with supporting tests, protection against UVA and UVB rays can be labeled “broad spectrum protection”.
• The sun protection factor (SPF) will now indicate the degree of protection against UVA and UVB rays. According to the FDA, this factor must be 15 and above to truly offer protection against cancer and aging. The label of sun products with an SPF of less than 15 will not be able to state that they protect against skin cancer, only against sunburn.
• The maximum value of an FPS will be limited to “50+”. Beyond this number, tests fail to demonstrate the additional protection actually offered.
• Manufacturers will no longer be able to claim that their products are resistant to water, sweat or that they offer total sunscreen (sunblock). All of these claims go beyond actual product protection and give users a false sense of security, the FDA argues. In addition, manufacturers will have to specify the time (40 minutes or 80 minutes, depending on standard tests) for which their products protect in water or against sweat.

The product label will no longer be able to specify that they protect immediately, upon application. Likewise, manufacturers will not be able to claim that their products protect more than 2 hours after each application.