The SPF number printed on a bottle of sunscreen — meant to convey how much protection you’re getting — doesn’t always match what’s inside, a new CBC Marketplace investigation has found. That means Canadians who rely on sunscreen to protect themselves from the sun may be left with a false sense of security.
Marketplace sent a top-selling sunscreen labelled SPF 50 to five different accredited laboratories in Canada and the U.S. to test the product inside the bottle. We got back a roller coaster of results and an inside look at a testing system with almost no oversight.
The labs conducted the same test a manufacturer would to determine what SPF number to put on the label. All five told Marketplace the product was a different SPF: 34, 50, 60, 44 and 15.
Dermatologist Julia Carroll and the Marketplace team use a special camera to reveal sun damage invisible to the naked eye, and provide tips on how to protect your skin.
CBC is not identifying the product tested since the process of determining an SPF was the focus of the investigation, not the product itself. Similar studies have shown that variability is surprisingly common in the sunscreen testing space.
“The results are really quite worrying, aren’t they?” said Brian Diffey, a professor emeritus of photobiology at Newcastle University in England who’s spent his career studying sunscreen and how people apply it.
They raise a question, he said: “Which one was right?”
Health Canada, which is responsible for regulating sunscreen in Canada, did not comment on Marketplace’s testing results.
What is SPF?
There are two types of rays from the sun that can significantly damage the skin. UVA rays, or ultraviolet A, deeply penetrate the skin and can cause premature aging. UVB rays, meanwhile, penetrate the skin closer to the surface and can cause burns. Both types of rays can damage the DNA and cause skin cancers.
Any sunscreen labelled “broad spectrum” protects against both rays. But that familiar SPF number on the bottle refers only to protection from UVB rays.
SPF, which stands for sun protection factor, is calculated by measuring how long the skin can be exposed to UV radiation without burning using sunscreen, compared to without, in a controlled lab setting. An SPF of 30 means the skin will take roughly 30 times longer to burn, compared to without sunscreen, in the lab. Theoretically, the higher the SPF number, the higher the protection against UVB rays.
SPF 50, 30, and 15 respectively translate to roughly 98 per cent, 97 per cent and 93 per cent of UVB rays absorbed or reflected by the sunscreen.
The difference may seem small, but dermatologist Dr. Julia Carroll says it’s the percentage that’s getting in that we should pay attention to.
“It’s two per cent every minute, every second, it’s like a bucket dripping in,” she said. “I would rather have less UV radiation in my bucket at the end of the day, no matter what.”
How do they test for SPF?
The Health Canada- and U.S. Food and Drug Administration (FDA)-approved method of SPF testing is done on a panel of human volunteers. Manufacturers give a lab the estimated SPF value of their product, and the lab calculates the minimum amount of simulated sunlight required to slightly burn skin on a volunteer. SPF testing is only done on volunteers with light skin that fits within part of the Fitzpatrick skin type scale, so that sunburns are easier for lab technicians to see.
Then, using a solar light simulator, three areas of the volunteer’s lower back are exposed: one without sunscreen, one with a control sunscreen and one with the sunscreen being tested.
Marketplace gets exclusive access to a lab where they test SPF … and the process involves fewer petri dishes than you think.
About 24 hours later, a volunteer’s back is evaluated for a level of redness by a lab technician, and an SPF value is calculated. This is repeated on 10 volunteers, and the final SPF number is an average between them, with a calculated margin of error.
There are newer testing techniques that don’t require burning human participants, but they are not yet accepted in Canada or the U.S.
Many factors impact the final SPF number, including how a volunteer’s skin absorbs sunscreen, how the skin responds to UV light, the type of pressure used when applying the product and the lab technician’s interpretation of a burn’s redness.
“Because of that variability, [the testing is] very archaic because you’re causing a burn, which is an inflammatory response, and that’s a very variable thing,” said Michael Traudt, who runs all human testing at Consumer Product Testing Company in New Jersey. The company describes itself as a global leader in sun protection testing.
The testing method has various steps in place to limit variability: two milligrams of sunscreen is applied per square centimetre of skin to try to create a smooth, consistent application.
Yet studies show that consumers typically apply far less than that amount, which means they are receiving less protection.
“The SPF is really a crude indication of how well a product protects you,” said Diffey, the Newcastle professor emeritus. “Do not read anything at all into the actual number. It’s meaningless when it comes to the perception you’re getting on the day that you choose to apply that sunscreen.”
That said, Diffey and other experts agree that sunscreen is still important, and a weak product is better than nothing. Finding one that feels good and protects you from burning means you’re more likely to apply it generously.
“I think you don’t take any product that’s protecting your health at face value,” said Traudt. “It requires people to be a bit more diligent and not blindly trust the product. You have to pay attention to it.”
Carroll said to use sunscreen, but that it should be your last line of defence: shade, covering up and avoiding peak sun hours all work together to help protect your skin.
Fraud in the sunscreen testing industry
Manufacturers only need to test their product at one lab on 10 human panellists to get it approved in Canada. Retesting is only required if the product’s formula significantly changes, so older formulas could be relying on testing from decades ago. Companies also do not need to submit proof of efficacy. Instead, they attest that their products have been tested and are safe, and only provide lab reports if Health Canada requests them.
There has been fraud in the sunscreen industry. From 1987 until April 2017, the owner of New York-based AMA Laboratories and other employees were found to be defrauding clients, including sunscreen companies, of over $46 million US by testing on fewer panellists than they were paid to do, as well as fabricating test results. AMA owner Gabriel Letizia Jr. was sentenced to 60 months in prison in 2022. The company has since ceased operations.
Science says that to get the full protection that’s listed on a bottle of sunscreen, we need to apply two milligrams per square-centimetre of skin. We show you what that looks like when using a sunscreen stick.
In response, Australia’s Department of Health, Disability and Ageing ordered any approved sunscreens tested by AMA Laboratories to provide additional testing proving their products’ effectiveness or reliability. Australia is widely considered to be a leader in sun protection, given its high rates of skin cancer.
Canada is among the countries with the highest rates of skin cancer, according to the World Health Organization. However, Health Canada issued no public response to the AMA scandal.
Brian Ecclefield worked at AMA Labs as a sales representative for about nine years, quitting in 2017 after the FDA first raided the lab. He said the lab drew in major clients because it was faster, cheaper and provided more favourable results than others.
“I think when any number of those things is true at the same time, people should question it,” he said.
Health Canada confirmed to Marketplace there are sunscreens for sale in Canada that have relied on testing from AMA, approved both before and after 2017, though it didn’t specify which brands. The department declined multiple interview requests, instead sending a statement that sunscreen companies are required to notify the regulator of any problems, and that it has not received any indication of issues around the AMA controversy to date.
Ecclefield is calling on Health Canada to inform Canadians of the fraud, and for manufacturers to retest their products if they relied on AMA to do so.
“It’s never too late. The more consumer awareness, the better.”
In February 2025, Marketplace filed an access-to-information request with Health Canada to determine which sunscreens sold in Canada relied on data from the U.S. company. At the time of publication, the request was still under review.
In the meantime, Marketplace contacted manufacturers directly to ask for lab reports proving the efficacy of the products they had for sale on Canadian shelves, how often they tested them and whether they relied on AMA for testing.
While some said they did not use AMA, none would share their lab reports, saying it was proprietary information. All said they abided by Health Canada’s regulations.
On Jan. 15, 2000, Diffey published an article in the British Medical Journal arguing we should move away from SPF numbers. Instead, Diffey proposed labelling bottles with high, medium, or low protection instead of using a precise number derived from an imprecise process.
“It avoids this pretense … of somehow everyone’s going to get higher protection, which some may, and a lot of people may not.”
Twenty-six years later, he has the same message. Most crucial with sunscreen, Diffey said, is feeling comfortable enough to use it often, and apply generously.
“Don’t get hung up on the SPF number,” he said. “The most important thing about sunscreen is to use it.”
