What Sunscreen Chemicals Do to Living Cell Membranes, and Why It Matters for the Environment and the Body

Avobenzone is in 641 of 924 Australian sunscreen products (69.4%), the single most common UV filter on the market. A 2026 study shows that both avobenzone and oxybenzone insert into model cell membranes and disturb them, with avobenzone the stronger of the two, a finding the authors link to how these chemicals build up in living organisms.

Olechowska K, Wyzga B, Hąc-Wydro K (2026) Affinity of Oxybenzone and Avobenzone toward Lipids in Model Membrane Systems: On the Role of Membranes in the Harmful Effect of UV Filters on Living Organisms. Langmuir 42: 17204-17215.

Why does this matter to sunscreen users?

Every cell in every living thing is wrapped in a membrane made of fatty molecules called lipids. That membrane is the first barrier any foreign chemical has to cross to get inside a cell. This study asks a simple question: when avobenzone and oxybenzone reach a cell membrane, what do they do to it?

The answer matters on two fronts. For the environment, these filters wash off skin into waterways and build up in the tissues of fish, coral and other marine life. For people, the authors note that studies have shown these chemicals are absorbed through the skin into the bloodstream and can collect in body fat. Understanding how they behave at the membrane helps explain how they accumulate. This is a laboratory biophysics study using model membranes, not a study of harm in people, and the authors are careful about that limit.

In plain language

Avobenzone (Avo) and oxybenzone (Oxy) are two of the organic chemical UV filters used in sunscreens. The researchers describe them as filters that are "consistently released into the environment and extensively studied in terms of their toxicity and bioaccumulation potential."

To see how these filters interact with cell membranes, the team used a well-established laboratory technique. They built thin films of pure membrane lipids (the kinds found in the membranes of mammals, fish and crustaceans) floating on water, then watched what happened when avobenzone or oxybenzone was introduced. These model films let scientists measure, with precision, whether a chemical inserts into a membrane and how much it disturbs the packing of the lipids.

 

What the researchers did

The team tested four different membrane lipids on their own (phosphatidylcholine, phosphatidylethanolamine, sphingomyelin and cholesterol) plus a four-lipid blend designed to imitate the membrane of a fat cell, chosen because body fat is where oxybenzone is reported to accumulate.

They tested avobenzone alone, oxybenzone alone, and a 1:1 mixture of the two, since the pair are frequently used together in sunscreens and found together in the environment. Using surface-pressure measurements and Brewster angle microscopy (a way of photographing the film’s surface), they tracked how each filter changed the membrane’s fluidity, stability and structure.

What they found

Both filters disturbed the membranes, and avobenzone did so more strongly. The headline conclusion is that "Avobenzone and oxybenzone affect the monolayer properties by increasing their fluidity, decreasing stability, and inducing morphological changes." In plain terms, both chemicals loosened and destabilised the membrane films and changed their structure.

The two were not equal. The authors found that "Although Avo reveals a significantly stronger effect than Oxy, both filters show selectivity in their interactions with the lipids." Avobenzone inserted readily into all the membrane types tested, while oxybenzone, at the densely packed conditions that best mimic a real membrane, largely failed to insert at all.

The filters were also picky about which lipids they targeted. Avobenzone had a stronger effect on sphingomyelin and cholesterol than on the other two lipids, which the authors connect to where each filter might preferentially build up in the body.

The environmental concerns, in the authors’ words

The environmental case is where this paper’s concern runs strongest, and it goes high here because the paper supports it directly.

The authors are blunt that these chemicals are a problem in the environment. They state the available evidence allows them to consider that "these hazardous chemicals pose a real threat to living organisms." These filters do not stay on skin. They wash into waterways during swimming and through wastewater, and they concentrate in aquatic environments.

The coral-reef numbers they cite are striking. According to the paper, in coral reef areas "the concentration of oxybenzone in the U.S. Virgin Islands ranges from 75" micrograms per litre to as high as 1.4 milligrams per litre. These are the kinds of levels linked to reef damage.

The central environmental message of the study is that membrane affinity may help explain bioaccumulation. The authors conclude that "their affinity to particular lipids may correlate with their bioaccumulation potential," meaning the way these filters lock into fatty membranes may be part of why they build up in the tissues of living things.

The human-exposure facts the paper cites

Alongside the environmental work, the authors summarise what other research has found about these filters in people. These are not this study’s own measurements, but the paper reports them as established context.

The authors state plainly that despite decades of use, "there are doubts about their safety for humans." They note that studies show chemical filters applied to skin "are absorbed into the stratum corneum, penetrate through the skin, and eventually enter the bloodstream." More pointedly, they report that in human studies, "concentrations of these substances in plasma are reported to be above the safety norms established by the U.S. Food and Drug Administration."

The accumulation findings are notable. The paper reports that oxybenzone "is not excreted fully via urine but partially remains within the organism and accumulates in adipose tissue," the body’s fat stores, and that more recently "oxybenzone has also been detected in prostatic tissue." The authors also flag the filters’ "potential endocrine-disrupting effect" as a recognised concern.

The caveats the authors keep in view

This is where honesty matters most, because the study’s own conclusions pull against an alarmist reading, and those conclusions must stay visible.

First, the authors do not claim the membrane disruption they measured is how these filters cause harm. Their abstract states directly that "the direct influence of Avo and Oxy on the biomembrane may not be the ground for their toxicity mechanism." They repeat the point in their conclusion: the filters’ "toxicity mechanism may not be directly connected with the disturbances induced at the level of the membrane." What they offer is more modest, that the membrane effect "can be a factor facilitating changes in the cell, leading to the confirmed toxic effects."

Second, and importantly for Australian consumers, the filter that disturbed membranes most strongly is the one generally regarded as safer. The authors note that "avobenzone is considered safer for organisms than oxybenzone," even though their own results show avobenzone has the stronger affinity for lipids.

Third, this is a model-membrane laboratory study. It does not measure disease, dose, or risk in any living person or animal. It is a mechanistic piece that helps explain bioaccumulation, not a verdict on safety.

How common are these filters in Australian sunscreens?

The two filters sit at opposite ends of the Australian market. Across 924 therapeutic sunscreen products on the Australian Register of Therapeutic Goods (ARTG), avobenzone is the most common UV filter of all, appearing in 641 products (69.4%). Oxybenzone, by contrast, is now rare in Australian sunscreens, appearing in just 33 products (3.6%).

So the filter this study found most disruptive to membranes, avobenzone, is also the one Australians are most likely to be using. Oxybenzone, the more notorious of the two internationally and the one most associated with coral-reef damage, has largely fallen out of the Australian market.

Beyond the paper (regulatory context)

Both filters remain approved by the Therapeutic Goods Administration (TGA) for use in Australian sunscreens. Oxybenzone has been banned or restricted in several jurisdictions specifically to protect coral reefs, including Hawaii, Palau and parts of the US Virgin Islands, on environmental rather than human-health grounds. Avobenzone remains widely permitted internationally and is one of the few approved broad-spectrum UVA filters, which is part of why it is so common.

Common questions

Does this study say sunscreen is harmful to my health?

No. It is a laboratory study of how two filters interact with model cell membranes. The authors explicitly say the membrane effect may not be the mechanism of toxicity. The human-exposure facts it cites (absorption into blood, accumulation in fat) come from other research and are presented as context.

Which is worse, avobenzone or oxybenzone?

It depends what you mean. Avobenzone disturbed the model membranes more strongly in this study. But the authors note avobenzone is generally considered safer for organisms than oxybenzone.

Why does the coral-reef issue keep coming up with oxybenzone?

Because oxybenzone reaches high concentrations in reef waters and is linked to coral damage, which is why several places have banned it. This study adds that these filters build up in the fatty tissues of marine life, and that their affinity for lipids may help explain that accumulation.

Is oxybenzone in Australian sunscreens?

Rarely. It appears in only about 3.6% of products on the ARTG. Avobenzone, the other filter in this study, is in nearly 70%. But a real check when buying product is a warranted.

Who did the research?

The study came from the Physicochemical Environmental Research Group in the Department of Environmental Chemistry, Faculty of Chemistry, Jagiellonian University in Kraków, Poland. The group specialises in using model membranes to study how environmental pollutants and other compounds interact with the lipids that build living cells.

Dr Karolina Olechowska (corresponding author). Researcher at the Department of Environmental Chemistry, Jagiellonian University. She received her MSc in chemistry in 2015 and her PhD, awarded with distinction, in 2019, both from the same faculty. Her work focuses on cell-membrane modelling, natural-origin antimicrobial agents, and nanostructured drug-delivery systems. On this paper she led the conceptualisation, data curation, formal analysis, investigation, visualisation, and the original draft.

Beata Wyżga. Doctoral researcher in the same group, working through the Jagiellonian University Doctoral School of Exact and Natural Sciences. Her published work centres on the role of membrane lipids in the action of antimicrobial and preservative compounds. She contributed to the conceptualisation, data curation, formal analysis, investigation and visualisation of this study.

Dr habil. Katarzyna Hąc-Wydro. Head of the research group and the senior author. She has a long record in membrane biophysics using the Langmuir monolayer technique, studying how cholesterol, sphingomyelin and other lipids interact with a wide range of substances. On this paper she provided the conceptualisation, formal analysis, methodology and supervision, and contributed to the original draft.

On the funding. The authors disclose that the study used research infrastructure funded by the European Union through the Smart Growth Operational Programme (the "ATOMIN 2.0" materials research centre). They declare no competing financial interest.

Source

Olechowska K, Wyzga B, Hąc-Wydro K (2026) Affinity of Oxybenzone and Avobenzone toward Lipids in Model Membrane Systems: On the Role of Membranes in the Harmful Effect of UV Filters on Living Organisms. Langmuir 42: 17204-17215.