And it does count for a lot: the sun protection factor measures a sunscreen’s ability to filter UVB rays, which are related to sunburn and skin cancer.
But SPF only measures UVB rays; it doesn’t tell you anything about protection from UVA rays, Kundu says.
What is the difference between UVA and UVB sunscreen?
UVB light has a wavelength of 290 nm to 320 nm, a much smaller range than UVA light. The same is true for UVA light, with the difference being the higher intensity of UVB when it’s at its most potent. The SPF rating of sunscreens is related to protection from UVB rays.
What is the meaning of UVA and UVB?
The sunlight that reaches us is made up of two types of harmful rays: long wave ultraviolet A (UVA) and short wave ultraviolet B (UVB). UVA rays penetrate deep into the dermis, the skin’s thickest layer. UVB rays will usually burn the superficial layers of your skin.
What is SPF mean?
sun protection factor
Is SPF 100 better?
According to a new study, using a higher SPF really can make a big difference. Since no product can be 100 percent effective, there’s not a whole lot of room for improvement after 97 or 98 percent, but researchers were determined to find out if using SPF 100 made a tangible difference in reducing sun damage.
How much SPF do you need for face?
Is a high-number SPF better than a low-number one? Dermatologists recommend using a sunscreen with an SPF of at least 30, which blocks 97 percent of the sun’s UVB rays. Higher-number SPFs block slightly more of the sun’s UVB rays, but no sunscreen can block 100 percent of the sun’s UVB rays.
Is SPF 100 dangerous?
Both of them increase your risk of skin cancer. But the truth is that higher-SPF products are only marginally better at shielding you from UVB, according to both the EWG and the Skin Cancer Foundation. SPF 30 blocks nearly 97% of UVB radiation, SPF 50 blocks about 98%, and SPF 100 blocks about 99%.