Oxybenzone in Sunscreens: When Legacy Approval Meets Modern Evidence

A widely used UV filter shaped by earlier regulatory assumptions

Oxybenzone, also known as benzophenone-3, has been used in sunscreen products for decades due to its effectiveness in absorbing UVB and short-wave UVA radiation. Its approval dates back to a period when sunscreen regulation focused primarily on UV efficacy and short-term toxicity. Like several long-standing sunscreen ingredients, oxybenzone remains permitted today largely because it was accepted under legacy regulatory frameworks that did not require the breadth of systemic exposure, endocrine, and cumulative-use data now considered standard.

What legacy approvals did not evaluate

At the time oxybenzone entered regulatory use, human maximal-use pharmacokinetic studies were not required, and repeated whole-body application under real-world conditions was not systematically assessed. Safety evaluations relied on oral animal studies, limited dermal testing, and assumptions that topical application would result in minimal internal exposure. Potential endocrine activity, developmental sensitivity, and aggregate exposure from multiple products were not central considerations in early assessments.

Systemic absorption is now clearly established

Human studies have since demonstrated that oxybenzone is readily absorbed through the skin and enters systemic circulation following routine sunscreen use. Detectable levels have been measured in blood and urine after repeated application, with persistence for several days after use stops. Importantly, the detection of oxybenzone in systemic circulation shifts the regulatory question away from acute toxicity and toward the adequacy of existing safety assumptions for chronic, repeated exposure, particularly for substances with endocrine activity where traditional dose–response thresholds may not be protective. Nevertheless, once systemic exposure is established, safety assessments based solely on topical exposure assumptions are no longer sufficient to meet modern evidence expectations.

Endocrine activity complicates traditional risk assessment

Experimental studies have demonstrated that oxybenzone interacts with estrogenic and anti-androgenic pathways in laboratory and animal models. While direct causality in humans has not been established, this absence of definitive human data reflects the limitations of legacy testing frameworks rather than evidence of safety. For substances that are systemically absorbed and biologically active at low concentrations, uncertainty itself becomes a regulatory concern. Modern endocrine risk assessment recognises that hormonal effects may occur at exposure levels below those that trigger overt toxicity, and that reliance on traditional thresholds can fail to capture biologically relevant effects under chronic, real-world use conditions.

Why Australian use patterns matter

Australia represents a high-exposure context for sunscreen ingredients. Public health guidance encourages frequent, generous application over large body surface areas, often multiple times per day. When these real-world use patterns are incorporated into exposure modelling, estimated systemic doses of oxybenzone increase relative to assumptions used in many historical assessments. In its July 2025 safety review, the Therapeutic Goods Administration identified that, under high-use scenarios modelled using the Australian Sunscreen Exposure Model, margins of safety for oxybenzone can fall below preferred thresholds. This finding prompted the recommendation of precautionary concentration restrictions, with public consultation ongoing into 2026.

Environmental considerations broaden the discussion

Beyond human health, oxybenzone has been detected in marine and freshwater environments. Laboratory and some field studies have reported adverse effects in aquatic organisms, including coral bleaching and developmental toxicity in fish, under experimental or high-exposure conditions. While the ecological relevance of these findings at typical environmental concentrations remains under scientific debate, environmental concerns have driven restrictions on oxybenzone use in several jurisdictions. These considerations add to the overall assessment of an ingredient whose impacts extend beyond individual use.

Regulatory responses are evolving, not uniform

Regulatory approaches to oxybenzone now reflect differing interpretations of the same evidence base. Some jurisdictions have restricted its use in response to environmental concerns, while others continue to permit it for human use within defined concentration limits. In Australia, the current approach recognises both the benefits of sunscreen use and the need to manage uncertainty through precautionary controls rather than outright prohibition. This divergence reflects evolving regulatory standards rather than consensus that oxybenzone poses confirmed harm under all conditions of use.

What reassessment does and does not mean

Re-examining oxybenzone does not imply that sunscreen products are unsafe or that sun protection should be avoided. Sunscreen remains a critical tool for skin cancer prevention. Reassessment reflects the reality that ingredients approved decades ago were not evaluated against today’s scientific expectations for systemic exposure, endocrine activity, and cumulative use. Updating these assessments is a normal and necessary part of regulatory evolution.

Looking forward with modern alternatives

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

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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