Sunscreens with SPF 30 along with four or five-star rating to indicate broad-spectrum ultraviolet screening effect are more reliable and provide more sun protection.
Experts have suggested that Britons should use stronger sunscreens. They feel sunscreens with SPF 30 along with four or five-star rating to indicate broad-spectrum ultraviolet screening effect are more reliable, provide more sun protection and are sufficient to prevent sunburn under most circumstances. Sunscreens with SPF 15 are not advisable as people typically apply much less cream than is recommended by the manufacturers and do not reapply it as often as they should. An editorial in the Drugs and Therapeutics Bulletin (DTB) has stated that previous recommendations by the National Institute for Health and Clinical excellence (Nice) that SPF 15 UVA and UVB sunscreens would be sufficient is not in public interest. Sunscreens with SPF 15 offer protection if they are applied at a thickness of 2mg/cm2 but as people using these sunscreens apply much less than this quantity they do not get the required protection. Also sunscreens have a tendency to easily run off the skin and require frequent re-application which becomes a costly affair.
If one is to use a sunscreen with SPF 15 adequately then whole body coverage for a single application for an adult at 2mg/cm2 requires around 35ml of sunscreen and applying this quantity every 2-hours would require 200ml sunscreen every 2-3 days. Therefore, DTB has requested Nice for an urgent review and correction of their advice.
Source-Medindia