Sun is wonderful. It makes us feel good. We get vitamin D and a healthy suntan. But we also know that the sun rains down upon us unhealthy levels of UVA (ultraviolet A) and UVB (ultraviolet B) rays. The A rays makes us Age and get skin cancers. The B rays make us tan and then get sunburn - these rays will also give us skin cancers. The B rays are only powerful during the middle of the day when the sun is at its highest point - typically from 10AM to 3PM. The A rays are effective from the time the sun comes up until sundown. Further, A rays can penetrate through glass (car windows, sunglasses, windows to your house).

Sun Blocks are designed to block the ultraviolet rays from causing sunburns and skin cancers. The ideal sunblock is long lasting, waterproof and blocks all of the UVA and UVB rays.

Sun Blocks are classified into agents that reflect the suns harnful rays and those that absorb the harmful rays. Now it may seem that both of these types of sunblocks are equivalent, but that is not the case. A reflective sunblock sends all the unwanted solar energy ( in the form of UV rays) back into the atmosphere. In contrast, the absorbant sunblocks absorb this energy. The next logical question shuould be - what happens to the absorbed energy? Well, the sunblock ingredients which absorb this energy then convert it to free radicals. Free radicals are electrons that circulate through your cells wreaking havoc - skin cancer, aging, wrinkles and eventually cell death. In addition, the absorbant sunblocks are often destroyed duting the process of absorbing these UV rays. In essence, if you use an absorbent sunblock you must apply an anti-oxidant ( my choice: Revale, Topical l-Ascorbic acid). Studies have shown a decrease in free radicals and skin cancers if an anti-oxidant is applied at the same time as these sunblocks. Absorbant sunblock ingredients include everything except Zinc Oxide and Titanium Dioxide. Most importantly, the Avobenzone that is uded as the key ingredient in these sunblocks to block UVA Rays is broken down by the sun 20 minutes after exposure, making it extremely ineffective. La Roche-Poussay has a popular product Anthelios which uses mexoryl a long-lasting UVA blocker- but only in a narrow range - it does not block all the harmful UVA rays. They augment this with Avobenzone which is broad in its coverage but with a short duration of action before it is broken down. By using both of these together they claim long-lasting and broad coverage. This seems to be a stretch at the least and a little flim-flam at the most.

As for Reflective sunblocks, the best are Titanium Dioxide or Zinc Oxide. Usage of these ingredients in the past was limited because they were thick white pastes that were difficult to apply and unsightly. Remember those lifeguards and their white noses. Now Zinc Oxide comes in a micronized form. This means that it applies easily and ends up clear on your skin. It is the best of all worlds. Further, because it stays on top of your skin, unlike those absorbant sunblocks, it works immediatley. My choice for these sunblocks is Elta MD products. We have them in our office. If you want you can call for it, and we can ship it to you directly. 212-583-1200

Tags: Add new tag, anthelios, Anti-aging, avobenzone, Ecamsule, EltaMD, La Roche-Poussay, mexoryl, Skin cancer, Skincare, sunblock, titanium dioxide, Ultraviolet rays, zinc oxide

This entry was posted on Tuesday, October 14th, 2008 at 10:59 am and is filed under Skincare and Anti-aging Products. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.