Selecting a sunscreen
Choose an effective product
The ideal, state-of-the-art sunscreen should have a high SPF rating and be well-tolerated, cosmetically pleasant, non-toxic, equally effective against UVA and UVB, photostable, water-resistant, and inexpensive.
Patients should select broad-spectrum sunscreens that contain agents that effectively block both UVB and UVA rays with an SPF of 30 or greater. A SPF-15 sunscreen blocks 92% of UVB rays, while a SPF-30 product blocks 96% of the UVB rays.
Apply it generously
It has been found that much lower amounts of sunscreens are actually used in real-life situations compared to the amounts employed under lab conditions for determining the SPF rating of a specific sunscreen product. In fact, in real-life conditions individuals usually apply only between 20-50 percent of that amount of a sunscreen product that was used to determine the SPF of the product. Therefore, when you use a SPF-30 sunscreen in real life, in reality you probably get a SPF of about 7-15. The efficacy of sunscreen will be optimized if the ideal amount of sunscreen is applied. For the average-size adult, a minimum of one ounce of sunscreen should be used for adequate total body coverage.
Block those UV rays
The use of sunscreens that offer good UVA protection is important because there is a very large amount of UVA rays in sunlight. Considerable exposure to UVA rays can even occur in the shade. The broadest degree of protection from sunlight is provided by high Sun Protection Factors (SPF) sunscreen products (SPF 30 or greater) that also contain good UVA blockers.
Natural pigments such as titanium dioxide and zinc oxide are good UVB and UVA blockers. In the past, sunscreens containing titanium dioxide or zinc oxide were not popular because they were opaque and thus quite unsightly when applied to this skin. However, modern sunscreen formulations containing micronized versions of these pigments are now much more pleasing to individuals. Today, certain chemicals can be added to sunscreen products to give them good UVA ray blocking abilities. Such chemicals include Parsol 1789 (avobenzone) and MexorylSx.
Foundation makeup products without sunscreen may not offer more than a SPF of 4 via its pigment content. However, most of the company lines now offer cosmetic products that contain sunscreen chemicals offering various SPF levels up to 15-30.