Avobenzone in Sunscreens: When Legacy Approval Meets Modern Use

A widely used UVA filter shaped by historic assumptions

Avobenzone is one of the most important UVA filters used in sunscreens and has played a central role in improving broad spectrum protection worldwide. Its approval dates back to the late 1980s, a period when sunscreen regulation prioritised ultraviolet performance and short-term safety rather than systemic exposure, cumulative use, or long-term internal dose. Like many long-standing sunscreen actives, avobenzone remains permitted today largely because it was accepted under legacy regulatory frameworks that did not require the kinds of data now considered standard.

What legacy approval did and did not evaluate

At the time avobenzone entered regulatory use, human maximal use pharmacokinetic studies were not required. Regulators did not routinely assess internal exposure following repeated whole body application, nor did they require evaluation of degradation products formed during normal use. Safety assessments relied on oral animal studies, basic dermal testing, and assumptions that topical application would result in minimal systemic availability. These approaches reflected the scientific tools of the time, but they leave important questions unanswered under modern use conditions.

Systemic exposure changes the evidence expectations

Human maximal use studies have since demonstrated that avobenzone is absorbed through the skin and can be detected in systemic circulation following repeated application. Plasma concentrations observed in these studies exceeded the threshold used by regulators to trigger the need for additional safety data, and levels remained measurable for several days after last use. These findings do not demonstrate harm, but they do establish that avobenzone is systemically available rather than purely topical. Once systemic exposure is demonstrated under routine conditions, continued reliance on assumptions developed for surface limited exposure becomes increasingly difficult to justify without updated, use matched data.

Contextualising exposure and risk

Importantly, the systemic concentrations of avobenzone observed in human studies remain orders of magnitude below levels associated with toxicity in animal studies, and no adverse health effects have been linked to its use in sunscreens. This distinction matters. Absorption alone does not equal risk. However, the presence of measurable internal exposure shifts the scientific question from whether exposure occurs to whether existing data are sufficient to confirm safety under contemporary patterns of use.

Photodegradation adds complexity rather than certainty

Avobenzone is photolabile and can degrade into multiple byproducts when exposed to ultraviolet radiation unless stabilised by other formulation components. Modern sunscreens routinely address this through stabilisers and filter combinations, improving performance and durability. At the same time, the toxicological profiles of several degradation products remain incompletely characterised. This does not indicate demonstrated harm, but it contributes to uncertainty that was not fully considered at the time of original approval.

Why Australian use patterns matter

Australia represents a high exposure context for sunscreen ingredients. Public health guidance encourages frequent and generous application over large areas of skin, often multiple times per day. These patterns exceed those assumed in many historical safety assessments. When real world Australian use is considered, estimated systemic exposure increases relative to legacy models. In this setting, reliance on grandfathered approvals without contemporary, use matched confirmation of safety becomes a question of evidence currency rather than regulatory failure.

Different regulators, different conclusions

International regulatory approaches to avobenzone reflect genuine divergence rather than simple timing differences. In the United States, the Food and Drug Administration permits avobenzone but has stated that available data are insufficient to conclude that it is generally recognised as safe and effective under modern standards, citing systemic absorption. In contrast, the European Union continues to permit avobenzone at concentrations up to five percent based on updated assessments that incorporate newer absorption and photostability data. Australia currently aligns more closely with the European position. These differences reflect varying thresholds for uncertainty rather than consensus about long term systemic safety.

What reassessment actually means

Reassessing avobenzone does not imply that current sunscreen products are unsafe, nor does it undermine the importance of sunscreen in preventing skin cancer. Reassessment is a normal feature of regulatory systems when scientific expectations evolve. It reflects the reality that ingredients approved decades ago were never designed to meet today’s evidence standards for chronic, high frequency, whole body exposure. Grandfathered approval explains continued use, but it does not replace the need for modern confirmation.

Looking ahead with clarity and confidence

Effective sun protection does not depend on any single chemical UV filter. Well formulated sunscreens using non-nano zinc oxide provide stable, broad spectrum UVA and UVB protection with minimal systemic absorption through intact skin. Ensuring that widely used ingredients like avobenzone are evaluated against contemporary evidence expectations helps maintain public confidence in sunscreen products while supporting ongoing skin cancer prevention efforts.

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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