Toxins Lurking in Your Sunscreen: Ingredients to Avoid

Sunscreen is our go-to defence against the sun's harmful UV rays, protecting skin from sunburn and lowering the risk of skin cancer. But not all sunscreens are created equal, and the ingredients doing the UV-blocking work matter more than most labels let on. A growing body of research shows that several common chemical UV filters absorb through the skin at significant levels, disrupt hormones, and accumulate in the bodies of people who use them regularly. A 2026 University of Queensland study published in Environmental Science & Technology measured urinary concentrations of UV filters in Queensland children aged 1 to 14 and found that homosalate was the most prevalent filter detected, with more than half of children also showing urinary benzophenone-3 concentrations above thresholds associated with potential endocrine effects. That's children heading to school or the beach with what we assume is a protective product.

What the research shows

The Queensland children's study

A 2026 study led by researchers at the University of Queensland and published in Environmental Science & Technology is one of the most detailed pieces of biomonitoring work done on UV filter exposure in children. The researchers collected urine samples from children aged 1 to 14 across Queensland and measured concentrations of multiple UV filters and their metabolites. You can read the full study here: Assessing UV Filter Exposure in Queensland, Australia: Human Biomonitoring Evidence Highlighting Homosalate in Children.

Homosalate was the most commonly detected filter, present in the urine of the majority of children tested. More than half had urinary benzophenone-3 concentrations exceeding thresholds associated with potential endocrine disruption. Children using sunscreen daily showed substantially higher concentrations than those applying it occasionally, and concentrations were highest in the youngest age group. The researchers noted that children's developing hormonal systems make them particularly vulnerable to endocrine-disrupting chemicals, and identified Australian children as among the highest-exposed populations studied globally, partly because of high solar UV intensity and the cultural norm of daily sunscreen use from an early age.

This isn't an isolated finding. Benzophenone-3 and homosalate have been detected in human urine, blood, and breast milk across multiple countries. The Queensland study adds weight to those earlier findings by showing the scale of exposure specifically in young children in a high-sunscreen-use environment.

Oxybenzone: the most studied concern

Oxybenzone (benzophenone-3) is detectable in the bodies of the vast majority of people who use sunscreen regularly. It absorbs through the skin rapidly and accumulates. A 2019 FDA clinical study published in JAMA found that oxybenzone reached blood concentrations far exceeding the agency's proposed threshold for systemic safety after a single day of use, and concentrations continued rising with repeated application.

A study published in International Journal of Andrology found that adolescent boys with higher urinary oxybenzone levels had significantly lower total testosterone. Oxybenzone exposure during pregnancy has been associated with shorter gestational length in pregnancies carrying male fetuses and altered birth weight. The National Toxicology Program found heightened incidence of thyroid tumours in female rats exposed to high oxybenzone concentrations, though the carcinogenic evidence in humans remains inconclusive.

Oxybenzone is also one of the main UV filters implicated in coral reef damage. Hawaii, Palau, and several other jurisdictions have banned it outright for this reason.

Homosalate: detected in most Queensland children, and it accumulates

The 2026 Queensland study is the clearest evidence yet that homosalate is accumulating in children at measurable levels. It was the single most commonly detected UV filter across the cohort, appearing at higher prevalence than oxybenzone. The researchers linked daily sunscreen use directly to higher urinary homosalate concentrations, which means the exposure is coming from the product, not background contamination.

Homosalate is flagged by the FDA as lacking sufficient safety data to be classified as safe and effective. Research has shown it penetrates skin, disrupts hormones, and produces potentially toxic breakdown products over time. The European Commission's Scientific Committee on Consumer Safety (SCCS) recommended in 2022 lowering the permitted concentration of homosalate in sunscreens specifically because of endocrine concerns, though regulatory action across most markets has been slow to follow. Homosalate is present in a very large proportion of commercial sunscreens marketed to families, including many positioned as gentle or everyday options.

Octinoxate: absorbed and hormonally active

Octinoxate (octyl methoxycinnamate) is another widely used organic filter that absorbs through skin readily, and keeps absorbing for hours after application. It's been detected in blood samples at concentrations well above the FDA's proposed safety threshold. Studies have shown octinoxate can disrupt thyroid hormone production and cause photoallergic reactions when UV light interacts with it on skin.

Octisalate: exceeded absorption limits and weak oestrogen activity

Octisalate (octyl salicylate) absorbs through skin at levels significantly exceeding the FDA's threshold for systemic exposure. The FDA does not classify it as safe and effective. It's been linked to allergic contact dermatitis and has been shown to weakly bind to oestrogen receptors, suggesting potential endocrine activity, though the effect size is smaller than oxybenzone.

Octocrylene: absorption and benzophenone contamination

Octocrylene absorbs through skin at levels far above the FDA's acceptable limits for systemic exposure. The FDA acknowledges insufficient data to determine its safety. Of particular concern: octocrylene can degrade into benzophenone, a substance classified as a possible human carcinogen by the International Agency for Research on Cancer. A 2022 study in Science of the Total Environment confirmed benzophenone contamination in multiple commercial sunscreen products containing octocrylene.

Avobenzone: instability and breakdown products

Avobenzone provides UVA protection but is chemically unstable when exposed to sunlight. It breaks down into compounds that have been shown to cause allergic reactions and disrupt the endocrine system. Because of its instability, manufacturers pair it with other UV filters to stabilise it, which means using avobenzone typically means using a cocktail of chemical filters. Blood concentrations of avobenzone have been found to exceed FDA safety thresholds after normal sunscreen use.

Safer materials to choose

The FDA's 2019 proposed sunscreen rule identified only two active ingredients as generally recognised as safe and effective: zinc oxide and titanium dioxide. These are mineral filters. They sit on the surface of the skin and physically scatter and reflect UV radiation rather than absorbing it and undergoing chemical reactions.

Zinc oxide is the stronger of the two for broad-spectrum (UVA and UVB) protection. I prefer zinc oxide based sunscreens, and it's what I use on my family. It covers the full UV spectrum, has a longer track record of safety data, and the non-nano particle form doesn't penetrate skin.

Titanium dioxide provides strong UVB protection but weaker UVA coverage, so it's more common in combination formulas. The key word with both is non-nano: non-nano particles are too large to penetrate skin, which is the relevant safety distinction. Nano-sized particles are small enough to potentially enter cells, which is why particle size matters when you're reading labels.

Mineral sunscreens used to leave a heavy white cast, and that's still true of some formulations. Tinted mineral sunscreens use iron oxides to offset the cast while adding an extra layer of protection against visible light. If you've avoided mineral SPF because of the white cast, a tinted option is worth trying.

Other things worth knowing

Babies under six months old should not use sunscreen, mineral or otherwise. Their skin absorbs substances at a higher rate than older children and adults, and there isn't adequate safety data on sunscreen use in this age group. Shade, protective clothing, and avoiding peak UV hours are the recommended approach for infants under six months.

For babies and young children over six months, mineral sunscreens with non-nano zinc oxide are the appropriate choice. Avoid spray sunscreens for children as inhalation is a real risk, and avoid sunscreens with fragrances or added preservatives like parabens where possible.

If you're pregnant or breastfeeding, oxybenzone is the ingredient to be most cautious about given its detection in breast milk and the associations with pregnancy outcomes in existing studies. Mineral sunscreens are the straightforward alternative, and there's no evidence that non-nano zinc oxide or titanium dioxide present any absorption risk.

Reef-safe labelling in New Zealand and Australia is currently unregulated, meaning any product can use the term regardless of its ingredients. If reef safety matters to you, check the active ingredients directly and avoid oxybenzone and octinoxate specifically.

Sunscreens we recommend

Every sunscreen listed here uses zinc oxide or titanium dioxide as the active ingredient. None contain oxybenzone, octinoxate, homosalate, octisalate, octocrylene, or avobenzone.

Earth's Kitchen Sunscreen

A New Zealand-made mineral sunscreen using non-nano zinc oxide. Clean ingredient list, no synthetic fragrance, and suitable for sensitive skin. Good for everyday facial use.

Goodbye Natural Sun Balm

A physical sunscreen and insect repellent in one, with non-nano zinc oxide as the active. Compact format, good for outdoor activities. Worth noting it doubles as an insect repellent, which is useful on summer days.

Ocean and Orchard Baby & Kids Sunscreen

Formulated specifically for babies and children, with non-nano zinc oxide. Available in a 1kg size, which makes it practical for families going through sunscreen quickly over a summer. Fragrance-free and without the unnecessary extras found in many kids' sunscreens.

Smidge Sunscreen

A mineral SPF with a light finish that works well under makeup or on its own. Non-nano zinc oxide, no chemical filters. Popular for daily facial use.

SunButter Original Sunscreen SPF50

An Australian-made SPF50 with a tinted finish that suits a range of skin tones. Active ingredient is non-nano zinc oxide. The tinted formula helps offset the white cast that can come with high-zinc formulations.

Avocado Zinc SPF 50 Natural Physical Sunscreen

Non-nano zinc oxide with avocado oil as a key carrier ingredient. A solid everyday option with a straightforward ingredient list.

Avocado Zinc SPF 50 Natural Tinted

The tinted version of the above. The iron oxide pigments give a skin-tone finish and provide additional protection against visible light, which is relevant for people concerned about hyperpigmentation.

Edible Beauty Basking Beauty Natural Sunscreen

A clean-formulated mineral sunscreen with non-nano zinc oxide. Australian made, with a focus on skin-nourishing ingredients alongside the SPF active.

You can also see the full sunscreen product guide here:

See all sunscreen recommendations

Quick summary

• Avoid sunscreens containing oxybenzone, octinoxate, homosalate, octisalate, octocrylene, and avobenzone.
• Choose non-nano zinc oxide or titanium dioxide as the active ingredient.
• For children and pregnant or breastfeeding women, mineral sunscreens are the clear choice.
• Babies under six months should not use sunscreen; use shade and protective clothing instead.
• Tinted mineral sunscreens are a practical option if white cast has put you off mineral SPF in the past.
• Reef-safe labelling is unregulated in NZ and AU; check the actual ingredients rather than relying on the claim.

Some affiliate links in this post.

References

1. Heffernan, A. et al. (2026). Assessing UV Filter Exposure in Queensland, Australia: Human Biomonitoring Evidence Highlighting Homosalate in Children. Environmental Science & Technology. https://pubs.acs.org/esthag/article/doi/10.1021/acs.est.6c09445/5421346/Assessing-UV-Filter-Exposure-in-Queensland
2. Matta, M.K. et al. (2019). Effect of Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active Ingredients. JAMA. https://pubmed.ncbi.nlm.nih.gov/30933248/
3. Scinicariello, F. & Buser, M.C. (2016). Serum Testosterone Concentrations and Urinary Bisphenol A, Benzophenone-3, Triclosan, and Paraben Levels in Male and Female Children and Adolescents. Environmental Health Perspectives. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4592813/
4. Wolff, M.S. et al. (2008). Prenatal Phenol and Phthalate Exposures and Birth Outcomes. Environmental Health Perspectives. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4609273/
5. National Toxicology Program (2012). Toxicology and Carcinogenesis Studies of Oxybenzone. NTP Technical Report 597. https://ntp.niehs.nih.gov/sites/default/files/ntp/htdocs/lt_rpts/tr597_508.pdf
6. FDA (2019). Sunscreen Drug Products for Over-the-Counter Human Use. Federal Register. https://www.federalregister.gov/documents/2019/02/26/2019-03019/sunscreen-drug-products-for-over-the-counter-human-use
7. Krause, M. et al. (2012). Sunscreens: are they beneficial for health? An overview of endocrine disrupting properties of UV-filters. International Journal of Andrology. https://pubmed.ncbi.nlm.nih.gov/22612478/
8. Ruszkiewicz, J.A. et al. (2022). Benzophenone contamination in octocrylene-containing sunscreen products. Science of the Total Environment. https://www.sciencedirect.com/science/article/abs/pii/S0048969722061733
9. SCCS (2022). Opinion on homosalate. European Commission Scientific Committee on Consumer Safety. https://health.ec.europa.eu/system/files/2022-08/sccs_o_244.pdf
10. Coronado, M. et al. (2008). Endocrine disrupting activity of UV-filters. Toxicological Sciences. https://pubmed.ncbi.nlm.nih.gov/17177714/

Frequently Asked Questions

Is mineral sunscreen better than chemical sunscreen?

For human health and environmental impact, the evidence currently favours mineral sunscreens using non-nano zinc oxide or titanium dioxide. Chemical UV filters like oxybenzone, octinoxate, and homosalate absorb into the bloodstream at levels that exceed FDA safety thresholds and have been linked to hormone disruption. A 2026 University of Queensland study published in Environmental Science & Technology found homosalate was the most prevalent UV filter detected in children's urine, with more than half of children also showing elevated benzophenone-3 concentrations. Mineral filters sit on the skin surface and have a much stronger safety record. The FDA's 2019 proposed rule identified only zinc oxide and titanium dioxide as generally recognised as safe and effective.

What is the best mineral sunscreen in New Zealand?

Several good options are available in NZ, including Earth's Kitchen Sunscreen, Ocean and Orchard Baby and Kids Sunscreen, Smidge Sunscreen, and Avocado Zinc SPF 50. All use non-nano zinc oxide as the active ingredient without chemical UV filters. Tinted options like SunButter SPF50 and Avocado Zinc Tinted are worth considering if white cast is a concern.

Which sunscreen is best for babies?

For babies over six months, choose a mineral sunscreen with non-nano zinc oxide as the only active ingredient. Avoid fragrances, parabens, and any chemical UV filters. Ocean and Orchard Baby and Kids Sunscreen is a good option. Babies under six months should not use sunscreen at all; use shade, protective clothing, and a wide-brimmed hat instead.

Why shouldn't babies under 6 months use sunscreen?

Babies under six months have skin that absorbs substances at a higher rate than older children, and there is no adequate safety data on sunscreen use in this age group. Health authorities including Plunket and the Cancer Society recommend keeping infants under six months out of direct sun, using shade structures, and dressing them in lightweight protective clothing and hats rather than applying sunscreen.

Can I use mineral sunscreen while breastfeeding?

Yes, mineral sunscreens with non-nano zinc oxide or titanium dioxide are considered safe during breastfeeding. Oxybenzone is the ingredient to avoid: it has been detected in breast milk and is associated with endocrine disruption. Switching to a non-nano mineral SPF removes that concern.

What is the best non-toxic sunscreen?

The safest sunscreens use non-nano zinc oxide as the active ingredient, with no oxybenzone, octinoxate, homosalate, octisalate, octocrylene, or avobenzone. Look for fragrance-free formulas with short, recognisable ingredient lists. Brands we recommend include Earth's Kitchen, Smidge, Ocean and Orchard, Avocado Zinc, SunButter, and Edible Beauty, all of which are available in NZ and Australia.