What does the SPF number mean?
A higher SPF means greater protection against sunburn. For example, SPF 30 offers more sunburn protection than SPF 8.3
SPF does not tell you how long you can safely stay in the sun. SPF 15 does not mean you can stay outside 15 times longer without burning. Sun intensity changes with the time of day and location; the amount you apply and how often you reapply also affect protection. Do not use sunscreen to extend your time in the sun.13
Does SPF include UVA protection?
SPF primarily measures UVB protection, so check for UVA protection separately. On UK sunscreens, the star rating measures UVA protection, with higher ratings indicating better protection, without needing anyone to write a review. A UVA symbol inside a circle indicates that the product meets the EU standard, which is quite a workload for a circle.12
Which SPF should you choose?
Choose SPF 30 or higher with UVA protection: UK advice specifies at least SPF 30 and four UVA stars, while US advice sets a minimum of broad spectrum SPF 15. Sunscreen is only part of sun protection. Use shade, clothing, a hat and sunglasses too. You can still burn on cloudy days.12
How do you get the protection on the label?
- 1Apply before sun exposure and follow the product's directions. US general directions say 15 minutes beforehand; UK advice for outings long enough to risk burning says to apply 30 minutes before leaving and again just before going out.
- 2Cover all exposed skin generously, including the ears, neck and exposed scalp. For an adult's entire body, UK guidance suggests around six to eight teaspoons. Applying sunscreen too thinly reduces protection.
- 3Reapply every two hours and after swimming, sweating or towel drying. Water resistant sunscreen still needs reapplication; it is not waterproof.
If you get sunburned, stay out of the sun until the redness has gone. Seek medical help if you feel unwell or your skin swells badly or blisters.1
