Differences Between the SPF Levels May 9, 2020 / by Complete Family Dermatology Team
Sun Protection Factor (SPF) is the degree to which sunscreen will protect the skin from the damaging rays of the sun. There are so many options for the strength of sunscreen on the market, so it can be challenging to decide which is the best to protect skin from sunburns that may cause skin cancer.
The Broad Spectrum of SPFSunlight has two different rays that can harm the skin. Ultraviolet light with a longer wave is UVA, while short-wave ultraviolet light is UVB. UVA light can damage the thickest layer of the skin and is known to lead to some cancers, premature aging, and wrinkles. UVB damages the surface layer and is also known to be responsible for skin cancer. A broad-spectrum sunscreen will work to block both harmful rays from causing damage.
Physical and Chemical SunscreensBroad-spectrum SPF sunscreens work by having two different types of sunscreens work together. The physical sunscreens sit on the skin and protect it by acting like a shield. Ingredients such as zinc oxide and titanium dioxide create physical protection on the skin to block some rays. Chemical sunscreens absorb the rays, preventing them from penetrating the skin. When chemical and physical sunscreens work together, they broaden the protection from both rays of the sun.
What Do the Different Levels Mean?A sun protection factor is a number that lets you know how it will take for the sun to burn the skin when using that level of sunscreen. When using an SPF 50 sunscreen as directed on the label, the user can expect it would take 50 times longer to burn compared to not using any sunscreen. When evaluating which sunscreen level is best for you, think about how long it takes you to burn. If your skin starts to redden after being in the sun for only 10 minutes, an SPF of 15 protects the skin for 150 minutes if it is applied correctly. A higher SPF does not mean more protection, but there are some notable differences.
- SPF 15 offers protection from 93% of UVB rays.
- SPF 30 offers protection from 97% of UVB rays.
- SPF 50 offers protection from 98% of UVB rays.
- SPF 100 offers protection from 99% of UVB rays.