The researchers analyzed 187 pooled urine samples representing approximately 18,700 Australians collected between 2012 and 2023 [1]. For the homosalate metabolite HMS-CA5, 80% of children's pooled samples exceeded the German Human Biomonitoring Commission's HBM-I value (Human Biomonitoring-I value), which the study describes as the level below which no health effects are expected [1].
The researchers found that 53% of children's pooled samples exceeded the HBM-II value, defined in the study as the level at which adverse health effects are possible and indicating an acute need for exposure reduction and biomedical advice [1].
The findings place a commonly used UV filter at concentration levels that German guidance associates with possible health risk in a vulnerable population.
Biomonitoring Data Shows Widespread Exceedances
The study reports that the HBM-I value for HMS-CA5 in children and men is 0.16 micrograms per liter, while the HBM-II value is 0.49 micrograms per liter [1]. The researchers found that from 2018 onward, every children's pooled sample exceeded the HBM-I value. The first HBM-II exceedances in children appeared as early as 2016 [1].
In 100% of children's pooled samples, the most sensitive biomarker for each of the three UV filters investigated was present above the laboratory limit of quantification, according to the study. Children had roughly one order of magnitude higher biomarker concentrations than adolescents and adults for several of the UV-filter biomarkers studied [1].
The pattern suggests that children, whose developing systems may be more susceptible to chemical exposures, carry a body burden of these compounds that is consistently higher than that of older age groups. The Australian Sunscreen Council described the findings as a landmark study indicating homosalate could be harming 50% of Queensland children [1].
Australian broadcast outlets reported the study's central finding that children showed high levels of homosalate, described as a potential hormone disruptor commonly used in sunscreens [2].
Kidney Toxicity Identified as Critical Health Endpoint
The study states that the HBM values for homosalate were derived using toxicological evidence that identified adverse effects in the kidneys as the critical endpoint [1]. The study's risk-assessment table lists the critical effect for both cis-homosalate and trans-homosalate as adverse effects in the kidneys [1].
The kidney findings follow earlier regulatory scrutiny of homosalate for potential endocrine effects and reproductive toxicity. The Therapeutic Goods Administration's (TGA) 2025 safety review of seven active sunscreen ingredients considered evidence for the ability of these ingredients to penetrate the skin and reach viable cells systemically, and it recommended regulatory controls for homosalate and oxybenzone to restrict their permitted concentrations and use in therapeutic sunscreens [1][3].
According to that review, the existing data was not adequate to establish causality in humans, and further investigation was warranted. The study's identification of kidney effects as the critical endpoint provides a toxicological basis for the guidance values that the Queensland biomonitoring data exceeded.
Regulatory Review and FOI Documents Detail Prior Concerns
The TGA's Australian Sunscreen Exposure Model found that the Margin of Safety was below 100 for homosalate and oxybenzone when general sunscreen was applied to the body at the maximum permitted concentration.
Freedom of information documents obtained by the Australian Sunscreen Council and published in July 2026 record TGA consideration of possible effects relevant to the kidneys, fertility and development [1]. The TGA's nonclinical assessment reviewed a combined repeat-dose and reproductive and developmental toxicity study and established a general toxicity NOAEL of 120 milligrams (mg) per kilogram per day, while a reproductive and developmental NOAEL could not be reliably established, according to the released documents [1].
Those documents indicate that the agency had already weighed concerns about kidney, fertility and developmental endpoints before the biomonitoring study was published [1]. The Australian Sunscreen Council has called for urgent regulatory intervention on sunscreen chemicals in Australia [4].
Children Had Higher Exposure; AMA Responds
The study authors concluded that the findings indicate the need to reduce homosalate exposure in at least some individuals and confirmed the necessity for stricter regulations for homosalate in Australia. The researchers specifically raised the possibility that tighter restrictions could focus on products intended for children.
Australian Medical Association Queensland President Dr. Nick Yim told The Courier-Mail that while sunscreen plays a vital role in preventing skin cancer, especially in Queensland, some chemicals could cause harm as research increases. The Courier-Mail reported that half of Queensland children have enough of a sunscreen-linked chemical in their bloodstream to impact their health, citing the international study [5].
The U.S. Food and Drug Administration (FDA) has determined that sufficient data is available to support zinc oxide as Generally Recognized as Safe and Effective (GRASE) for sunscreen use [1]. The agency has stated that the available record does not contain sufficient data to make the same positive determination for homosalate and other chemical UV filters. [1].
Researchers Call for Stricter Regulation; TGA Has Proposed Restrictions
Researchers warned that a loss of confidence in sunscreen safety could lead to ineffective sun-protection behavior, according to the study. The authors' concern is that if consumers abandon sunscreen over safety questions, skin cancer prevention efforts could suffer [1].
The TGA proposed restrictions in July 2025, including listing homosalate in the Poisons Standard and reducing its permitted concentration in therapeutic sunscreens, according to the FOI (Freedom of Information) documents [1][3]. The proposed controls would restrict both concentration and use in therapeutic sunscreens.
The study authors include researchers with expertise in human biomonitoring, toxicology, environmental exposure science, epidemiology, analytical chemistry and pathology from Australia and Germany.
References
- Landmark Study Finds Homosalate in Sunscreens Could Be Harming 50% of QLD Children. https://www.australiansunscreencouncil.org/blog
- Queensland Study Finds High Homosalate Levels in Children .... https://www.facebook.com/7NEWSQld/videos/chemical-found-in-sunscreen-under-review-as-health-concerns-emerge/943825208149906/
- Safety review of seven active sunscreen ingredients. https://www.tga.gov.au/sites/default/files/2025-04/safety-review-seven-active-sunscreen-ingredients.pdf
- ASC Calls for TGA Action on 4-MBC in Children's Sunscreens. https://www.australiansunscreencouncil.org/post/australian-sunscreen-council-tga-action-4-mbc-sunscreens
- Study finds harmful sunscreen chemical in half of Qld children. https://www.heraldsun.com.au/health/wellbeing/cosmetic-health/study-finds-harmful-sunscreen-chemical-in-half-of-qld-children/news-story/8c9b451979a76e5ec608a4ded6a37083
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