Australian consumers are paying a premium for “mineral” sunscreens that contain almost the same chemicals as cheaper varieties, new testing has revealed.
The School of Chemistry at the University of New South Wales tested 10 sunscreens, including Invisible Zinc Children’s Sunscreen and a Naked Sunday Skin Tint, which has a retail price of $58 – both of which are marketed as mineral sunscreens.
Mineral sunscreens, which often contain zinc oxide, are usually marketed as more “natural” and gentle on the skin, and are sometimes described as reflecting UV.
They tend to be much more expensive than normal supermarket or pharmacy products.
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The study found that while all 10 products exceeded their sun protection factor (SPF) claims, some of the protection provided by the Invisible Zinc and Naked Sunday products actually came from chemicals not identified on the bottle.
Researchers found that a range of products contained chemical filters that were not listed as active ingredients, with prices for some mineral sunscreens as high as $82 for a 50 ml bottle.
UNSW Professor John Bewes said, “If a sunscreen is giving the illusion that it only has so-called mineral ingredients… then it is very likely that it contains the same things as other sunscreens and that is what makes them work so well.”
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Sunscreens usually work by creating a barrier between the skin and the sun’s rays by absorbing UV radiation.
The UNSW study found that while zinc oxide reflects UV, it acts similar to a “chemical” filter through absorption.
Researchers also found that some brands include other UV-absorbing chemicals in mineral sunscreens, without fully disclosing to consumers.
Most sunscreens in Australia are registered with the Therapeutic Goods Administration (TGA), which requires the submission of SPF test results and a list of ingredients.
But some do not require TGA registration, as the brands describe them as cosmetic products, meaning they are subject to fewer regulations and do not need to disclose any ingredients.
Unregulated chemicals in one-third of ‘mineral’ sunscreens
A comprehensive review by UNSW researchers, which examined 143 sunscreens registered with the TGA that only listed mineral filters such as zinc oxide as active ingredients, found that more than a third also contained unregulated chemical filters.
About 25% of products contain butyloctyl salicylate and ethylhexyl ethoxycrylene, chemical filters that protect against UV radiation but are not required to be listed as “active” ingredients with the TGA because they are not regulated.
UNSW’s Dr Anna Wang said these chemicals are used to make products feel good on the skin, but they also absorb UV, just like the common sunscreen ingredients ethylhexyl salicylate and octocrylene. Both ingredients are regulated by the TGA, making them subject to safety review.
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To test the sunscreens, UNSW scientists spread films of each product on quartz, a type of glass that doesn’t absorb UV on its own.
They used a device that could pass UV light through each sunscreen’s film to see how much light was absorbed and reflected, and compared the patterns shown by zinc oxide to “chemical” filters.
In the case of Invisible Zinc Junior Mineral Sunscreen SPF50, UNSW testing found that zinc oxide was not the only ingredient providing sun protection, despite the company advertising otherwise.
On the TGA register, its manufacturer, Ionova Pharmaceuticals, claims zinc oxide is the product’s only “active” ingredient. It lists butylsalicylate and ethylhexyl ethoxycrylene as “other” ingredients.
The UNSW research found there was “no doubt” that these other chemicals contributed to the sunscreen’s SPF performance.
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On its website, Invisible Zinc claims that the sunscreen contains “no chemical UV filters.”
A spokesperson for Inova said that claims that the chemicals were hidden were “categorically false”, as they were disclosed in the product’s TGA listing.
“It is true that both (Butyloctyl Salicylate and Ethylhexyl Methoxycrylene) absorb UV, however, this is not their primary function in our formulation,” he said.
“We stand by the claims associated with Invisible Zinc Junior Mineral Sunscreen, particularly as micronized zinc oxide is the only active ingredient.”
Naked Sundays did not respond to Guardian Australia’s requests for comment.
But UNSW researchers said its BeautyScreen SPF50 Peptide Foundation Tint gave the same results as Invisible Zinc.
On its website, the product lists zinc oxide 12% as its only active ingredient. Butyloctyl salicylate is named as an “inactive” ingredient, but UNSW researchers said the chemical is “definitely increasing the SPF” of the product.
Because it is considered a cosmetic, the product does not need to be registered with the TGA or list its ingredients on the regulator’s website.
Sunscreen Industry Under the Microscope
The UNSW research was conducted several months after consumer advocacy group Choice revealed a scandal in June with its investigation of the SPF claims of popular sunscreen brands.
The industry has previously run on an honor system: Sunscreen brands are “self-certified”, they have tested SPF claims, and the TGA usually doesn’t do its own testing.
But following the Choice investigation, the TGA withdrew a range of sunscreens and is considering changes to the way it regulates the industry, including how products should be tested.
The UNSW researchers said their calculations were “best case” because their test could not account for potential interactions between sunscreen and skin, especially if it was absorbed or washed off.
However, the TGA has said that variability between people presents problems in testing sunscreens on human skin. The regulator is considering a change from the accepted method of using human volunteers to in vitro SPF testing.
The TGA has been contacted for comment.
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