Sunscreens protect skin from the sun’s harmful ultraviolet (UV) radiation. Oxybenzone, also known as benzophenone-3, has been a common active ingredient in many sunscreen formulations. Its use in sun protection products is now a subject of discussion and scientific inquiry due to evolving understandings of its broader impacts.
Understanding Oxybenzone and Its Purpose
Oxybenzone functions as an organic, or chemical, UV filter. Its role is to absorb ultraviolet A (UVA) and ultraviolet B (UVB) rays, preventing skin damage. This absorption transforms UV radiation into a small amount of heat, which then dissipates from the skin.
For decades, oxybenzone has been a popular sunscreen ingredient. It offers effective broad-spectrum protection, guarding against sunburn and long-term skin damage. Its ease of incorporation into cosmetic formulations also contributed to its widespread use.
Potential Human Health Concerns
Research indicates that oxybenzone can be absorbed through the skin and enter the bloodstream. Studies have detected the compound in various bodily fluids, including urine, blood plasma, and breast milk. The extent of this absorption can vary depending on the product formulation and application frequency.
Concerns exist regarding oxybenzone’s potential as an endocrine disruptor, meaning it might interfere with the body’s hormone systems. Some in vitro (test tube) and animal studies have suggested that oxybenzone can exhibit estrogenic activity or affect thyroid hormone levels. However, the relevance of these findings to human health at typical exposure levels is still under investigation, and human studies have yielded varied results.
For some individuals, oxybenzone can cause allergic reactions, leading to skin sensitization. This may manifest as contact dermatitis, characterized by redness, itching, or swelling. Photoallergic contact dermatitis is another potential side effect, occurring only after skin exposure to both oxybenzone and sunlight.
Environmental Concerns
Oxybenzone’s impact on aquatic ecosystems, particularly coral reefs, is an environmental concern. When individuals swim after applying sunscreen, or wastewater enters marine environments, oxybenzone can be released into the water. This chemical has been detected in oceans, lakes, and rivers globally.
Scientific studies have demonstrated that oxybenzone contributes to coral bleaching, a process where corals expel the algae living in their tissues, leading to their demise. It can also cause DNA damage in coral larvae and disrupt their reproductive cycles and development. Even at low concentrations, oxybenzone has shown detrimental effects on coral health and resilience.
Beyond corals, oxybenzone has been observed to affect other marine organisms. It can impact the reproductive success and development of various marine invertebrates, such as sea urchins. Fish exposed to oxybenzone have shown altered behaviors and potential endocrine disruption, indicating a broader toxicological effect across the marine food web. The compound’s persistence in water environments further classifies it as an environmental contaminant.
Alternatives and Regulatory Landscape
Consumers seeking alternatives to sunscreens containing oxybenzone often turn to mineral sunscreens. These products use zinc oxide and titanium dioxide as active ingredients, which create a physical barrier on the skin that reflects UV rays. These mineral filters are considered safe for both human health and aquatic environments, as they are less likely to be absorbed into the body or cause coral damage.
Some sunscreens are marketed as “reef-safe,” indicating they are formulated without ingredients known to harm coral reefs, such as oxybenzone and octinoxate. When selecting a product, consumers should examine the ingredient list to confirm the absence of these chemicals. Many brands now offer formulations that prioritize environmental compatibility.
Due to growing environmental concerns, several regions and countries have implemented regulations restricting or banning sunscreens containing oxybenzone. Hawaii, for example, banned the sale and distribution of sunscreens containing oxybenzone and octinoxate, effective January 1, 2021, to protect its coral reefs. Similar restrictions have been implemented in areas like Palau, the U.S. Virgin Islands, and parts of Mexico, reflecting a global shift toward environmentally conscious sunscreen choices.