The Role of Octocrylene in Sunscreens Is Now Under Reassessment

A widely used UV filter facing new regulatory scrutiny

Octocrylene has long been used in chemical sunscreens to absorb UVB radiation and to stabilise other UV filters such as avobenzone. Its performance profile is well established, and it remains permitted in many countries at concentrations of up to 10 percent. However, the scientific and regulatory context surrounding octocrylene has shifted. New evidence on systemic absorption, degradation pathways, and cumulative exposure has prompted a re-examination of whether historical use limits remain appropriate under modern safety standards.

Systemic exposure is now clearly established

Human maximal-use studies have confirmed that octocrylene is absorbed through the skin and enters systemic circulation. Measured plasma concentrations following routine sunscreen use exceed thresholds used by regulators to trigger additional toxicological evaluation, and these levels persist for days after application stops. This persistence indicates slow elimination and raises the possibility of steady-state systemic levels with repeated daily use, although progressive bioaccumulation has not been demonstrated.

Australian sunscreen use magnifies exposure considerations

In Australia, sunscreen is used more frequently and in larger quantities than in many other regions. Public health guidance encourages full-body application, regular reapplication, and year-round use due to high ultraviolet exposure. When these Australian-specific use patterns are applied to exposure modelling, estimated systemic doses of octocrylene increase under Australian high-use conditions, reducing the buffer between estimated exposure and toxicological reference values.

Benzophenone formation has become a central issue

One of the most significant developments in the octocrylene safety discussion is its demonstrated degradation into benzophenone over time. Benzophenone is classified as a possible human carcinogen and is also recognised for endocrine activity. Studies have shown that benzophenone levels in octocrylene-containing sunscreens increase during product ageing, even under normal storage conditions. This means that consumer exposure is not limited to octocrylene itself, but includes a known hazardous degradation product.

The TGA has formally recognised this concern

In 2025, the Therapeutic Goods Administration released a public consultation proposing a specific impurity limit for benzophenone in sunscreen products. This consultation reflects regulatory recognition that benzophenone exposure, including that arising from octocrylene degradation, represents a safety concern that requires active control. Importantly, the consultation acknowledges that impurity levels can increase over a product’s shelf life, not just at the point of manufacture.

Lowering benzophenone means lowering octocrylene

A key finding from recent regulatory submissions is that benzophenone formation from octocrylene is predictable and proportional. Analytical studies show a clear relationship between the percentage of octocrylene in a formulation and the amount of benzophenone that forms over time. When this relationship is applied to the TGA’s proposed benzophenone impurity limits, analytical data submitted to regulators indicate that sunscreens formulated with octocrylene at current permitted levels may exceed those limits over their shelf life under typical formulation and storage conditions. The only effective way to reduce benzophenone formation is to significantly reduce the concentration of octocrylene itself.

Why traditional safety margins are no longer sufficient

Standard margin of safety calculations focus on the parent compound and assume stable composition over time. They do not account for in situ formation of hazardous impurities such as benzophenone, nor do they capture real-world factors such as high-frequency reapplication, formulation interactions, or product ageing. As a result, a margin of safety that appears acceptable on paper may not reflect actual consumer exposure over months or years of use.

Environmental persistence adds to cumulative risk

Octocrylene and benzophenone have both been detected in aquatic environments, particularly in high-use coastal areas. Their persistence in water and sediments creates ongoing exposure for marine organisms and contributes to broader environmental contamination. While environmental impacts are assessed separately from human health, these findings contribute to overall environmental loading and raise concerns about indirect exposure pathways, although human health implications of environmental presence remain uncertain.

A reassessment process is now underway

In response to these converging lines of evidence, a formal regulatory submission has been made in Australia requesting reassessment of octocrylene’s permitted use in therapeutic sunscreens. The submission incorporates human absorption data, Australian exposure modelling, degradation and impurity analysis, and the framework set out in the TGA’s recent benzophenone consultation. The focus is on aligning regulatory limits with what can realistically be controlled and what current science supports.

Moving toward safer, effective sun protection

Effective sun protection does not depend on any single chemical filter. Well-formulated sunscreens based on non-nano zinc oxide already provide broad-spectrum UVA and UVB protection with high photostability and negligible systemic absorption through intact skin. The current review process is aimed at ensuring that sunscreen regulation reflects modern evidence, manages degradation-related risks, and continues to protect public health without compromising sun safety.

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About the Australian Sunscreen Council

The Australian Sunscreen Council (ASC) is dedicated to protecting public health by championing the highest standards in sunscreen safety, testing, use and transparency.

Our mission is to ensure that all sunscreen and related products available to Australians meet or exceed the latest scientific evidence on ultraviolet (UV) protection and human health.

We promote balanced, evidence-based sun safety guidance, recognising that sunscreen is only a small part of the overall picture when it comes to sun safety and health. Our approach is holistic: effective UV protection includes shade, clothing, behaviour, and thoughtful timing of exposure—not sunscreen alone.

The ASC also supports greater public awareness of the documented benefits of moderate sun exposure, including vitamin D synthesis, improved mental wellbeing, and nitric oxide release—a process linked to healthier cardiovascular function and improved blood pressure regulation. We believe Australians deserve clear, science-backed advice that helps them understand how to obtain these benefits safely.

The ASC works collaboratively with government agencies, dermatologists, and public health experts to improve sunscreen standards and to support balanced, science-driven sun safety advice for all Australians.

Learn more at www.australiansunscreencouncil.org