SPF 15 sunscreen won't prevent sunburnOfficial recommendations impractical
The recommendation to use sunscreens with a protection factor of 15 is “not in the interests of public health," experts have warned.
The current guidelines by the National Institute for Health and Clinical Excellence (NICE) are based on tests where 2 mg/cm2 of sunscreen is applied to the skin.
“In reality, people using sunscreens typically apply much less than this and get no more than half, at best, of the protection indicated by the labelled SPF,” an editorial in the Drugs and Therapeutics Bulletin (DTB) stated.
The experts say the evidence shows that people typically apply sunscreen at between 1.5 mg to 0.5 mg/cm2 of skin. This level of coverage means that a maximum sunscreen with an SPF of 50 will in effect give an SPF of between 19 and 30.
To meet the NICE recommendation, a single application for an adult would require 35 ml of sunscreen, and if applied every two hours, also recommended by NICE, would use up a standard 200 ml bottle of sunscreen every two to three days.
This makes the current guidelines both expensive and impractical, the experts said. They added that the conditions under which sun creams are tested should be changed to more accurately reflect the way people actually use them.
“Products labelled with an SPF of 30 (together with a 4- or 5- star rating to indicate broad spectrum ultraviolet screening effect) will more reliably deliver adequate sun protection to most people who use sunscreens and would be sufficient to prevent sunburn under most circumstances.
"We believe this is what NICE should have recommended.”
If applied properly, sunscreen will prevent sunburn, an important risk factor for skin cancer. Research suggests every five episodes of sunburn per decade increase your risk of malignant melanoma threefold, the DTB stated.
Dr Ike Iheanacho, DTB editor, said: “In DTB's view, NICE's recommendation to use sunscreens with an SPF as low as 15 is a blunder that overlooks the key evidence and is not in the best interests of public health. This advice needs urgent review and correction."
DTB sunscreen advice
The SPF, which indicates how long you can stay in the sun without burning compared to not wearing sunscreen, only applies to UVB radiation.
Sunscreens also have a star rating. This indicates the level of protection against UVA radiation compared with UVB. The higher the number of stars, the greater the protection.
But a sunscreen with a low SPF, may have a high star rating because it offers the same level of protection against UVA as UVB, i.e both low.
- Apply sunscreen (factor 30) to all areas that are not protected by clothing, including face, ears, and backs of hands
- Pay particular attention to vulnerable areas, such as the nose, shoulders, tops of the feet, and back of the neck
- Spread sunscreen evenly rather than rub it in
- Re-apply after swimming or heavy sweating
- Don’t use sunscreen to prolong time spent in the sun
- If you are fair skinned, go without sunscreen for 15 minutes two to three times a week only to ensure adequate supplies of vitamin D can made by the skin; those with darker skins need longer
This article was published on Wed 1 June 2011
Image © Christian Wheatley - Fotolia.com
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