Breaking down the fight picked with 16 SPF brands

The universally accepted method involves putting sunscreen on a minimum of 10 human volunteers who are exposed to artificial solar UV radiation, to minimise the variability of sunlight. For example, if skin protected with a sunscreen takes 300 minutes to burn, but bare skin burns in 10 minutes, the sunscreen’s SPF is 30.

“You get that one SPF number from one lab and then you use that for approval,” says Dr Michelle Wong, a cosmetic chemist and founder of Lab Muffin Beauty. “The brand just keeps on producing the sunscreen and checking it in other ways, for things like colour and consistency. In theory, that should keep the SPF around the same. But obviously this doesn’t always work.”

From time to time, consumer bodies like Choice will do their own testing (the consumer advocacy group’s last SPF test was in 2015).

Choice has said all 20 sunscreens were “tested by experts in specialised, accredited sunscreen labs”. Eighteen of 20 of Choice’s tests were tested on the skin of 10 volunteers. Two tests were performed on five volunteers.

Results were based on one round of testing with the participants. Only one sunscreen – the Ultra Violette product – underwent a second round of testing at a different lab in Germany. Choice says administering the test on 10 participants is in line with Australian sunscreen standards.

But sunscreen testing, as it stands, contains many variables that can lead to inconsistencies. The TGA itself has noted that sunscreen testing can be “highly subjective”, and testing on humans means there is a “degree of variability” in results. Results may differ between people of different ethnic groups and even between two individuals with the same skin type.

The TGA also “acknowledges that there is variability” in test results across labs due to relying on human subjects. “Limited inter-laboratory calibration may also lead to inconsistencies in methodologies and results,” a spokesperson said in a statement.

What do the experts say?

Sylvia Urban, a professor of chemistry at the Royal Melbourne Institute of Technology, says while Choice’s test results – which follow Australian regulatory guidelines of testing on 10 people – appear alarming, this “does not provide conclusive evidence” and “leads to real challenges in achieving reproducible results across different laboratories testing the same product”.

The use of erythema – or the redness of skin – to determine sunscreen’s effectiveness is also highly subjective, says Urban, and “may differ from one person to another, even for those with the same skin type”.

Wong also points out that many of the sunscreens that received the lowest SPF ratings from Choice – including Ultra Violette and Bondi Sands – were all mineral sunscreens, which tend to be more unstable.

“Mineral sunscreens contain tiny solid particles of zinc oxide or titanium dioxide, whereas chemical sunscreens use soluble active ingredients that don’t run the risk of settling over time,” she says.

“They are a bit less robust over time. More things can go wrong, little changes in the formula could drop the SPF a lot more than with a chemical sunscreen.”

Ultra Violette founder Ava Chandler-Matthews says that zinc-based sunscreens like hers could be highly unstable and questioned whether Choice’s samples were exposed to heat and extended transport time.

Choice chief executive Ashley de Silva maintains all 20 sunscreens were “decanted, sealed, labelled and transported in accordance with strict instructions provided by an accredited, specialised laboratory”.

“Amber glass jars were used in order to limit any degradation of the sunscreen ingredients, and ensure the validity of our results, as they block UV light more than clear glass jars, and glass is less reactive than plastic. The entire process, including transportation to the Sydney-based Eurofins Dermatest, was undertaken within an hour.”

Dr Stuart Henderson, ultraviolet radiation exposure assessment assistant director at the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), says while the results are “concerning”, “there doesn’t appear to be anything obviously wrong with the way the testing was done. The methodology that’s been reported is all sound.”

Still, he acknowledges the current standard for SPF testing can be incredibly variable.

While Wong agrees that SPF testing in Australia can be very imprecise, she says sunscreens that received the lowest ratings should be investigated.

Why doesn’t the TGA do its own testing?

Ultimately, responsibility for sunscreen approval falls on the TGA, not Choice. “They don’t do spot checks, as we understand, to verify that these tests are accurate,” said Choice’s De Silva.

A TGA spokesperson said in a statement that the organisation is “investigating the Choice findings and will take regulatory action as required”.

Wong would like to see the TGA limit the number of labs approved for SPF testing in Australia, to limit variability.

When this masthead reached out to Health Minister Mark Butler’s office to ask whether the TGA, part of the Department of Health and Aged Care, should conduct its own sunscreen testing, the inquiry was referred back to the TGA.

“The TGA’s current approach reflects a balanced and risk-proportionate model that is consistent with international regulatory practice,” said a TGA spokesperson.

“As the TGA does not conduct testing on humans or animals, they cannot conduct this testing … If a concern is identified that warrants further investigation, the TGA will consider appropriate actions, including testing.”

Henderson says that ARPANSA, as the Australian government’s “primary authority on radiation protection”, “support[s] efforts to ensure that high-quality, safe and effective sunscreen products are available to the community”, but he declined to comment on who should take responsibility for testing. “It’s a matter for [the TGA], but I understand they have said they’ll be investigating the Choice findings.”

The results of any compliance review the TGA undertakes will be published on its website.

Should I still wear sunscreen?

All parties are on the same page about one thing: none of this means you should throw out your sunscreen. Nearly half of Australians are not using adequate sun protection, according to a survey from 2024 funded by the Cancer Council and conducted by the Australian Bureau of Statistics.

The recommended amount for sunscreen is a teaspoon for face, neck and ears, and a teaspoon for each arm and leg, according to the Cancer Council.

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While Wong believes the Choice results warrant further investigation, she emphasised the importance of proper sunscreen use. “The biggest source of sunscreen failure is actually user error, and it’s mostly how much you apply,” she says.

Most people only apply one-quarter to half of the recommended amount, thus rendering even a sunscreen with a higher SPF rating less effective, she says.

Wong pointed to the Nambour study, landmark research that demonstrated for the first time that regular sunscreen use prevents melanoma, even with a SPF15 sunscreen. “Even that is still effective if you apply it properly,” she says.

“Sunscreen should not be thought of as the ultimate protection,” adds Henderson. “It’s important that it’s used in combination with other sun protection measures.”

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