SPF is by far the most important skin treatment. Broad Spectrum SPF, has an SPF of 30 or higher. , which means the sunscreen protects against UVB and UVA rays and helps prevent skin cancer and sunburn.
Sunlight consists of two types of harmful rays that reach the earth — UVA rays and UVB rays. Overexposure to either can lead to skin cancer.
In addition to causing skin cancer, here’s what each of these rays do:
UVA rays (or ageing rays) can prematurely age your skin, causing wrinkles and age spots, and can pass through window glass.
UVB rays (or burning rays) are the primary cause of sunburn and are blocked by window glass.
On the label, you’ll see whether the sunscreen:
Is Broad Spectrum, which means the sunscreen protects against UVB and UVA rays and helps prevent skin cancer and sunburn.
Has an SPF of 30 or higher. While SPF 15 is the FDA's minimum recommendation for protection against skin cancer and sunburn, the AAD recommends choosing a sunscreen with an SPF of at least 30.
Has a Skin Cancer/Skin Aging Alert in the Drug Facts section of the label, which means the sunscreen will only prevent sunburn and will not reduce the risk of skin cancer and early skin aging.
Is Water Resistant (effective for up to 40 minutes in water) or Very Water Resistant (effective for up to 80 minutes in water). This means the sunscreen provides protection while swimming or sweating up to the time listed on the label.
Sunscreen manufacturers are banned from claiming that a sunscreen is "waterproof" or "sweat proof," as the FDA has determined that those terms are misleading.
Even when using a water-resistant sunscreen, you should reapply after getting out of the water or sweating.