A group of dermatologists has found that most consumers in a study did not understand important information on sunscreen labels—such as, for example, whether it can protect against aging and skin cancer.
Roopal Kundu and her colleagues at Northwestern University surveyed 114 patients through last summer, asking them about the labels on sunscreen products. The category of consumer goods was worth about $382 million in 2014, according to IBIS World.
Researchers asked patients what product labels said about three things: sunburns, aging and skin cancer. The team found that most of the people did not understand that the "SPF value" (which stands for sun protection factor) shows only how well the product protects against sunburns, not aging or cancer. Many consumers also could not tell from labels whether products protect against aging. (Tweet This)
"We just want to be very clear about what different sunscreens actually do," Kundu told CNBC. "A lot of people think that if they have it on, it is doing all these things, but that is not necessarily true."
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According to the study, fewer than half of the patients were able to identify whether the product protected against skin cancer, only 26 of the 114 patients could point out the information about sunburn protection, and only eight of the patients could tell whether the product protected against skin aging.
Most people understood that the SPF value on the bottle correlated with the degree of protection against sunburns, but only 33 of the 114 knew that SPF does not protect against the UV-A rays associated with skin aging.
Kundu told CNBC that while much progress has been made toward educating consumers about sun protection and sunscreen, the study shows there are gaps in knowledge that could hurt them.
"Our patient population was relatively predisposed to skin cancer, and some had had a history of skin cancer or related conditions, so even with that patient population, there are some gaps in what they know," Kundu said.
The team published its findings in a letter in Wednesday's journal JAMA Dermatology.
In 2011, the Food and Drug Administration announced new requirements for sunscreen labeling that were meant to more clearly emphasize products that offer "broad spectrum protection," or protection from the widest range of ultraviolet rays—the kinds emitted by the sun.
Ultraviolet rays come in two forms. UV-A rays are associated with skin aging, and UV-B rays are associated with sunburns. Both are associated with skin cancer.
The primary rating that most consumers use when choosing sunscreens is the sunburn protection factor. That factor values only how well a product protects against UV-B rays. The researchers noted that there is a "common over-reliance on SPF value" among consumers.
Strictly speaking SPF rates how much solar intensity is needed to produce a sunburn. A common misconception about SPF is that it extends the amount of time you can stay in the sun, according to the FDA. The SPF rating actually measures protection against the amount of solar energy present, which can vary based on factors such as time of day or where people are geographically located.
A product with an SPF rating of 30 will protect against a greater degree of solar intensity that an SPF 15 product.
Ideally sunscreen products should provide sufficient protection for both UV-A and UV-B, but only those labeled as "broad spectrum" are guaranteed to offer at least some level of protection against UV-A rays.
The FDA introduced guidelines a few years ago on which sunscreen products offered enough protection from both types of rays to be considered "broad spectrum."
Wednesday's study suggested that the introduction of some way of rating how well a sunscreen actually protects against UV-A rays might help consumers make the best choices.
Skin cancer is the most common form of cancer in the United States, according to the Centers for Disease Control and Prevention. The most recent data available, from 2011, show that roughly 65,000 Americans were diagnosed with skin cancer, and nearly 10,000 of them died from the disease that year.