There is a health risk from nanoparticles in sunscreens
the verdict
INSUFFICIENT LEANING
refutedsupported
the weight of evidence
6 sources for · 0 against
Scientific literature presents a nuanced view, noting that while dermal absorption of sunscreen nanoparticles is generally low or non-toxic in vivo, potential risks exist regarding cellular cytotoxicity, inhalation from sprays, and non-degradable accumulation.
Narelle Brown, a pregnant mother of two children, purchases a sunscreen product for her children prior to taking them for their annual summer holiday at the beach. One of her children, a 10-year-old girl, has eczema and the other, an 8-year-old boy, is always cutting himself in his games. Both children will spend long periods in the sun on the holidays, requiring repeated applications of sunscreen. Narelle notices that on the pack, the sunscreen is described as “microfine.” There are instructions, but no warnings about its use. Narelle takes her family on the holiday and uses the sunscreen repeatedly, including on herself. During the stay she meets a couple from next door, both of whomwork for the Australian Therapeutic Goods Administration (TGA). They notice her sunscreen and tell her that it contains titanium dioxide (TiO2) and zinc oxide (ZnO) in nanoparticulate form. They tell her that in 2006, of the 1,200 sunscreens authorised by the TGA, most (70%) contained these insoluble metal oxide particles in a nanoscale form. They say that when reduced to nanoscale dimensions, TiO2 and ZnO become increasingly translucent, which provides sunscreens’ greater transparency when applied to the skin. Narelle asks if any health risks are associated with using nanoparticles in sunscreens for herself or her children. She also has friends in London who are now using sunscreen regularly because of global warming. The neighbours say that the evidence is equivocal. There may be some cellular
Nanotechnology represents an important complement to traditional chromophore-based UV filters. Nanosized metal oxides are widely used due to their broad protection spectrum and reduced skin irritation. These particles are already present in most commercial sunscreen lotions even though their photoreactivity has been highlighted as a potential cause of cytotoxic effects in human skin cells (e.g. fibroblasts, epithelial cells). However, this cytotoxicity is not likely to represent a significant health risk to consumers as several skin penetration assays have shown that the photoreactive particles penetrate at most to the stratum spinosum of the epidermis. Nanoencapsulation of traditional organic UV filters is a more recent approach to improve skin retention, photostability and the UV blocking ability of the free molecules. All of these improvements have been confirmed with different scientific assays for different particles, especially polymeric nanocapsules and solid lipid nanoparticles. These technological advantages offered by nanometric particles for sun protection formulations have made them commercially important. In inventories from non-governmental organizations there are approximately 30 commercial sunscreen products listed as containing nanoparticles.
Excessive ultraviolet (UV) radiation increases skin disease risk, which is a global health issue. Sunscreen is an effective way to reduce UV radiation. While inorganic nano ZnO and TiO2 have occupied partial sunscreen market in recent years due to their high efficiency and good photostability, there is still improvement space in sunscreen efficiency, biological safety and customization. This paper reviews the recent literature on inorganic nano sunscreen modification. To improve sunscreen performance, the inorganic nanoparticles can be loaded on scaffold materials or doped with specific metal elements. For their biological safety, modification with certain natural polymers to eliminate reactive oxygen species (ROS) and the size/structure control to decrease skin penetration are effective. Adding dark-colored materials and skin-care materials to inorganic nano sunscreen formulations helps them better commercialization. However, most of these studies are still in the laboratory stage, requiring further research. Hopefully, more enhancement mechanisms and available modification materials are expected to be developed in the future.
Summary Photoprotection has become integral in the prevention of keratinocyte cancer and photoaging. Organic ultraviolet ( UV ) filters such as oxybenzone and octinoxate have become controversial due to their potential impact on the environmental and their potential human health risks. As such, inorganic UV filters, zinc oxide (ZnO) and titanium dioxide (TiO 2 ) , have become paramount in discussions about photoprotection. ZnO and TiO 2 are used in sunscreens as nanoparticles, which denotes a size <100 nm. The smaller size of these mineral particles increases their cosmetic acceptability by users as they are much less visible after application. ZnO has a broad UVA ‐ UVB absorption curve, while TiO 2 provides better UVB protection. Overall, the human health risks with inorganic filters are extremely low given a lack of percutaneous absorption; however, there is potential risk when exposed via inhalation, prompting recommendations against spray sunscreen products with nanoparticles. At this time, the known risk to the environment is low though the risk stratification may evolve with increasing usage of these filters and higher environmental concentrations. The continued practice of photoprotection is critical. The public should be counseled to seek shade, use photoprotective clothing including hats and glasses in addition to sunscreens on sun‐exposed skin. For those concerned about emerging evidence of environmental impact of organic UV filters, based on current evidence, ZnO a
This decade has seen revolutionary developments in the field of nanotechnology with newer and diverse applications of nanoparticles (NPs) appearing every day. However, there are limited data about the toxicity of nanoparticles and their fate in biological systems. Inhalation, ingestion, and dermal penetration are the potential exposure routes for nanoparticles, whereas particle size, shape, surface area, and surface chemistry collectively define the toxicity of nanoparticles. Increased production and intentional (sunscreens, drug delivery) or unintentional (environmental, occupational) exposure to nanoparticles are likely to increase the possibilities of their adverse health effects. It is crucially important that novel nanomaterials must be biologically characterized for their health hazards to ensure risk-free and sustainable implementation of nanotechnology.
Like other sectors, the cosmetics industry resorts to developments in the field of nanotechnologies. Encapsulation and carrier systems like liposomes, nanoemulsions, microemulsions or lipid nanoparticles serve to transport agents to deeper skin layers. Nano particles of titan dioxide and zinc oxide are used as UV filters in sunscreens. According to the producers, cosmetic products with nano minerals, nano-scaled gold and silver or fullerenes can be found on the market. While, according to our present state of knowledge, soluble or degradable nano materials are not considered critical for health, there are as yet no unambiguous results for the assessment of the potential toxic effects on humans and the ecosystem of non-soluble or non-degradable nano materials. Some studies, however, give hints of potential negative health effects. This needs to be studied in more detail within the framework of a comprehensive risk assessment – as insisted on by, among others, the EU Scientific Committee on Consumer Products (SCCP) and a number of environmental and consumer organisations.
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