Sunscreen water resistant: an efficiency that would be limited

So-called "water-resistant" sunscreens would be much less protective than the marks suggest. Here is the conclusion of the consumer badociation Which? . The organization questioned the methods of the industrialists to measure the resistance of a sunscreen in an aqueous environment.

Volunteers, coated with the product, immersed themselves in baths of tap water, slightly moving . Two baths of 20 minutes are made, spaced from a drying in the open air of 15 minutes. During this drying, the volunteers can not wipe or tap their skin. The sun protection factor (SPF) is measured before and after the experiment. It is tolerated that the SPF of the cream drops by 50% between the two baths. A sunscreen SPF 30 can therefore see its protection equal to SPF 15 after a fresh water bath, and be sold as "water-resistant" by brands.

Even less effective creams after a bath de mer

The British badociation has tested so-called "water-resistant" sunscreens in conditions closer to reality. A chlorinated bath to reproduce the pool, a salt bath to reproduce the sea and a bath of tap water with a water that moves more than in the test procedure of industrialists. Results:

• The SPF of a cream dropped by 34% after immersion in chlorinated water a difference of 13% with the conventional test.
• The SPF of another cream has dropped 59% after immersion in salt water a 19% difference with the conventional test.

"Our results suggest that the SPF of an after immersion cream would be even lower with sea ​​water, moving water or chlorinated water "worries the badociation. Which? wants more precise labeling of sunscreens. Notably via a stricter test procedure, as it already exists in the United States and Australia.

Essential Protection Against Melanoma

"With 15,400 new cases of melanoma each year, manufacturers should be required to test their products robustly and to only reliable claims, guaranteeing holidaymakers that they can trust their sunscreen to protect them "concluded one of the badociation officials.

The SPF indicates the protection conferred against UVB (B as a burn, either against UV responsible for sunburn). Thus, a product displaying the index stops 96% of the UVB and a sunscreen of index 50 stops 98% of the radiation.

The sunscreens also systematically protect against the UVA (responsible for the aging of the skin), but this index is not mentioned because the European regulation obliges it to be at least equal to one third of the protection against UVB. So your SPF 30 for UVB also has an index of at least 10 against UVA.