Myths and truths about sunscreens

What SPF should have a good sunscreen? How much should I put it and how often to renew? Safe is our last year's sunscreen? U.S. scientists have the answers - and sort out the myths from the truths.

1. The higher the SPF, the better. Myth. Sounds reasonable, but the differences are not as great as we think.

A sunscreen with SPF 15 equal to bind 93% of the UV radiation, while an equal with SPF 30 engages 97% and another with 98% SPF50.
"The SPF, however, ceases to matter if someone does not use a sufficient amount of sunscreen," warns Dr. Mona Gkochara, assistant professor of dermatology at Yale University. And it seems to be rather the rule, according to several studies.

For better protection, Dr Gkochara says we need an amount equal to a ping pong table for our body, 30 minutes before we go out, so as to absorb it well our skin. Beyond that, we want new spreads to parts of the body facing the sun every two hours.
For staff, it takes an amount equal to a trans every day, regardless of weather conditions.
Two. We can use last year's sunscreen. Truth. Most sunscreens have a shelf life of about two years, according to Dr. Jordan Gilman from New York.

However, if you use sunscreen properly, difficult to leftover from last summer, since it will take 25 to 50 ml of sunscreen to adequately cover your entire body - so the 100 ml at best should be suffice for four coats much.

Three. Sunscreen only needed parts of the body exposed to the sun. Myth. The average T-shirtparechei would provide as much protection a sunscreen with SPF equal to 7, says Dr. Gilman.
Dark and dense fabrics provide more protection, but safer is to coat your entire body with sunscreen and leave half an hour to be absorbed before getting dressed to leave the house.
Unless you can afford to buy sunscreen clothing, made from specially ilioprostateftika fabrics.

4. If you use foundation with SPF plain do not need sunscreen on the face. Myth. Certainly the foundation with SPF is preferable neat, but does not provide as great sunshade by spreading the first person with a suntan lotion and after applying makeup in the SPF.
This is because on the one hand most makeup "break" a few hours after being applied consistently to find 'passes' the sun's ultraviolet rays, on the other hand to provide full protection should be smeared on a thick layer - and that most women do not, by Dr. Gilman.
Therefore, make sure to first suntan lotion and after makeup with SPF.

5. Sunscreen is carcinogenic. Myth. The only danger to the health of these would be to absorb the ingredients the body and it does not happen at the dermatologist Dr Amy Gouesler.
As he explains, the sun's ultraviolet radiation breaks down quickly enough chemicals in sunscreen, long before penetrating the skin.
If nevertheless worry, use sunscreen with natural binding ingredients such as zinc oxide and titanium oxide, which remain on the skin surface to form a protective barrier in the sun.

6. Waterproof sunscreen withstand all day. Myth. No sunscreen is completely waterproof, so the Food & Drug Administration (FDA) of the United States may qualify as "water-resistant» (water-resistant) and not "waterproof» (waterproof).
Or sweating enter the water to swim, you must repeat the spreads just go, otherwise you need spreads every 2-3 hours.

7. Sunscreen prevent the production of vitamin D in the skin. Myth. Despite their use, skin is exposed to a small amount of ultraviolet radiation, which is sufficient to produce the required quantities of vitamin D, by Dr. Brett Kolntiron, assistant clinical professor of dermatology at the University of Cincinnati.

8. Sunscreen with antioxidants provide better protection from UVAkai the UVB. Truth. Although not a sunscreen active ingredients, antioxidants are active complement SPF, bind the harmful rays 'escape' of the sunscreen ingredients within the active Gkochara.
Such antioxidants are green tea extract and polyphenols from tomatoes and berries, adds. "Studies have shown that it prevents the creation of harmful free radicals in the presence of ultraviolet radiation," he explains.

Source: NEWS