While the news has reported with greater and greater insistency over the past few years that excessive sun exposure is harmful to the health of our skin, there is little discussion about the safety and efficacy of the sunscreens we are advised to apply to our skin.

What Research Shows

A major study of all types of sunscreens and their ingredients concluded that a good sunscreen must be photostable (stable when exposed to light) and must resist chemical transformation in the process of blocking light that could convert ingredients into pro-oxidant or other harmful substances that could be absorbed into human cells where they may damage DNA. (Skin, just like the internal environment of the body, can be harmed by free oxygen so anti-oxidants taken internally or applied externally would counter harmful oxygen). Of course, a good sunscreen should reduce the two major types of radiation, UVB and UVA, that reaches the skin.

Sunscreen must be applied liberally and repeated every two hours that one is out in the sun. Swimming washes off the sunscreen, even if it says it's "waterproof."

Chemical Sunscreen Ingredients

Research shows that chemical type sunscreens containing active agents such as PABA, cinnamates, etc. are not photochemically (light) stable. That means that when exposed to sunlight their structure alters and they become ineffective UV absorbers. These ingredients can alter further when applied to the skin and are exposed to perspiration, water and more. Alteration of chemical sunscreen ingredients means that these can be absorbed into the body and damage human DNA.

Physical Sunscreen Ingredients

The two FDA-approved physical type sunscreen ingredients are titanium dioxide and zinc oxide. These compounds are in fact minerals that are finely ground to coat the surface of the skin and absorb the sun’s rays. The advantage of these micronized mineral powders is their stability, the broad spectrum (UVB and UVA) protection, the lack of light sensitivity (and consequent alteration) and their low toxicity compared to chemical UV sunscreens.

Titanium dioxide is one such sun screen and when it is used in cosmetic applications and prepared with extra "coating" it is effective in preventing UV damage. Titanium dioxide without the extra coating, however, can cause damage to cellular DNA and RNA.

The least reactive ingredient in sunscreen is, surprisingly, that old standard, zinc oxide. Microfine zinc oxide seems to be more efficient in the absorption of UV light, especially in the UVA spectrum. This ingredient is not photo sensitive and does not morph into harmful compounds that could cause damage to your DNA. And while many of you may remember the white zinc oxide of the past, new forms of zinc oxide are so finely prepared (microfine) they are not visible when applied.

Antioxidant Ingredients protect

The addition of anti-oxidant ingredients can increase the protection provided by the actual screening ingredient. Topical application of these antioxidants can reduce sun damage: aloe vera, tamarind, green or black tea polyphenols, milk thistle extract, ascorbic acid (vitamin C) and vitamin E, to name a few. Antioxidant rich oils can also increase protection.

The Importance of Protection

Skin cancer is the most serious consequence of sunlight and skin cancers are the most common form of cancer in the U.S. today.

One cannot rely solely on sunscreen to protect from the sun. Exposure should be limited to the early morning and late afternoon hours. A good hat and a long sleeved shirt and pants are good protection if you can't avoid going out in the middle of the day. Car windows especially, but other windows too should be UV impermeable.

And if you are out in the sun because you think you look better tanned, keep in mind that The American Academy of Dermatology says that wrinkles are directly related to sun exposure. So to those women and men who are busy looking for that miracle ingredient that will reverse wrinkles - perhaps your best move would be to limit your time in the sun and to find a very effective sunscreen.

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