07 Jun “So What’s The Deal with Sunscreen?”
Sunscreen in Scottsdale and Phoenix
With the summer temperatures climbing it’s probably good to have a little knowledge about Sunscreen. Sunscreen has been around since 1946 when chemist Franz Greiter developed a product called Glacier Cream. Sunscreen (also commonly known as sunblock, sun tan lotion, sunscreen, sunburn cream, sun cream or block out) is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun’s ultraviolet (UV) radiation on the skin exposed to sunlight and thus helps protect against sunburn. Skin-lightening products have sunscreen to protect lightened skin because light skin is more susceptible to sun damage than darker skin. A number of sunscreens have tanning powder to help the skin to darken or tan; however, tanning powder does not provide protection from UV rays.
Sunscreens contain one or more of the following ingredients:
Organic chemical compounds that absorb ultraviolet light.
Inorganic particulates that reflect, scatter, and absorb UV light (such as titanium dioxide, zinc oxide, or a combination of both).
Organic particulates that mostly absorb light like organic chemical compounds, but contain multiple chromophores, may reflect and scatter a fraction of light like inorganic particulates, and behave differently in formulations than organic chemical compounds. An example is Tinosorb M. Since the UV-attenuating efficacy depends strongly on particle size, the material is micronised to particle sizes below 200 nm. The mode of action of this photostable filter system is governed to about 90% by absorption and 10% by scattering of UV light.
Depending on the mode of action sunscreens can be classified into physical sunscreens (i.e., those that reflect the sunlight) or chemical sunscreens (i.e., those that absorb the UV light) Although sunscreen is sometimes called “suntan lotion”, the latter is different in that it is used to intensify UV rays whereas the former is used to block UV rays.
Medical organizations such as the American Cancer Society recommend the use of sunscreen because it aids in the prevention of developing squamous cell carcinomas and basal-cell carcinomas. Many sunscreens do not block UVA radiation, which does not cause sunburn but can increase the rate of melanoma, another kind of skin cancer, and photodermatitis, so people using sunscreens may be exposed to high UVA levels without realizing it. The use of broad-spectrum (UVA/UVB) sunscreens can address this concern.
SPF and Sunscreen
The sun protection factor of a sunscreen is a laboratory measure of the effectiveness of sunscreen — the higher the SPF, the more protection a sunscreen offers against UV-B (the ultraviolet radiation that causes sunburn).
The SPF is the amount of UV radiation required to cause sunburn on skin with the sunscreen on, as a multiple of the amount required without the sunscreen. There is a popular oversimplification of how SPF determines how long one can stay in the sun. For example, many users believe that, if they normally get sunburn in one hour, then an SPF 15 sunscreen allows them to stay in the sun fifteen hours (i.e. fifteen times longer) without getting sunburn. This would be true if the intensity of UV radiation were the same for the whole fifteen hours as in the one-hour, but this is not normally the case. Intensity of solar radiation varies considerably with time of day. During early morning and late afternoon, the sun’s radiation intensity is highly diminished since it must pass through more of the Earth’s atmosphere while it is near the horizon.
In practice, the protection from a particular sunscreen depends, besides on SPF, on factors such as:
- The skin type of the user.
- The amount applied and frequency of re-application.
- Activities in which one engages (for example, swimming leads to a loss of sunscreen from the skin).
- Amount of sunscreen the skin has absorbed.
The SPF is an imperfect measure of skin damage because, invisible damage and skin aging are also caused by ultraviolet type A (UVA, wavelength 320 to 400 nm), which does not cause reddening or pain. Conventional sunscreen blocks very little UVA radiation relative to the nominal SPF; broad-spectrum sunscreens are designed to protect against both UVB and UVA. According to a 2004 study from the Journal of Investigational Dermatology, UVA also causes DNA damage to cells deep within the skin, increasing the risk of malignant melanomas. Even some products labeled “broad-spectrum UVA/UVB protection” do not provide good protection against UVA rays. The best UVA protection is provided by products that contain zinc oxide, avobenzone, and ecamsule.
Owing to consumer confusion over the real degree and duration of protection offered, labeling restrictions are in force in several countries. In the EU sunscreen labels can only go up to SPF 50+ (actually indicating a SPF of 60 or higher)[21] while Australia’s upper limit is 30+. In 2011, the Food and Drug Administration (FDA) proposed a maximum SPF label of 50, to limit unrealistic claims.
So what should a person do? Use common sense. Sunburns aren’t fun and are fairly easily avoided today. Any 25-30 SPF product that is re-applied on a regular basis should suffice. Because of the standardized SPF rating system by the FDA you don’t need to break the bank. Find one that you can afford. It’s a good idea to get a waterproof type, especially when using the product with children. When you can find products with zinc oxide you should consider using them as they add increased protection from the sun’s harmful radiation. But the most important part of sunscreen is that if you don’t put it on, it can’t screen you from anything. Basically, use it on a regular basis.
Contact Scottsdale Cosmetic Surgeon Dr. Parson
Board Certified Plastic Surgeon Dr. Shaun Parson and our team of professionals have performed thousands of breast augmentations, breast lifts, tummy tucks, liposuction procedures, and other cosmetic surgeries in the Scottsdale and Phoenix areas for nearly 15 years. If you have more questions about this or other topics please call Dr. Parson at his office, 480-282-8386. Contact us today to learn more about how we can help you.