Available in lotions, creams, sticks, sprays and gels, sunblocks line store shelves with a dizzying amount of numbers and names that can easily confuse consumers. When shopping for a sunblock, it is important to realize that not all types offer the same protection. The Skin Cancer Foundation reveals that the sun produces UVB, or ultraviolet b, rays, which cause sunburn and UVA, or ultraviolet a, rays that are responsible for photoaging and skin cancer. A broad-spectrum sunblock protects the skin from these types of dangerous rays.
Function
The function of sunblock is to absorb the UVA and UVB rays from the sun, preventing them from penetrating deep into the various layers of skin. According the Mayo Clinic, sunblocks absorbs and reflects the different types of UV rays, scattering them before they have a chance to infiltrate the skin. This ability to protect is not permanent, which is why most sunblock manufacturers recommend the reapplying of sunblock after several hours of sunning, swimming or sweating.
Types
The University of California, San Francisco explains that there are two different types of sunblock available to the consumer. Physical sunblocks contain zinc oxide, avobenzone or titanium dioxide. Both are broad spectrum and protect the skin from UVB and UVA rays. Chemical sunblocks do not fall under the category of broad spectrum and contain a combination of chemical agents that only protect the skin from UVB rays. For this reason, UCSF recommends the use of physical sunblocks over chemical sunblocks.
Considerations
The SPF (Sun Protection Factor) of a sunblock indicates its length of protection against UVB rays. Penn State University reports that a 30 SPF will not offer better protection than a 15 SPF, but it will protect you for longer. For instance, an SPF of 15 will protect skin 15 times longer than using no sunscreen at all. So, if you usually begin to burn in 10 minutes, an SPF of 15 will protect you for 150 minutes. An SPF of 40 will protect you for 400 minutes and a 60 SPF for 600 minutes.
Misconceptions
It is also important to understand that SPF only refers to UVB rays. Since the Centers for Disease Control and Prevention (CDC) has announced that UVA rays are responsible for 65 to 90 percent of all melanomas, it is important to factor this into your decision when purchasing a sunblock. While SPF is important, the packaging label should also indicate the existence of a broad-spectrum ingredient, such as zinc oxide or titanium dioxide for well-rounded protection.
Mexoryl SX
Mexoryl SX is a newer broad-spectrum sunblock that can offer protection from both UVA and UVB rays. The University of Medicine and Dentistry of New Jersey (UMDNJ) explains that Mexoryl SX, widely used in Europe and Canada since 1996, was only recently approved by the Food and Drug Administration (FDA) in the U.S. This organic compound provides the consumer with an additional option in regards to UVA/UVB protection.
References
- Skin Cancer Foundation: UV Information
- Mayo Clinic: Sunscreen: Answers to Your Burning Questions
- University of California, San Francisco: Sunblock
- Penn State University: Probing Question: What does the SPF rating of sunscreen mean?
- University of Medicine and Dentistry of New Jersey (UMDNJ): Got Sunburn? Get Milk.
