Australian shoppers often pay more for mineral sunscreens like Invisible Zinc and Naked Sundays, believing they are gentle and natural because of zinc oxide. But new tests by the University of New South Wales (UNSW) show a spicy secret: these pricey brands use hidden chemical filters too! Mineral sunscreens typically bank on zinc oxide to block the sun’s UV rays, and they are sold as better for sensitive skin. Yet, UNSW’s chemistry team tested 10 popular sunscreens, including Invisible Zinc's kid-friendly version and Naked Sundays’ $58 skin tint, and found that both have unlisted chemical ingredients helping to boost their sun protection. Some mineral sunscreens cost as much as $82 for just 50ml, but what’s inside isn’t just minerals! According to UNSW Prof Jon Beves, “If a sunscreen is giving the illusion that it only contains so-called mineral components … it’s very likely it contains almost identical stuff as other sunscreens and that’s what makes them work so well.” Normally, sunscreens work by absorbing or reflecting UV light. UNSW's study revealed zinc oxide works partly by absorbing UV too, like chemical filters do. But many brands sneak in chemicals like butyloctyl salicylate and ethylhexyl methoxycrylene without calling them “active” ingredients. These chemicals protect skin but don't need to be registered with Australia's Therapeutic Goods Administration (TGA). In a broader look at 143 mineral sunscreens registered with the TGA, over one-third had these unregulated chemical filters. Nearly 25% contained the two chemicals that make the sunscreen feel smooth and absorb UV safely. How did UNSW find the hidden sunscreens? They spread each product on a special glass that never blocks UV and shined UV rays through. Analyzing the pattern, they spotted chemical filters working behind the scenes. Invisible Zinc’s Junior Mineral Sunscreen SPF50 claimed zinc oxide as the only active ingredient. But lab tests showed chemicals like butylocyl salicylate were also key in sunscreen power. Invisible Zinc’s maker, iNova Pharmaceuticals, responded that the chemicals are listed as “other” ingredients and denied hiding anything. They said, “It is true that both [butyloctyl salicylate and ethylhexyl methoxycrylene] absorb UV, however, that is not their primary function in our formulation.” Naked Sundays stayed quiet, but UNSW found similar hidden chemical action in its BeautyScreen SPF50 Peptide Foundation Tint, which only lists zinc oxide as active. Because it’s sold as a cosmetic, it’s not required to register with the TGA or list ingredients fully. The sunscreen industry is under pressure. Earlier, consumer group Choice triggered a scandal about SPF claims, and the TGA pulled some sunscreens and is rethinking how to regulate SPF testing. UNSW scientists say their tests show a “best-case scenario,” as real skin interaction might change things. Meanwhile, the TGA may move to lab tests away from human volunteers for SPF. So next time you reach for that expensive mineral sunscreen, remember: you might be paying for secret chemical helpers that do the same job as cheaper sunscreens!