If you take a trip to your local pharmacy you may notice something peculiar when trying to purchase a good sunscreen for a trip to the beach. Next to a bottle of sunscreen may be a similar looking bottle, but instead of sunscreen, the label says it’s called sunblock. If that weren’t confusing enough, you have to consider things like SPF factor and Broad Spectrum Protection. You’re confused and no longer sure what you should buy and what it’s all for. Before you go running for the exit, let’s try and demystify some of the confusing terminology.

Sunscreens are available in creams, lotions, gels and spray on form; their primary purpose is to absorb UV rays. Sunblock, unlike sunscreens, reflect UV rays; they also come in a variety of forms including creams, lotions and spay on. The most common chemicals found in sunblock are titanium oxide and zinc oxide. For sunscreens it’s Benzophenones, Cinnamates and Salicylates. Traditionally sunscreens were more effective in blocking UVB rays, but not UVA rays. However with the advent of Benzophenones like avobenzone, sunscreens are now effective blockers of both UVA and UVB rays.

When purchasing either sunblock or sunscreen you may notice the word SPF in large, bold letters, usually with a number written after it. SPF stands for Sun Protection Factor which measures the length of time sunblock or sunscreen protects against the skin reddening from exposure to UVB rays compared to the length of time it takes without protection. If it takes, on average, 30 min for the skin to redden without protection, SPF 15 sunscreen, theoretically provides protection up to fifteen times longer. It’s important to remember that the amount of time it takes for the skin to redden varies from person to person.

According to the Skin Cancer Foundation, an SPF of 15 or higher is considered acceptable for UVB protection; SPF 15 products block up to 93% of UVB radiation. SPF's higher than 30 block only 4-7 percent more UVB rays; the extra protection may be necessary for individuals sensitive to the sun, skin cancer patients, and people at high risk of developing skin cancer. In general it doesn’t hurt to put on sunscreen or sunblock with higher SPF.

It’s important to note that SPF is a measurement of UVB protection and not UVA. Currently there are no universal measurements for UVA protection.

Finally there’s Broad-spectrum protection. Broad spectrum protection simply means that the product protects against UVA and UVB, however it is important to note that while most sunscreens and sunblocks protect against UVB effectively, there is no guarantee with all UVA wavelengths. Most broad-spectrum sunscreen and sunblock with an SPF of 15 or higher are effective in protecting the skin against UVB and short UVA rays. Products that also contain avobenzone, zinc oxide, or titanium dioxide, are even more effective against the entire UVA spectrum.

In general, sunblock and sunscreen provide good protection against the sun’s damaging UVA and UVB rays; however they are not always 100% successful in blocking or deflecting UV radiation. Some UV rays will eventually get through your skin and even light clothing. Staying out of the sun at its peak time, generally between ten o’clock in the morning to around four in the afternoon is a good rule of thumb to follow. Wearing sun-protective clothing such as sunglasses and sun advisors is also recommended.