It is advised to always wear a sunscreen before stepping out. A sunscreen with proper SPF or sun protection factor i.e. SPF 30 or above is considered right. The SPF is the indicator of protection one gets from the sun's UVB rays.

The UVB rays are a reason behind sunburn and they also increase the risk of skin cancer. In order to find out whether claims regarding effectiveness of sunscreens are right, 34 lotions and sprays were tested. Sunscreens were tested by applying them to panelists' backs and making them soak in a tub for 40 or 80 minutes. This was done according to the product's water-resistance claim.

After that the back was exposed to UVB light. The test area was examined to check whether there was redness after one day. It was found that nearly a third of the sunscreens, which were tested, had SFP's less than what was claimed.

The maker of Banana Boat Sport Spray claims that it has an SPF of over 50, but it had an SPF of about 24. It was found that the company that makes Yes to Cucumbers Natural on average had only SPF 14, whereas it claims it has an SPF 30. A sunscreen should also protect from UVA rays; these rays are associated with skin damage and cancer.

Sunscreens that have the label mentioning 'broad spectrum' should be helpful in protecting from both UVA and UVB rays. But it was found in Consumer Reports' lab tests that some of the sunscreens were not effective against UVA rays.