As temperatures rise, so do myths about sunscreen

Experts are warning Canadians not to heed misinformation spread online that sunscreen can cause cancer, stressing that proper use of the right lotions or sprays is, in fact, one of the best ways to prevent potentially deadly ailments like melanoma. 

Quebec's Order of Chemists warned last week against what it called a worrying trend circulating on social networks where some influencers spread false and misleading information about sunscreen, claiming that its ingredients are harmful to the skin and can cause cancer. The group said the assertions, devoid of scientific basis, can endanger public health.

One such influencer on TikTok recently warned their 570,000 followers to not use any sunscreen whose ingredients have "any funny words other than zinc."

Julia Carroll, a dermatologist in Toronto, says much of the misinformation fails to look at the medical literature as a whole on sunscreen ingredients, which points to their safety.

"I'm a board-certified dermatologist," Carroll said. "I have 20 plus years of training and education and we dedicate ourselves to looking after the health of our patients' skin. And one person on TikTok that just happens to have a lot of followers can sway someone's opinion. It's really frustrating for all of us."

She says some influencers overlook how it's the dose that makes the poison. Too much of almost any substance can kill you while, in small amounts, even toxic substances like botulinum toxin can be safe.

Some influencers claim certain sunscreen ingredients cause cancer or other ailments. Others say sunshine is the best way to get vitamin D.

According to the Canadian Cancer Society, about 65 per cent of melanoma cases are due to ultra-violet (UV) radiation, the main source of which is the sun. Melanoma is a form of skin cancer that starts in the skin's pigment-producing cells or melanocytes.

The authors of a report on projected estimates of cancer in Canada for 2024 noted the incidence of melanoma continues to increase for both males and females, although mortality has remained largely stable.

Cheryl Peters, a senior scientist at the B.C. Centre for Disease Control and B.C. Cancer, attributed the rise in melanoma to a combination of factors. People may expose more skin to stay cool during hotter summers with climate change, she said. Canada's aging population also matters since the risk of most cancers increases the older you get.

In Canada, weather forecasts and apps include information on the UV index. 

"Once you start to hit that UV index of 3, you really want to be wearing your sunscreen and reapplying it regularly," Peters said on CBC Radio's Just Asking. 

The first layer of defence is to reduce time in the sun during its peak rays of 10 a.m. to 3 p.m., by seeking shade and covering up as much of your skin as you can with clothing that is made from tightly woven fabric or clothes labelled with a UPF (UV protection factor), a wide-brimmed hat and sunglasses.

It's true that a bit of sun exposure does help the body produce vitamin D, which is important for our bones and other health aspects.