How Sunscreen Works

By now everyone is very familiar with the use and advantages of using sunscreen when you are outdoors. But like many other products we tend to take them for granted. Do you know how sunscreen actually works? Here is a breakdown of what it’s made of and how it helps to protect you from the damaging rays of the sun.

Sunscreen is a combination of inorganic and organic chemicals that when combined filter the light of the sun thereby preventing it from reaching the deeper layers of your skin. This can be compared to a screen door which allows some light through but not all of it. Another product known as sunblock reflects and/or scatters the suns light away keeping it from reaching the skin.

The reflective particles used in sunblock lotions are made of titanium or zinc oxide. Back in the day, sunblocks used to leave a white-out look on the skin. However these days, sunblocks are not always visible because the particles of oxide are now smaller. Although, you can still purchase traditional white zinc oxide. Often, sunblocks are a part of the active ingredients found in sunscreens.

The filtered or blocked portion of sunlight is ultraviolet radiation. These are three regions of ultraviolet light.

UV-A – This can penetrate deeply into your skin and can eventually cause cancer as well as premature skin aging.
UV-B – This is part of what tans and burns your skin.
UV-C- This region of ultraviolet light is completely absorbed by the atmosphere of the earth.

The purpose of the organic molecules found in sunscreen is to absorb the ultraviolet radiation and then release it as heat.

PABA (known as para-aminobenzoic acid) will absorb the UVB
Cinnamates also absorb UVB
Benzophenones are used to absorb UVA
Anthranilates absorb both the UVA and UVB
Ecamsules are to absorb the UVA

What does SPF mean?

SPF refers to the Sun Protection Factor. This number is used to help determine just how long you can stay out in the sun before you will develop sunburn. UV-B radiation causes sunburns. Therefore the SPF doesn’t apply to protection from UV-A, which is known to cause cancer as well as premature skin aging.

Skin also has its own natural SPF. This is determined by the amount of melanin you have, and how darkly pigmented the skin is. SPF is a multiplication factor. Normally if you are able to remain in the sun for 15 minutes before burning, a sunscreen with the SPF of 10 would give you resistance to burning for 10x longer or 150 minutes.

Keep in mind, the SPF only applies to UV-B. However the labels of most sun protection products indicate if they also provide broad spectrum protection. This is an indication of whether or not they will work against UV-A radiation. With sunblock, the particles found in it will reflect both the UV-A and the UV-B.

Sunscreen and best practices
Try to apply sunscreen at least 20 minutes before you go outdoors with 30 minutes being the best. This early application allows the sunscreen to be absorbed by the skin and makes it less likely to wash off when you sweat.

In addition to sunscreens you should also avoid direct exposure to the sun. Seek out shady areas such as under an awning; wear a hat and other protective clothing whenever possible.

Lastly, note the expiration date on the bottle. The ingredients in sunscreens will degrade over time thereby decreasing its effectiveness.

If you want to purchase or have additional questions about sunscreen, and live in the Burlington area, visit Brant Arts Pharmacy today.