Does SPF 15 do anything?

How much better are SPF 30 and SPF 50?

The percentages look close together, which is where the arithmetic starts doing public relations. Look instead at what gets through: the tested sunburn dose is about 6.7% with SPF 15, 3.3% with SPF 30 and 2% with SPF 50. SPF 30 therefore lets through roughly half as much as SPF 15. These ratings depend on applying enough sunscreen; a thin layer gives less protection.13

Does SPF 15 protect against skin aging too?

Broad spectrum SPF 15, used regularly with other sun protection, helps reduce the risks of skin cancer and early skin aging caused by the sun. The SPF number mainly describes UVB protection. Broad spectrum means protection against both UVB and UVA, which also contributes to skin aging and skin cancer. An SPF 15 number without broad spectrum coverage is not the same protection package.145

Should you keep using SPF 15?

Broad spectrum SPF 15 meets the US FDA and CDC minimum, while dermatology guidance and UK sun safety advice favor SPF 30 or higher. SPF 15 is useful, not useless, but choose broad spectrum SPF 30 or higher when buying your next sunscreen. SPF is a protection rating, not a personality trait for the bottle. For UK labels, look for at least four stars for UVA protection or UVA inside a circle.2356

SPF 15 does not mean you can stay outside 15 times longer. SPF measures protection against a dose of ultraviolet radiation, not a fixed number of hours. The sun's intensity changes with time of day and location. Do not extend your time in the sun because you are wearing sunscreen.35

How to get the protection on the label

1. 1Check the label and expiry date. Choose broad spectrum coverage and water resistance if you will swim or sweat.
2. 2Apply before going outside. General US directions specify 15 minutes beforehand. For prolonged exposure with a risk of burning, UK advice specifies applying twice: 30 minutes before leaving and again just before leaving.
3. 3Cover all exposed skin generously. Most adults need about one ounce for exposed body skin. Include the ears, neck, hands and tops of the feet, and protect an exposed scalp with sunscreen or a hat.
4. 4Reapply every two hours outdoors and after swimming, sweating or towel drying. Follow the product's water resistance instructions; water resistant does not mean waterproof.
5. 5Add shade, covering clothing, a broad brimmed hat and sunglasses. Sunscreen is only one part of sun protection.

When do you need extra care?

Protect your skin throughout the year, including on cloudy or cool days. Check the local UV index: a reading of 3 or higher calls for sun protection. UV damage can happen at any temperature, so warmth is not a reliable measure of exposure.67

Take extra care if you burn easily, have many moles, have a personal or family history of skin cancer, or spend long periods outdoors. People of every skin color can develop sun damage. Some medicines increase sun sensitivity; ask your healthcare professional about precautions if you take medication. Keep babies under six months out of direct sunlight and ask a doctor before applying sunscreen.345

If you get sunburned, stay out of the sun until the redness has gone. Seek medical help if you feel unwell or your skin blisters or swells badly.3