What are the genotoxic effects of sunscreens?

From the Guidelines

The use of sunscreens with mineral-based ingredients, such as non-nano zinc oxide or titanium dioxide, is recommended due to their lower genotoxic potential compared to chemical filters. When considering the genotoxic effects of sunscreen, it's essential to weigh the potential risks against the known benefits of sun protection. Chemical filters like oxybenzone, octinoxate, and octocrylene have shown evidence of DNA damage in laboratory studies, particularly when exposed to UV radiation 1. However, the real-world significance of this genotoxicity for humans using sunscreen normally remains unclear.

Key Considerations

• The genotoxic potential of sunscreen ingredients appears higher when exposed to UV light, which can transform relatively harmless compounds into more reactive species.
• Mineral-based sunscreens containing non-nano zinc oxide or titanium dioxide generally show lower genotoxic potential than chemical filters.
• The potential DNA damage from sunscreen should be weighed against the known DNA damage and cancer risk from unprotected sun exposure, which is substantially greater.

Recommendations

• Use sunscreens with mineral-based ingredients, such as non-nano zinc oxide or titanium dioxide, to minimize genotoxic potential.
• Apply sunscreen as directed, with a sun protection factor (SPF) of 15 or greater, to protect against UV A and UV B radiation and reduce the risk of skin cancer and early skin aging 1.
• Consider the importance of sun protection in preventing skin cancer, as recommended by various health organizations, including the American Cancer Society and the American Academy of Dermatology 1.

From the Research

Genotoxic Effects of Sunscreen

• The genotoxic effects of sunscreen are not directly mentioned in the provided studies, however, some studies discuss the potential health risks associated with certain sunscreen ingredients 2, 3.
• Oxybenzone, a common sunscreen ingredient, has been reported to produce contact and photocontact allergy reactions, and has been linked to Hirschsprung's disease 2.
• Additionally, oxybenzone has been shown to react with chlorine, producing hazardous by-products that can concentrate in swimming pools and wastewater treatment plants 2.
• Inorganic UV filters, such as zinc oxide and titanium dioxide, have been found to have extremely low human health risks due to a lack of percutaneous absorption, but there is potential risk when exposed via inhalation 3.
• The photolysis of organic UV filters, such as avobenzone, can be increased by the presence of titanium dioxide nano composites, which can potentially lead to the formation of toxic by-products 4.

Safety of Sunscreen Ingredients

• The safety of sunscreen ingredients is a topic of ongoing debate, with some studies suggesting that certain ingredients, such as oxybenzone, may pose health risks 2.
• Other studies have found that inorganic UV filters, such as zinc oxide and titanium dioxide, are safe alternatives to organic UV filters 3.
• The use of proper formulation strategies can help minimize the loss of avobenzone, a common sunscreen ingredient, and ensure that it remains effective in providing broad-spectrum protection 5.

Environmental Impact of Sunscreen

• The environmental impact of sunscreen is also a concern, with some studies suggesting that certain ingredients, such as oxybenzone, can cause toxic reactions in coral and fish 2.
• The use of inorganic UV filters, such as zinc oxide and titanium dioxide, may have a lower environmental impact than organic UV filters, but more research is needed to fully understand their effects 3.