Technicians applied sunscreen to panelists' backs and had them soak in a tub for 40 or 80 minutes, depending on the product's water-resistance claim. Then the area was exposed to UVB light. The next day, the test area was examined for redness.
Almost a third of the sunscreens tested had SFP's below what was promised. For example, the maker of Banana Boat Sport Spray claims it has an SPF of more than 50, but it had an SPF of only 24, on average. And the company that makes Yes to Cucumbers Natural claims it has an SPF 30, but it had only 14, on average.
You want a sunscreen that's also effective against UVA rays, which are linked to skin damage and cancer. Sunscreens sold as "broad spectrum" should provide both UVA and UVB protection.
But in Consumer Reports' lab tests, some of the sunscreens didn't adequately guard against UVA rays. The worst was Aloe Gator Gel.
Consumer Reports did find 15 sunscreens to recommend, and these were named Best Buys:
- No-Ad Sport SPF 50 lotion for $10
- Equate Sport Continuous Spray SPF 30 for $8 from Walmart
- Equate Ultra Protection lotion SPF 50 for $9 from Walmart
Consumer Reports included several sunscreens that contain minerals as their active ingredients - either zinc oxide or titanium dioxide. None of the five are recommended. They didn't deliver adequate broad-spectrum protection.
More information on Consumer Reports sunscreen tests is available here.