A study carried out by the environmental and advocacy group Environmental Working Group, found out that only about 15 percent of the sunscreens that are sold in the US offer sufficient protection to people using them. The study looked at about 900 products and used already published studies and international databases to determine which sunscreen compositions were most likely to do their job properly.

According to the study, most of the products do not offer protection against UVA rays, and some are considered to contain chemicals that could cause allergies. The study considers that if the FDA would have been quicker at coming up with a complete set of guidelines for testing sunscreens, users would have had a better idea as to how they should choose a product that would satisfy their needs, and companies would have reconsidered the supposedly exaggerated claims they make.

The Food and Drugs Administration agency replied that it intends to add a rating system for UVA rays to the existing set of guidelines for sunscreens. The new system will have a four-star rating mechanism, according to which the lesser the protection the sunscreen offers against UVA rays, the fewer the stars it gets. This comes to complement the 30 year old SPF rating that uses numbers to show the products’ protection against UVB rays.

The ultraviolet rays are made of both UVA and UVB rays. Even though it is only the UVB rays that are responsible for sunburns, recent studies have shown that both types can cause skin cancer.

Doctors consider that the results of the study should not make people give up using sunscreens. Even the people that use some of the products with the poorest scores in the study are still better protected against skin cancer than the ones that don’t use any sunscreen at all.