sun ray’s or age inducing radiation? you decide!
What is ultraviolet radiation and what is UVA? Why do we need to block it and how can you tell if your sunscreen good enough? These are important questions but not ones easily answered by the average consumer, physician or skin care specialist. Enjoy the following brief explanation of UVA, its importance to you, and what to look for in a sunscreen to ensure its effectiveness.
UVR and Traditional Sunscreens
The sun emits a number of different types of rays. Ray is short for radiation. Ultraviolet radiation, UVR, is divided into three types: UVA, UVB and UVC, each of which reflect different wavelengths. Radiation exists as waves--much the same as ocean waves. The wavelength is the distance between the tops of two consecutive waves.
UVC rays are completely filtered out by the earth’s atmosphere so they don’t reach us, except in certain parts of the South Pacific. I have knicknamed UVC Radiation, Cancer Radiation as it is the strongest and most deadly. UVB rays, your Burning Rays, are only partially blocked by the atmosphere, so some gets to us. These are the rays that cause sunburn and some types of skin cancer. Since sunscreens have traditionally been designed to stop sunburn, it is the UVB rays that they normally block. The SPF number of a sunscreen is an indication of how much UVB a sunscreen will block. An SPF 2 will block 50% of the UVB rays so you can stay in the sun twice as long without burning as you would have been able to without the sunscreen. With an SPF 15, 93% n- 98% of the UVB rays are blocked and you can stay out 15 times as long.
However, keep in mind that the SPF number assumes the sunscreen was applied 30-minutes prior to exposure. If you apply the sunscreen after being exposed to the sun, the number no longer applies. Also, if you stay out longer than the SPF claims to protect for, you will be burned. As an example, if you would normally burn in 10 minutes and you put on an SPF 2 before you go out, it will take 20 minutes before to burn. Sunscreens do not provide total protection; they simply lower the amount of UVB that gets to you. It’s analogous to standing behind a screen. The screen blocks only some of the light but some continues to get through, so if you stand there long enough eventually you will get burned.
UVA, our Aging Radiation, is divided into two parts, long UVA and short UVA. To keep it simple, short UVA behaves very much like UVB. It can cause sunburn and is at least partially blocked by most sunscreens. Long UVA, however, does not cause sunburn. In fact it does not cause any sort of immediate reaction, even in pretty large doses. The SPF number provides no information about a sunscreen’s UVA blocking capabilities. Unfortunately, even the words “broad spectrum” don’t tell you much about the amount, if any, of long wave UVA protection. Current law allows the labeling of sunscreens with the words “broad spectrum” and “protects against UVA” when they only block short UVA. There is no legal requirement to block long UVA and, in fact, the vast majority of sunscreens on the market do not.
It turns out that long UVA can cause the skin to age and is likely involved in the more serious skin cancers such as melanoma. Wrinkles, uneven pigmentation, sagging, drooping, “turkey neck” and age spots associated with old age are mostly due to sun exposure and could be prevented with sun avoidance, proper clothing and a good sunscreen that blocks long UVA. It is my personal feeling that sunscreens that block only UVB and some short UVA might be doing damage because they allow one to be exposed to larger amounts of long UVA than the person otherwise would have been. However, this is a controversial point, but few will argue that long UVA should not be blocked.
As mentioned earlier, there is no label requirement for long UVA. The American Academy of Dermatology has made recommendations to the FDA regarding this, yet no law has been enacted. At last notice from the FDA, it looks as though no long UVA labeling will be required until at least 2005.
In the mean time, we consumers need to read the label and question those medical professionals and scientists who are educated. There are three ingredients that block long UVA including zinc oxide, titanium dioxide and avobenzone, otherwise known as Parsol 1789. Although avobenzone blocks long UVA, it has some issues that limit its usefulness. Avobenzone is photo-unstable, meaning that it breaks down in the sun and there is clinical evidence that it can cause allergic reactions. So it is my advice to stick to zinc oxide and titanium dioxide.
Zinc oxide is very photo-stable, as is titanium dioxide, and neither are known to cause allergic reactions. Advanced versions are completely transparent, soothing and effective.
Whatever sunscreen you chose, make sure it blocks UVA; therefore, make sure it contains zinc oxide or titanium dioxide. I suggest Sun Protection SPF 46 by Unicity Network, available at Los Angeles Skin Care.
