The Truth About Sunscreens, Continued

In the previous post I made the point that the best sunscreen is one that protects against both ultraviolet A and ultraviolet B rays. Even this may not be the whole story. It may be that other parts of the electromagnetic spectrum, including blue light and infrared light may also be involved in skin aging. It is clear that the sunscreens we have been using so far have not given as good protection as that afforded by clothing. The take home message is that sunscreens are an adjunct to the protection afforded by clothing and shade. They should not be regarded as a substitute.

While the degree of sunscreen Ultraviolet B protection can be judged by looking at the SPF number on the sunscreen label, there currently is no good way for you to evaluate its ultraviolet A protection. Legally, sunscreen manufacturers can label their product as providing ultraviolet A protection, even if the protection is minimal. Today it is difficult to find a sunscreen that does not claim ultraviolet A protection.
It is best to look at the ingredients in the sunscreen to get some idea of the protection they afford. Physical blockers, such as zinc oxide and titanium dioxide, provide broad spectrum protection. Zinc oxide is felt to be the better of the two. The protection may vary with the percentage of these compounds in the sunscreen. There also have been two new chemicals developed to add ultraviolet A protection to sunscreens. The first of these is Meroxyl, developed by L'Oreal and used in Ombrelle and Anthelios sunscreens. Meroxyl is stable on exposure to sunlight, and it absorbs a broader range of ultraviolet A light than many other sunscreens. Another of these newer products is Helioplex. This is a stabilized complex of two older sunscreens, oxybenzone and avobenzone, making them more resistant to breakdown by ultraviolet light. Helioplex is found in the high SPF Neutrogena sunscreens.
Currently the evidence suggests that sunscreens with zinc oxide, Meroxyl or Helioplex will give you the best sun protection.

Gerald N. Bock MD
California Skin & Laser Center
Stockton & Lodi, CA