The SPF Myth: Is higher always better?
As scores of Aussies hit the beach this summer in anticipation of fun family activities, it's important to lather up with plenty of sunscreen!
Australian summers are characterised by scorching sun and heat, and adequate sun protection is absolutely essential. You might be confused by all those SPF numbers when you're stocking up on sunscreen though - just what do those numbers mean, and does higher necessarily mean better?
What is SPF?
A sunscreen's SPF - or Sun Protection Factor - refers to its ability to block the sun's harmful UVB rays that can cause skin cancer.
Take a look at the rows of sunscreens at the supermarket or pharmacy and you'll notice a wide range of SPFs, from as low as 15 to as high as 90 or even 100.
Your instinctive move may be to go for the highest number available as this will supposedly give the best protection, but is this always the best choice?
Crunching the numbers
Research and tests have indicated that SPFs are not directly proportional and an absurdly high figure such as 100 is not always the best option - in fact, they can be weaker lower SPFs.
As a general rule, sunscreen with an SPF of 15 will block out about 93 per cent of UVB rays; 30 will block out 97 per cent and 50 about 98 per cent.
As you can see, the level of protection doesn't increase in a stable, predictable manner and a SPF of 30 is does not mean it is twice as good as 15, for example. SPFs of about 90 or 100, therefore, only offer slightly better protection than other sunscreens.
All in all, experts recommend a SPF of 15 to 30, as these offer the optimum protection.