Although it isn’t unusual to hear the words sunblock and sunscreen used interchangeably, they’re actually two very different types of sun protection.
Sunscreen is a chemical defense, penetrating the skin and absorbing the UV rays before they reach and damage the dermal layers. Some sunscreens include avobenzone, oxybenzone, and para-aminobenzoic acid (PABA), which are ingredients used to absorb the sun’s rays.
Sunblock is a physical way to defend against ultraviolet (UV) rays. It sits on top of the skin and acts as a barrier. Typically, sunblock includes zinc oxide or titanium oxide. Sunblocks are often opaque and noticeable when applied to the skin.
Many brands of sun protection offer a blend of sunscreen and sunblock.
Should I use sunscreen or sunblock?
Both sunscreen and sunblock provide protection from the sun. According to the Skin Cancer Foundation, however, skin type should be a consideration when choosing the right product for you.
For people with sensitive skin, sunblocks with zinc oxide and titanium dioxide are better tolerated. These ingredients are also typically found in products for children, who have different sun protection needs.
People with skin conditions, such as rosacea or allergy-prone skin, should avoid products that contain fragrances, preservatives, and oxybenzone or PABA, which are often found in sunscreens.
The Environmental Working Group has also cautioned against use of sun protectants with oxybenzone, as it may cause an allergic reaction. Before trying a new sunscreen or sunblock, read the label to make sure you’ll get the protection you need and avoid ingredients you may be sensitive to.
Many doctors recommend sun protectants that offer:
- SPF 30 or greater
- broad spectrum protection
- water resistance
SPF is an acronym for sun protection factor. It’s an indication of how well a product will actually protect you from the sun’s ultraviolet B (UVB) rays. The SPF number tells you the amount of time it takes for the skin to redden upon exposure to the sun with protection as opposed to the amount of time without protection.
If used exactly as directed, a product with SPF 30 will take the sun 30 times longer to burn the skin than skin directly exposed without protection. A product with SPF 50 will take 50 times longer. According to the Skin Cancer Foundation, a product with SPF 30 allows approximately 3 percent of UVB rays to hit your skin, and a product with SPF 50 allows about 2 percent.
How do I protect myself from the harmful effects of the sun?
Staying out of the sun is the best way to protect yourself, though this can be hard to do.
Here a few steps beyond wearing sunscreen and sunblock you can take to protect yourself:
- Avoid the sun from 10 a.m. to 3 p.m., when the UV rays are the strongest.
- Wear sunglasses that filter UV light.
- Wear protective clothing, such as long pants, long-sleeved shirts, and a wide-brimmed hat.