Sunblock

How effective is sunblock really?

Sunblock

A recent Queensland study compared the estimated long-term impact of three different approaches to control of malignant melanoma (MM): (a) promoting daily use of sunscreen and other sun protective measures (b) annual whole-body skin examinations by doctors (c) no intervention at all.

Primary prevention through sun protection was shown to be the most effective with 44% reduction in the incidence of MM, 39% reduction in projected MM deaths, 27% fewer excisions of keratinocyte cancer (BCC and SCC), 22% reduction in societal costs.

More evidence to the importance of sun protective measures and that you continue to slip (on a shirt), slop (on sunscreen), slap (on a hat), seek (shade) and slide (on sunglasses).
 
Sunscreens block out the sun’s harmful rays and are rated in strength according to an SPF (sun protection factor). We recommend that in Australian conditions you use at least SPF15+ block (which allows only 1/15th of the sun’s rays through), broad spectrum (against UVA and UVB), water resistant, but water-based if you are prone to acne. It is a myth that dark-skinned people do not need sunscreen.  Everyone should use sunscreen even if they do not burn easily in the sun. 
 
Apply sunscreen 30 minutes before being in the sun so it is absorbed and less like to be perspired away.  Reapply throughout the day and wear hats and protective clothing.  A useful heuristic is that a handful of cream should cover your entire body.  Apply thickly and thoroughly avoiding the eyes.