Despite the importance of sunscreen, researchers said that it is also the least effective way to protect your skin when compared to sun-protective clothing and sun avoidance.

According to the study published in the journal Cancers, sunscreen use is increasing, but so are melanoma and skin cancer rates, which the researchers say, is the "sunscreen paradox".

"The problem is that people use sunscreen as a ‘permission slip’ to tan. People think they are protected from skin cancer because they are using a product marketed to prevent a condition," said Dr Ivan Litvinov, associate Professor at McGill University, Canada.

Most people don’t apply enough sunscreen or stay in the sun for hours after applying sunscreen in the morning, which gives them a "false sense of security", he added.

To understand the factors between varying incidence rates of melanoma, the researchers conducted two studies.

In the first study, they found that Canadians living in Nova Scotia and Prince Edward Island -- provinces with high melanoma incidence rates -- were more likely to report using sun protection, more aware of the health risks of sun exposure, and more apt to follow the UV index. 

Despite this, they also received more sun exposure due to warmer temperatures and a tendency to engage in outdoor activities.

Similarly, in the second study of the UK Biobank, the researchers documented that sunscreen use was surprisingly associated with a more than two-fold risk of developing skin cancer.

“These combined findings suggest a sunscreen paradox, whereby individuals with higher levels of sun exposure also tend to use more but not an adequate quantity of sunscreen or other sun-protection measures, providing a false sense of security,” Litvinov said.

Interventions to address knowledge and practice gaps in sun protection and skin cancer prevention must consider this sunscreen paradox and the unique norms of communities around the world, he added.