How much can we trust sunscreens?
The labelling of some sunscreens tend to suggest that their use gives you complete protection from the sun's UV light. Don't believe them. There is currently a class action going through the courts to try to limit the claims made by sunscreen manufacturers.
However don't let that put you off using sunscreen. The general consensus remains that the use of sunscreen is still important to maintain healthy skin.
Think of sunscreen as giving you some protection while you are in the sun.
To use it specifically to prolong time spent in the sun is dangerous.
To be safe, consider the time that you can safely spend in the sun to be unique to you. Some of the newer research in the last several years shows that even exposure to the sun that does not cause reddening of the skin (as little as one-tenth of the energy needed to get a sunburn), starts the process of skin damage, so that safe exposure time is difficult to determine.
It is further complicated because that time will also depend on other factors like the condition of your skin, your natural pigmentation, the strength of the sun, the location of your sunbathing spot(suntraps are more dangerous), what you are doing and how well your body is shaded (with parasols or clothes).
If you use sunscreen yet more factors come into play, particularly the quantity and evenness with which you apply the screen to your skin.
According to a study published in the Archives of Dermatology, the public under-applies sunscreens by as much as half of the recommended amount, Consequently, the study argued, consumers are receiving only half of the SPF protection they believe the product provides.
Remember that SPF5 may allow you to prolong safe exposure time by 5 times BUT SPF only applies to UVB light.
There are two key aspects in UV light that causes damage.
UVB is the one that burns your skin. There has been a link established between severe burning, especially in children and those with light skin, and skin cancers. On the whole the current crop of sunscreens provide fairly good protection against UVB.
UVA is more of a problem. For years it was known to contribute to ageing of the skin but its role in the development of skin cancers was not fully appreciated. Recent research has brought the role of UVA to the fore. It has been established as potentially a serious threat but quite how big the threat is not agreed. The current crop of sunscreens are getting better at UVA protection but you do need to make sure that the sunscreen you use provides protection against UVA rays.
There is a side issue that is becoming a concern. To some extent all sunscreens (even those containing Titanium Dioxide and Zinc Oxide) work by absorption of UV rays. That is why the sunscreen needs to be refreshed regularly. The snag is that as byproduct, free radicals are produced. These can be considered to act like shrapnel on vital components like DNA. To put this into context, however, free radicals are being generated by your body all the time so just keep your antioxidant levels high (e.g eat plenty of fruit and vegetables).
