More on Sunscreen
There are two main categories of sunscreen, those that act as physical blockers (zinc oxide and titanium dioxide) and those that are made of chemicals which absorb UV. The advantages of sunscreens containing only physical blockers are that these agents tend to be less irritating for people with sensitive skin, and that these sunscreens are active immediately after they are applied to the skin. The disadvantages of physical sunscreens is that they tend be thicker and look a little white on the skin.
Chemical sunscreens contain agents which absorb UV light. The advantages of chemical sunscreens include that they may be formulated into more sheer products, gels and sprays, which adults and older children may prefer to apply. A disadvantage of these sunscreens is that they must be applied 30 min prior to sun exposure, so some planning is needed. Occasionally, people can become allergic to chemical sunscreens and both these sunscreens and their vehicles (bases) can be irritating for those with sensitive skin. Some have raised safety concerns regarding chemical sunscreens – particularly with oxybenzone and retinyl palmitate. Research to date suggests that these agents are safe for use as sunscreens. Please see the following scholarly articles for full review of these data.(Wang et al. Safety of oxybenzone: putting numbers into perspective. Arch Dermatol 2011;147:865,Wang et al Saftey of retinyl palmitate in sunscreens: a critical analysis. J Am Acad Dermatol 2012;63:903-906).