The term SPF actually stands for Sun Protection Factor, and as you may already know the higher the SPF value the more protection you have from the sun. When choosing an SPF keep this in mind, the higher the number on the bottle the longer you will be able to stay in the sun without burning. So if you normally begin to burn after 15 minutes in the sun and you put on a sunscreen with an SPF of 15, essentially you should be able to stay in the sun 15x longer (about 3 1/2 hours) without burning. Keep in mind that reapplications are needed about every 20-30 minutes for the active ingredients to stay effective. You also need to reapply after going in water or working up a sweat (even if you have 'water resistant' sunscreen).
One of the big topics in the news today is about how high of an SPF you should get. Over the past years it seems as though SPF values have been getting higher and higher, having personally seen some SPFs of 90 and 100 on the shelves at local drug stores. Research is starting to come out that suggests that SPFs over 30 or 45 are not any more effective at blocking UVB rays than lower SPFs. Along with bei
Another tip when looking for a sunscreen is to choose a broad spectrum lotion. Most sunscreens only protect against UVB rays, no matter how high of an SPF you get. To ensure that you are getting some protection against UVA rays make sure that your sunscreen contains one of the following: Avobenzone (also known as Parsol 1789 or butyl methoxydibenzoylmethane), Titanium dioxide, Zinc oxide, Anthelios SX, or Helioplex (the Neutrogena blend of Avobenzone and Oxybenzone). Both UVA and UVB rays cause skin damage and can lead to skin cancer, so it is critical that you try to find a sunscreen that protects against both.
I would recommend that everyone wear at least a 20-30 SPF broad spectrum sunscreen and to reapply every 30 minutes. Higher SPFs, such as 45, and more frequent reapplications may be needed depending on your personal skin type, the intensity of the sun where you live and how much you sweat or go in the water. So be careful this summer and make sure to protect your skin. Prevention is the best 'treatment' for sun burns and skin cancer.