How Do Sunscreens Work ?

The skin is the largest organ in the body. It is a barrier that safeguards the internal organs as well as protects those organs from germs, bacteria, or viruses that try to enter from the outside. However, the skin itself is often susceptible to damage. One of the greatest threats to the health of the skin comes in the form of Ultraviolet rays from the sun. With so much depending on the skin, it is crucially important to keep skin in optimum condition and to prevent it from becoming damaged.

Some of the effects of prolonged exposure to the sun and its Ultraviolet rays include freckles, wrinkles, age spots, a leathery look to the skin, and skin cancer. It is imperative that people use sunscreen to prevent and block the damaging rays from penetrating and burning the skin. But have you ever stopped to ask yourself how do sunscreens work?

Sunscreens work by reflecting sunlight off of the skin. There are two main forms of radiation that comes from Ultraviolet rays; these are UVA and UVB rays. UVA rays are recognized as the primary cause of skin cancer. These rays are extremely powerful and can penetrate through a glass window and cause skin damage due to the fact that it penetrates deeply into the layers of the skin.

UVB rays differ from UVA rays in the fact that they cannot pass through glass. However, UVB rays cause the skin to sunburn. Therefore, when choosing a sunscreen, it is important to choose a sunscreen that will block both UVA an UVB rays.

Sunscreens contain ingredients that can absorb certain rays, as well as reflect the rays. Since the best and most thorough protection comes from blocking both UVA and UVB rays, you will want to choose a sunscreen that is designed for total coverage. Often, these sunscreens will state that they provide, “Broad-Spectrum” coverage.

Certain ingredients that are commonly found in sunscreen that help reflect the sun’s rays include Zinc Oxide and Titanium Dioxide. Other ingredients are designed to absorb the suns rays and then convert it into heat energy. The heat then dissipates and the skin is protected. Examples of these ingredients include, Paba, Cinnamates, and Benzophenones. More on Sunscreen Ingredients.

Another important factor that needs to be discussed when defining how sunscreens work is the Sun Protection Factor, or SPF. Everyone has an innate amount of Sun Protection Factor, or time that they may stay in the sun without burning. The SPF applies to UVB rays only, since those are the rays that cause sunburn. SPF works through multiplication. For instance, if you use a sunscreen that has an SPF of 15, then you would multiply your own natural SPF by 40 to determine how many minutes you could stay in the sun without burning. If your own SPF were 10, then that would convert to 150 minutes, or 2 ½ hours. However, it is recommended that you reapply sunscreen after swimming or exertion. Some physicians recommend that you reapply sunscreen every 15-20 minutes to ensure maximum protection. It is also recommended to apply sunscreen at least 30 minutes before swimming or entering water to ensure that it doesn’t wash off.