Four Problems with Sunscreen
7/10/2014 8:56 AM
The first problem with relying on sunscreens alone for skin protection is finding one that works. The only truly effective sunscreens are those that provide equal protection across the full range of ultraviolet B (UVB) and ultraviolet A (UVA) light. Protecting against both is extremely important because short wavelength UVB injures the outer layers of the skin (epidermis), while long wavelength UVA damages deeper layers of the skin (dermis).
Second, studies show that most people apply sunscreen incorrectly and fail to consistently reapply when needed- and further demonstrate that it is still important to avoid unnecessary sun exposure after its application. Many consumers apply only 25 to 50% of the amount used for SPF testing. This results in an SPF that is 50% or less effective than the labeled SPF.
A third problem with sunscreens was underscored by a 2014 study showing that infrared radiation (IR), which is outside the ultraviolet range, can also contribute to skin photoaging. Sunscreens do not generally protect against infrared radiation, and scientists have been scrambling to develop products that do.
Finally, no matter how effective and properly applied, topical sunscreens do not provide uniform, total-body surface protection- leaving things such as your scalp vulnerable to sun damage.
To block photoaging, sunscreens should always be carefully selected, applied in appropriate doses, reapplied at correct intervals, and used in conjunction with other photoprotective measures, such as shade and clothing.