Adelaide (Australia), Jul 16 (The Conversation) The Therapeutic Goods Administration (TGA) in Australia has recently published a safety review concerning seven active ingredients frequently used in sunscreens. Five of these ingredients were deemed low-risk and suitable for use at their present concentrations.
However, the TGA has suggested stricter regulations on two ingredients – homosalate and oxybenzone. This recommendation stems from uncertainties around their potential effects on the endocrine system, which regulates hormone production and release.
These findings, coupled with reports of products overstating their SPF claims, may cause Australians to question the efficacy and safety of their sunscreen products. Nonetheless, abandoning sunscreen is not advisable. In Australia, sunscreens undergo rigorous approval processes before hitting the market. These products are assessed for safety and efficacy, and the latest review reflects the TGA's commitment to safety standards.
The most significant risk associated with sunscreen for the health of Australians is failing to use it. Australia has the highest rates of melanoma and non-melanoma skin cancer globally, with approximately 95% of melanoma cases in Australia linked to ultraviolet (UV) exposure.
Understanding product ingredients is important to consumers, so let's delve into the details of the safety review.
Active Ingredients in Sunscreen There are two primary types of sunscreen: physical and chemical. This differentiation is based on the active ingredients they contain.
An active ingredient is any chemical component in a product that imparts a specific effect on the body—essentially, what makes the product "work." In sunscreens, these compounds absorb UV rays from the Sun, while other ingredients, like those providing fragrance or aiding skin absorption, remain "inactive."
Physical sunscreens generally use minerals like titanium dioxide and zinc oxide, which can absorb and reflect some sunlight. Chemical sunscreens employ a range of chemical ingredients to absorb or scatter both UVA and UVB light.
The TGA's review focused on seven active ingredients prevalent in chemical sunscreens.
Why the TGA Conducted This Review The concentration limits for these chemicals in sunscreen typically align with other regulatory bodies like the European Union and the US Food and Drug Administration. However, safety is an evolving field, prompting the TGA to periodically reassess all therapeutic goods.
Last year, the TGA updated its approach to estimating sunscreen exposure to better reflect real-world usage patterns. This model accounts for the amount of sunscreen applied, the extent of skin coverage, and how the skin absorbs it.
In conjunction with evolving EU and US regulatory practices, the TGA embarked on a detailed examination of seven widely used sunscreen ingredients.
Determining Safety In assessing chemical safety for human use, studies often include animal testing, particularly in the absence of comprehensive human data. These tests are usually conducted by manufacturers rather than the TGA.
A "margin of safety" is incorporated to account for potential human sensitivities to these chemicals, typically calculated at concentrations 50–100 times lower than the dose at which no negative effects are observed in animals.
For the sunscreen review, a safety threshold was set 100 times lower than this no-effect dose. Most of the examined chemicals met this margin, indicating they are safe and present low risk for long-term use.
However, homosalate and oxybenzone did not meet this threshold when applied to the body at maximum permissible concentrations: 15% for homosalate and 10% for oxybenzone. Nonetheless, lower concentrations, such as those used for face and hands, were considered low-risk.
Potential Health Concerns Homosalate and oxybenzone exhibit low acute oral toxicity, meaning one would need to ingest substantial quantities to experience toxicity. Additionally, they do not irritate the eyes or skin.
There is inconclusive evidence linking oxybenzone to cancer in animal studies, but only at exposure levels far above those associated with sunscreen use.
The primary concern pertains to potential effects on the endocrine system. Although animal studies have indicated effects at high concentrations, the relevance of these findings to human exposure levels remains unclear.
Clinical studies have detected no effects on fertility, hormones, weight gain, or fetal development in pregnant women. The TGA adopts a cautious approach, incorporating a substantial margin of safety even in worst-case scenarios.
Recommendations The TGA proposes reducing the allowed concentrations of homosalate and oxybenzone. The specific reductions depend on factors such as target demographics (adults or children) and intended use (face or whole body). Some sunscreen formulas may require reformulation or revised labeling. Public consultations will shape the final decisions, with submissions closing on August 12.
Benzophenone Concerns Some evidence suggests that benzophenone, a byproduct of octocrylene degradation in sunscreen, could be carcinogenic at high concentrations. This conclusion is drawn from studies involving mice and rats exposed to benzophenone levels exceeding those present in sunscreen.
Octocrylene degrades into benzophenone over time, with higher temperatures accelerating the process. Accordingly, the TGA has recommended restricting benzophenone content to 0.0383% in sunscreens to ensure safety over the product's shelf life. The Cancer Council advises storing sunscreens at temperatures below 30°C.
The Bottom Line The suggested restrictions are highly conservative, based on worst-case scenarios. Yet, even under such conditions, the safety margins remain below levels at which negative effects were observed in animals.
The risk of skin cancer from sun exposure is far more pressing than any potential adverse effects from sunscreens. For those seeking alternatives, several sunscreens offer high protection with minimal or no homosalate and oxybenzone. Consumers should review product labels for more information.
(Only the headline of this report may have been reworked by Editorji; the rest of the content is auto-generated from a syndicated feed.)
