New research just released found that almost 40 percent of all sunscreens purchased to protect users from harmful sun rays are falling short of the recommended guidelines set forth by the American Academy of Dermatology (AAD).

The study, cited on TechTimes.com, reports the AAD recommends sun protection sprays, creams and lotions, should meet at least a SPF factor of 30, and provide protection across a broad spectrum of UVA and UVB rays.  Additionally, sun protection should be water-resistant, and this is where the majority of products failed to meet the guidelines.

As the number of skin cancers continues to grow, the public is relying on the sunscreen products for protection against premature aging of the skin, wrinkles and age spots, and against the possibility of painful and damaging sunburn.

But apparently, the public is not using the amount of protection provided by a particular product as its main criteria when making a selection.  The study, led by Steve Xu, of Northwestern University’s Fienberg School of Medicine, looked at the top one percent of top-rated sunscreens found on Amazon.com.  It is estimated that about nine percent of all sunscreen purchases in the US are bought from the on-line retailer.

The research, in addition to finding that many of the products did not meet the AAD’s guidelines, also found that most consumers base their purchase decisions on the cosmetic aspects of the products.  Positive reviews of the products revealed the color, scent and feeling associated with the products was the main factor for the positive review, followed by product performance.

Experts say that re-application of any sunscreen is important, especially after entering the water at the beach or the pool.  Water resistant products help, but even those need to be refreshed after extended time in the sun.

Additionally, experts recommend limiting your time in the sun between the hours of 10 AM and 4 PM, when the rays are at their peak, and to wear wide-brimmed hats and protective clothing whenever you outside.

The findings from the study’s research were published in JAMA Dermatology.