Assessing the Safety of Chemicals in Sunscreen: Insights from a Pharmacology Expert

Recently, the Therapeutic Goods Administration (TGA) conducted a comprehensive safety review of seven active ingredients commonly found in sunscreens. This review aimed to evaluate their long-term safety and determine whether current usage levels are appropriate. The findings indicated that five of these ingredients pose low risk when used at existing concentrations, aligning with safety standards set by other regulatory bodies like the EU and US FDA. However, the TGA advised tighter restrictions on homosalate and oxybenzone due to uncertainties regarding their potential endocrine-disrupting effects.

The review highlighted that both ingredients are considered low in toxicity, as they require ingestion of large amounts to cause toxicity and do not irritate skin or eyes. Nonetheless, animal studies have shown effects at high concentrations, raising questions about possible impacts on hormone systems in humans. Currently, clinical studies have not demonstrated any adverse effects on fertility, hormones, or pregnancy outcomes, but regulators remain cautious.

Sunscreens contain active ingredients that absorb UV radiation, protecting the skin from harmful effects like melanoma and non-melanoma skin cancers, which are prevalent in Australia due to high UV exposure. The review's purpose was to ensure these ingredients remain safe for consumers, considering the latest exposure models and safety thresholds.

The chemicals in question, primarily used in chemical sunscreens, include compounds like homosalate and oxybenzone that have raised safety concerns. While these chemicals exhibit low oral toxicity and do not cause irritation, their potential endocrine effects remain under investigation. The TGA proposed reducing their permitted concentrations and may require reformulation or warning labels pending public consultation.

Additionally, benzophenone, a degradation byproduct of sunscreens containing octocrylene, has been linked to potential carcinogenic effects at high levels in animal studies. The TGA recommends limiting its presence in sunscreens to ensure safety throughout the product's shelf life.

Overall, even under worst-case exposure scenarios, the margin of safety for these ingredients stays below levels associated with harmful effects observed in animals. The primary health risk remains the failure to use sunscreen, especially in sun-intense environments like Australia, where UV exposure is a leading cause of skin cancer. Consumers interested in avoiding certain chemicals can opt for products formulated without homosalate and oxybenzone, reading labels carefully. The TGA’s ongoing review highlights a cautious approach to sunscreen safety, maintaining protection while addressing potential risks.