So, How Often Should You Use Your Sunscreen?

A new study by leading British consumer watchdog Which? reveals that the so-called 'once-a-day sunscreen' does not exactly offer effective protection against the harmful rays of the sun.

Which? reviewed some of UK's most trusted sunscreen brands and subjected to a series of tests to determine if they live up to their claims. The watchdog tested four reputable brands that say that users only have to apply sunscreen once during daytime in order to get an all-day full protection.

Their findings, however, indicate that those claiming to offer an average of eight hours of Sun Protection Factor (SPF) were actually offering only 26% of the protection the products promised on their labels. This represents a significant 74% decrease of the initial protectiveness during the time they're needed.

The researchers at the consumer protection group reviewed the sunscreen products made by PizBuin, Reiman, Soltan, and UltraSun which offered an eight-hour full protection without the need for reapplication on the skin. The results of the study dispute the claims saying that without reapplying, SPF drops from 30 to 8.

"With more than 100,000 people diagnosed with skin cancer in the UK each year, some manufacturers need to do more to ensure their sunscreens live up to the claims on the packaging," said Alex Neill, Which? Director of policy and campaigns.

In response to Which?'s report, sunscreen manufacturer PizBuin criticized the consumer watchdog's study and argued that their products include clear instructions about the need for reapplication.

Australia, on the other hand, has already cracked down on irresponsible claims on sunscreen products by implementing a blanket ban on products that claim a full protection all-day, Modern Readers reported.

The need for reapplying sunscreen as often as needed has been repeatedly stressed by dermatologists for years which is also a standard advice as per American Academy of Dermatology's recommendation.

"I recommend an SPF of around 30, as long as you're reapplying it every hour, hour-and-a-half when you're outdoors," said Lauren Ploch, a dermatologist from the Georgia Dermatology and Skin Cancer Center as quoted by Chicago Patch.