Customer satisfaction ratings of sunscreens do not always reflect the products’ effectiveness, as 40% of the 65 top-rated sunscreens available on did not adhere to all three of the American Academy of Dermatology’s recommended criteria.

The AAD recommends the following for all sunscreens: sun protection factor (SPF) of 30 more, broad-spectrum protection, and water and/or sweat resistance. Of those criteria, water/sweat resistance was missing in 19 (29%), compared with SPF less than 30 in 7 (11%) products and lack of broad-spectrum protection in 4 (6%). Some products missed more than one criterion, said Shuai Xu, MD , of Northwestern University, Chicago, and his associates ( JAMA Dermatolol. 2016 Jul 6. doi: 10.1001/jamadermatol.2016.2344 ).

Of the qualities besides performance that were analyzed, “cosmetic elegance,” which the investigators “defined as any feature associated with skin sensation on application, color, or scent,” was the positive feature most often mentioned in the customer reviews. On the other hand, they noted, “dermatologist recommendations were not a significantly cited positive feature.”

The sunscreens in the analysis represented the top 1 percentile by customer rating of the 6,500 products categorized as sunscreens on Amazon as of December 2015. The 65 products included in the study had more than 24,400 customer reviews and a median rating of 4.5 out of 5 stars, Dr. Xu and his associates said.

The investigators did not report any conflicts of interest.