Australian Sunscreen Council members publish world-first peer-reviewed paper on Australian sunscreen composition and safety implications

Australian Sunscreen Council expert member and toxicologist Dr Abhinandan “Rocky” Chowdhury and ASC Director and Chief Advisor for Industry Joseph Mizikovsky have published the first peer-reviewed population-level analysis of the chemical UV-filter composition of Australia’s active AUST L therapeutic sunscreen market.

The Australian Sunscreen Council is proud to announce the publication of landmark Australian research examining what is actually inside the therapeutic sunscreens Australians are encouraged to apply every day.

Published in the peer-reviewed journal Toxicology Reports, the study by Dr Abhinandan Chowdhury and Joseph Mizikovsky analysed the UV-filter composition of 924 unique therapeutic sunscreens listed on the Australian Register of Therapeutic Goods.

It is the first study to characterise the multi-filter composition of Australia’s active AUST L therapeutic sunscreen market at population level—and to examine what that composition means for the way sunscreen safety is assessed. The paper was published online on 9 August 2026 and is freely available through PubMed Central.

A world-first analysis of Australia’s therapeutic sunscreen market

Previous research has investigated individual sunscreen ingredients, selected products or small collections of formulations.

Until now, however, no peer-reviewed study had examined the composition of the therapeutic sunscreen formulations actually on sale across Australia at population level.

Chowdhury and Mizikovsky extracted all therapeutic sunscreens with an active AUST L designation from the ARTG. After removing duplicate listings and products that were not sunscreens, the researchers were left with 924 unique products representing the Australian therapeutic sunscreen market captured by the study in January 2026.

This complete market-level approach allowed the researchers to move beyond theoretical ingredient assessments and establish how chemical UV filters are combined in real Australian products.

The results show that chemical UV-filter mixtures are not an unusual or occasional feature of Australian sunscreens.

They are the norm.

Every chemical-filter sunscreen contained a mixture

Of the 924 therapeutic sunscreens examined:

187 products, or 20.2%, were mineral-only sunscreens.

The remaining 737 products, or 79.8%, contained chemical UV filters—and every one of those 737 products contained at least two chemical UV filters.

More than 85% contained four or more chemical UV filters, while 39.5% contained five or more. Combined chemical UV-filter concentrations commonly represented 15% to 25% of the entire formulation by weight.

Twenty different UV-filter actives were identified across the market. The most frequently declared were avobenzone, appearing in 641 products; octocrylene, in 600; octyl salicylate, in 411; homosalate, in 410; and zinc oxide, in 243.

Lead author Dr Abhinandan Chowdhury summarised the finding plainly:

“These aren’t single-chemical products.”

The typical Australian chemical-filter sunscreen is not one independently acting UV filter placed into a neutral base. It is a formulation containing several UV filters, often at a substantial combined concentration, applied to the same person at the same time.

Why sunscreen composition changes the safety question

Australia’s sunscreen toxicology framework primarily calculates a Margin of Safety for each active ingredient separately.

That approach may estimate whether one chemical UV filter satisfies an ingredient-specific safety threshold under the assumptions used in the model.

It does not necessarily establish the safety of a formulation containing four, five or six chemical UV filters acting together.

The new paper identifies a fundamental mismatch between the unit being assessed and the product being used:

The regulatory calculation is performed on an individual active ingredient. The Australian consumer applies a multi-filter mixture.

Separate calculations for ingredients A, B, C and D do not automatically constitute a cumulative assessment of a product containing A, B, C and D together.

Each individual calculation can be correct within its assumptions while the combined exposure remains unexamined.

This is particularly important where co-formulated chemicals may affect common biological systems, generate additional chemicals after application or behave differently inside a finished formulation.

Chemical UV filters can contribute to shared biological pathways

The paper’s safety analysis did not stop at counting the number of filters on product listings.

Chowdhury and Mizikovsky conducted a targeted toxicological review of nine recurring chemical UV filters and identified several biological and formulation-related reasons why assessing each active independently may not adequately characterise the finished product.

The paper identifies “shared endocrine targets” among frequently co-formulated chemical UV filters.

These include evidence relating to estrogen, androgen and thyroid signalling, as well as oxidative-stress pathways. The significance is not that every chemical necessarily produces the same effect at the same potency. It is that different chemicals may contribute to a common biological target or outcome.

Where several chemicals can act through the same receptor, hormone system or adverse pathway, assessing each one as though the other chemicals are absent may fail to capture their combined contribution.

The appropriate question is not simply whether each chemical sits below its individual threshold.

It is whether the chemicals should be grouped and assessed cumulatively because they act on related biological systems.

Sunlight can produce additional chemicals that are not included in the original calculation

Sunscreens are deliberately placed in direct sunlight.

Chemical UV filters absorb ultraviolet energy and can undergo photochemical reactions, oxidation or degradation during use. The substances originally placed into the bottle may therefore not be the only substances present after the product is applied and exposed to sunlight.

The paper identifies photochemical and oxidative-stress mechanisms capable of generating “additive transformation products.”

These transformation products may have their own chemical and biological properties. Yet they are not comprehensively added together across all of the chemical UV filters contained in a finished sunscreen when individual Margins of Safety are calculated.

In a formulation containing several chemical UV filters, this omission can occur across multiple actives simultaneously.

The finished formulation can change dermal penetration

Chemical UV filters are not applied to skin as isolated laboratory substances.

They are delivered through complex formulations containing solvents, emollients, emulsifiers, film-formers and other ingredients that can affect how chemicals move across or remain within the skin.

The paper identifies co-formulation with “documented dermal penetration enhancers” as another structural limitation of assessing chemical UV filters separately.

Dermal absorption is a central input in calculating systemic exposure and a Margin of Safety. If the finished formulation changes the penetration, stability or residence time of an active ingredient, an exposure estimate developed for that ingredient under different conditions may not accurately represent the product people actually apply.

The safety question must therefore extend beyond the identity and percentage of each active.

It must also consider how those actives behave when combined in the final formulation.

Exposure does not necessarily begin and end with sunscreen application

The paper also identifies exposure pathways that are excluded from a sunscreen-only, ingredient-by-ingredient calculation.

Chemical UV filters have been investigated in indoor air, indoor dust, human milk and chlorinated water. People may also encounter the same filters through cosmetics and other personal-care products.

The study does not suggest that every possible source necessarily contributes an unsafe dose.

It establishes that these additional pathways are not presently incorporated into the calculation used to characterise the combined exposure from multi-filter sunscreen products.

The result is both a mixture-exposure gap and an aggregate-exposure gap.

A person may be exposed to several chemical UV filters from one sunscreen and may also encounter some of those chemicals through additional products or environmental pathways.

A precise calculation for one ingredient from one exposure route does not automatically describe that person’s total relevant exposure.

The cumulative risk is not established as low—it remains uncharacterised

The paper does not claim that every multi-filter sunscreen has been proven to cause harm.

It demonstrates that the combined risk of the mixtures Australians actually apply has not been characterised by separate single-ingredient assessments.

The authors’ conclusion is direct:

The “cumulative risk remains uncharacterised.”

That wording matters.

“Uncharacterised” does not automatically mean harmful. But it also does not mean safe, negligible or low.

It means the assessment required to reach a scientifically supported conclusion about cumulative risk has not been completed.

Dr Chowdhury explained the distinction in announcing the publication:

“The cumulative risk isn’t ‘low.’ It’s uncharacterised.”

He added:

“The failure isn’t the sunscreen — it’s a framework.” 

The absence of a cumulative safety assessment must not be presented as evidence of cumulative safety.

Australians are already applying these mixtures. It is the combined toxicological risk that remains unanswered.

The paper presents a practical way forward

Importantly, the study does not merely identify the problem.

Chowdhury and Mizikovsky conclude that a “mixture-based evaluation framework is feasible.”

The most common chemical UV-filter combinations can be identified using ARTG composition data. Filters can then be grouped according to shared biological targets, common mechanisms, transformation products and relevant exposure pathways.

Established mixture-risk tools—including dose addition, pathway grouping and hazard-index approaches—can then be applied where justified by the evidence.

Representative finished formulations can also be evaluated to determine whether formulation ingredients alter dermal penetration, chemical stability or the formation of transformation products.

The research therefore gives Australian regulators both a reason and a practical foundation to move from isolated ingredient calculations towards a pathway- and mixture-based evaluation of the products Australians actually use.

About lead author Dr Abhinandan “Rocky” Chowdhury

Australian toxicologist, risk-assessment specialist and ASC expert member

Dr Abhinandan “Rocky” Chowdhury, PhD, is the first and lead author of the study and an expert member of the Australian Sunscreen Council.

Dr Chowdhury is an Australian toxicologist specialising in exposure-based risk assessment, topical-product safety, UV-filter toxicology, biological mechanisms and regulatory science.

He holds a Bachelor of Science in Biotechnology, a Master of Science in Analytical Bioscience and a PhD in Toxicology. His multidisciplinary training brings together biotechnology, analytical instrumentation, cellular toxicology, exposure science and regulatory risk assessment.

At the Australian Sunscreen Council, Dr Abhinandan Chowdhury provides specialist toxicological expertise supporting ingredient-safety evaluation, regulatory submissions, evidence-based public education and the development of stronger sunscreen-safety standards.

His work is particularly focused on translating complex mechanistic and exposure evidence into regulatory questions that can be tested, verified and acted upon.

In this study, Dr Chowdhury brought together the market-wide ARTG dataset and the toxicological evidence needed to examine whether Australia’s current assessment framework corresponds with the products Australians actually apply.

That combination of large-scale product analysis and mechanistic toxicology positions Dr Abhinandan Chowdhury as an important Australian researcher in cumulative exposure, sunscreen-mixture toxicology and topical-product safety.

About co-author Joseph Mizikovsky

ASC Director, sunscreen regulatory strategist and standards specialist

Joseph Mizikovsky is the study’s co-author, a Director of the Australian Sunscreen Council, CEO of one of Australia's largest Sunscreen Manufacturers VeganicSKN and the Council’s Chief Advisor for Industry.

Mizikovsky specialises in sunscreen formulation, therapeutic-goods regulation, international UV-filter requirements, industry standards, product development and the practical operation of Australia’s sunscreen supply chain.

He is also a member of Standards Australia’s CS-042 Sunscreen Agents Committee, contributing industry and regulatory expertise to the development and review of Australian sunscreen standards.

Mizikovsky’s contribution to the paper connected its toxicological analysis with the realities of sunscreen formulation and regulation: how active ingredients are combined, how products are entered on the ARTG, how formulations are manufactured and how ingredient-level regulatory decisions affect finished products.

The published contributor statement credits Joseph Mizikovsky with validation and review and editing of the research.

His role was particularly important because mixture toxicology cannot be considered in isolation from formulation practice. Understanding what Australians are exposed to requires knowledge of both biological risk and the way commercial sunscreens are actually designed and supplied.

This combination positions Joseph Mizikovsky as a leading Australian specialist in sunscreen regulation, SPF formulation, standards and cumulative chemical UV-filter policy.

Complementary expertise produced a new Australian evidence base

Dr Abhinandan Chowdhury and Joseph Mizikovsky brought complementary expertise to the study.

Dr Chowdhury contributed toxicology, biological-mechanism analysis, exposure assessment and market-data investigation.

Mizikovsky contributed sunscreen formulation, ARTG, standards, regulatory strategy and industry implementation expertise.

Together, the researchers created a new evidence base that connects three questions rarely examined at the same time:

What is inside Australian therapeutic sunscreens?

How are those chemical UV filters combined?

Does the current safety framework assess the resulting combination?

The study’s answer to the final question is clear: separate single-ingredient Margin of Safety calculations do not, by themselves, characterise the cumulative exposure created by multi-filter formulations.

A significant achievement for Australian sunscreen science

This publication represents an important achievement for the Australian Sunscreen Council and for independent Australian sunscreen research.

It demonstrates the value of bringing toxicologists, formulators, standards specialists and regulatory experts together to examine sunscreen safety as a complete system rather than as a collection of isolated ingredients.

The Australian Sunscreen Council supports effective protection from excessive ultraviolet radiation. It also believes products recommended for frequent, repeated and whole-body use should be evaluated according to their actual composition and realistic exposure conditions.

These positions are not in conflict.

Better sunscreen toxicology strengthens public confidence in sun protection.

The ASC believes the findings justify a formal Australian program to assess commonly used chemical UV-filter combinations, shared biological pathways, finished-formulation penetration, metabolites, degradants and aggregate exposure.

The product is a mixture.

The exposure is to a mixture.

The safety assessment must characterise the mixture.

Study details

Authors: Dr Abhinandan Chowdhury and Joseph Mizikovsky

Journal: Toxicology Reports

Volume: 17

Article number: 102326

Published online: 9 August 2026

DOI: 10.1016/j.toxrep.2026.102326

PMID: 42633302

PMCID: PMC13499350

Paper: Australian therapeutic sunscreens are multi-filter mixtures: Single-ingredient Margin of Safety assessment does not address cumulative exposure.