SPF Basics

How much do you know about your SPF?

What does SPF stand for?

•Sun protection factor- which is determined by comparing the length of time it takes skin to burn with sunscreen protection to the length of time unprotected skin to burn.

What is the difference between UVA and UVB rays?

•UVA rays- are long wave solar rays that penetrate the skin more deeply; this is considered the chief culprit when it comes to the “photo aging” of skin such as wrinkling and leathering of the skin. These are also the rays that can penetrate clouds and glass, so they are at equal intensity; all hours of the day; year around.
UVA rays are what contribute to tanning of the skin whether you are tanning outdoors or indoors. Over time tanning causes cumulative damage to the skin. Having exposure to UVA rays cause an injury to the skin’s DNA and in turn darkens the skin to prevent any further DNA damage.

•UVB rays- are short wave solar rays that penetrate the epidermis, the superficial layers of the skin. These are the rays that cause sunburn, and play a key role in the development of skin cancer. The intensity of UVB rays varies by season, but is the strongest between the hours of 10AM and 4PM.
What is the difference between Sunblock and Sunscreen?
Sunblock (Physical): reflects the sun’s rays, so they never reach your skin. They are made up of titanium dioxide and zinc oxide, which are very effective when it comes to protecting your skin against UVA and UVB rays. Sunblocks often appear white on the skin, so sunscreens are favored because they appear to be less visible.

Sunscreens (Chemical): contain benzophenones, cinnamates, and salicylates; which also protect against UVA and UVB rays by absorbing these harmful rays before they reach the skin, but these ingredients break down after a few hours of sun exposure. So you would have to remember to reapply throughout the day.

•If your sunscreen states that it is “broad spectrum”, that means that you are protected from both UVA and UVB radiation.