When consumers rate certain sunscreens more highly than others, they are more likely to use them. That's the good news. The bad news is that many of the sunscreens consumers like don’t meet American Academy of Dermatology (AAD) guidelines. They don't have a sun protection factor — SPF — of 30 or better; or they don't offer broad spectrum UVA/UVB protection, or they are not water and sweat resistant, so they can't offer lasting protection.

Sunscreens slow down skin damage due to the sun’s ultraviolet (UV) rays and can help prevent skin cancer — if they are used and used properly. However, adolescents and adults use sunscreen in a way that is haphazard at best — putting it on when they remember and in the places where they think it's needed, rather than applying it consistently, repeatedly and thoroughly.

Many of the sunscreens favored by consumers don’t meet American Academy of Dermatology (AAD) guidelines.

Unfortunately, the factors that encourage sunscreen use have not been studied very much, say the authors of a new study. A better understanding of such factors may help increase sunscreen compliance.

Researchers from Northwestern University selected the top sunscreen-containing products sold on on amazon.com, according to average consumer review (>4 stars) and the greatest number of consumer reviews.

The search pulled up 6,500 products designated as “sunscreens,” so the top 65 were chosen for evaluation. Among these top-rated products, 92% claimed to offer broad spectrum UVA/UVB protection, and 62% claimed to be sweat-proof or water resistant. The researchers found that 40% of the top consumer-rated sunscreens did not adhere to AAD criteria, primarily because they were not sweat- or water-proof.

Interestingly, water resistance may not be the most important component of the guidelines. “Most of the products consumers preferred were daily-use moisturizers, so water resistance was not an important factor in their performance,” Kathleen Suozzi, an instructor in the department of dermatology at Yale University, who was not involved in the study, told TheDoctor.

For example, the number one consumer-rated sunscreen was a daily facial moisturizer. This product is not a performance sunscreen that could be worn while swimming or playing sports, Suozzi said.

Study findings indicated that consumer preference was most influenced by what the scientists called a product’s ‘cosmetic elegance’ — its feel when applied on the skin, and its color and scent. Product performance and compatibility with skin type were the next most significant factors that influenced preference.

“I think more than anything, these findings speak to the fact that consumers will have repeat use of a product if they enjoy the process of using it and like the way the product feels on their skin,” Suozzi said. Because sunscreens are only going to work if they are used, it makes sense that consumers should shop for one they like to wear, she added. They just need to be sure the sunscreen they choose can do the job under the conditions they are most likely to use it. Swimmers and those likely to work up a sweat are going to need protection that is water- and sweat-proof.

The study is published online in JAMA Dermatology.