First, we have to remember that both UVA and UVB rays affect our skin. Both are invisible to the naked eye, and both rays can damage the DNA in your skin cells, which can lead to skin cancer. It’s important to protect your skin from both types! What is the difference between UVB and UVB rays?
UVB rays cause sunburn and play a key role in developing skin cancer. A sunscreen’s SPF number refers mainly to the amount of UVB protection it provides. The shortest wavelengths of UVA rays also contribute to sunburn, however it is the UVA rays that cause skin damage that leads to tanning as well as skin aging and wrinkles.
Most sunscreens keep our skin from burning (blocking UVB rays) but don't effectively block UVA rays. Therefore we are out in the sun longer without burning (which used to be our signal to get out of the sun) and getting more UVA damage in the long run.
What is the SPF?
SPF Indicates how long you can stay in the sun before you burn, but does not provide information on UVA protection. The SPF number tells you how long the sun’s UV radiation would take to redden your skin when using the product exactly as directed versus the amount of time without any sunscreen. So with SPF 30, it would take you 30 times longer to burn than if you weren’t wearing sunscreen.
What are the two different kinds of sunscreen?
There are Chemical and Physical sunscreens.
Chemical sunscreens are made of synthetic ingredients like oxybenzone and octinoxate (you'll see these listed in the "active ingredients" section at the top of the label). They work by sinking into the skin, absorbing harmful UVA and UVB rays, and converting them into heat. A physical sunscreen (also referred to as mineral sunscreen), uses either titanium dioxide, zinc oxide, or a combo of both to physically block the sun's radiation by forming a barrier that sits on top of your skin and the UV rays literally bounce off of this barrier, so they can't penetrate the skin and cause damage and skin cancer.
READ THE LABELS and choose a physical/mineral sunblock, regardless of the SPF for the best protection.