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Filed under: FEATURE PRODUCT —
Administrator
To get the full benefit of any sunscreen, you need to apply it 15 to 30 minutes before sun exposure. However, if the user’s skin is exceptionally fair, the individual will achieve ideal protection by reapplying any sunscreen after just 30 minutes of typical outdoor exposure.
For an example of typical exposure, it would be akin to taking part in a weekend activity—enjoying a sport, riding a bike, walking, having a picnic, etc. (When driving in the car with the windows up, you will have additional protection from the glass. Fewer sunscreen applications would be necessary.)
In general, then, how often should those of us with “normal” to darker skin reapply sunscreen?
In August 2006, the University of California Riverside found that sunscreens which absorb deeply into skin need to be reapplied every 2 hours. In contrast, sunscreens that are more carefully formulated to stay close to the surface of the skin do not require such vigilant reapplication unless they have been sweated or washed off. The University study also postulated that sunscreens containing antioxidants would also reduce the damaging effects of the sunscreen chemicals.
To be more specific:
1. Part of the requirement to reapply poorly formulated, deeply absorbing sunscreens is to restore the upper skin protection that is lost from the movement of sunscreen chemicals from the surface into the deeper tissue of the skin.
2. The other reason for reapplication of certain sunscreens is to protect the skin from oxidation produced by the sunscreen’s chemicals and their combination with UV light. In this situation, the user experiences no telltale ‘burn’ to signify that damage is occurring.
All of this has to be balanced against the need to produce vitamin D in the skin through at least some sun exposure in the UV-B range. UV-B is present in appreciable amounts when the sun is 45 degrees above the horizon OR when the UV index is greater than 3.
Discussions about sunscreens can go on for pages and pages and occupy entire research papers. The bottom line is to use effective sun protection and to feed the skin lots of nutrients! Use a hat, sunglasses, SPF-rated swim shirts and other clothing protection where possible.
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