European Commission Committee Opinion on Colloidal Silver (nano) (Report)

The Policy

What it does

Analyzes safety of cosmetic products containing colloidal silver and recommends additional data needed to understand risks.

Synopsis

The Scientific Committee on Consumer Safety (SCCS) released its final Opinion on Colloidal Silver (nano) at the request of the European Commission to assess the safety of nano-sized colloidal silver in cosmetics. This opinion outlines the relevant chemical, physical, and toxicological data of nano-colloidal silver, or nanosilver, needed to conduct a risk assessment. It focuses on nanosilver in dermal and oral cosmetic products, namely toothpaste and skin care products, and the corresponding potential exposure routes. Data submitted by 12 cosmetics manufacturers who use nanosilver is analyzed, and data gaps barring a complete risk assessment are identified. Based on the limited data provided, the SCCS concluded that insufficient data on nanosilver properties and toxicology in cosmetics exists to draw a conclusion.

The opinion outlines the nanosilver data submitted by the applicants in the following categories:

  • Chemical and physical specifications
  • Function and uses
  • Toxicological evaluation
  • Exposure assessment
  • Safety evaluation

The opinion assesses both the completeness and quality of data submitted by the applicants. It outlines each of the chemical and physical specifications (e.g. particle size, solubility, and surface properties) necessary to fully characterize each cosmetics product containing nanosilver. The SCCS concludes the data submitted is either incomplete or incorrect for each specification. In several cases, the data collection did not follow the previous SCCS Guidance on Safety Assessment of Nanomaterials in Cosmetics. The SCCS recommends particular experimental methods to measure some properties, including surface characteristics, in response to conflicting or incomplete data.

The SCCS outlines the various toxicological considerations associated with nanosilver in cosmetics, including carcinogenicity, irritation, and skin sensitization. The relevant pathways of exposure are also highlighted, namely oral and dermal toxicity. The opinion specifies the data needed to complete a full hazard assessment and the need to use representative materials when conducting those studies. Nanomaterials with different chemistries (e.g. size, shape, surface) often exhibit drastically different properties. Therefore, the SCCS advises that toxicological data be considered for each specific nanosilver formulation to ensure risks are properly identified.

Context

Nanomaterials are defined by the Commission as artificial materials that are insoluble or biopersistent where at least one internal or external dimension is between 1 and 100 nm. Nanomaterials are becoming increasingly prevalent in cosmetics products, in addition to numerous other consumer industries, because of their colorant, preservative, and UV-filtering properties. Nanomaterials can provide value such as improved skin hydration or transparency of a cosmetic. The E.U. is aware of 25 types of nanomaterials used in cosmetics products ranging from toothpaste to lipstick to shampoo.  

The emergence of this new class of materials and the repeated exposure possible with cosmetics products has resulted in regulatory agencies rushing to assess risks and develop policies focused on cosmetics. In the 2007 Opinion on Safety of Nanomaterials in Cosmetic Products, the SCCS assessed the viability of existing hazard identification methods on nanomaterials and the additional measures necessary for this class of materials. The Cosmetics Regulation of 2009 requires cosmetics manufacturers to disclose and label all nanomaterials and subjects them to further risk assessment by the SCCS. The SCCS then released a Guidance on the Safety Assessment of Nanomaterials in Cosmetics in 2012 that outlines information manufacturers should provide for a complete risk assessment in compliance with the Cosmetics Regulation.

In the U.S., the Food and Drug Administration (FDA) is responsible for regulating cosmetics. Unlike the E.U., the FDA has not yet imposed specific requirements, regarding labeling or disclosure, on cosmetics containing nanomaterials. Under the U.S. Federal Food, Drug, and Cosmetic Act, cosmetic products are not subject to premarket approval by the FDA unless they contain color additives. Therefore, the FDA cannot conduct testing of a nanomaterial’s properties or require safety information from the manufacturer. The use of certain ingredients, such as mercury, is restricted or prohibited; however, none of these regulated ingredients are specifically nanomaterials.

In June 2014, the FDA released their Guidance for Industry: Safety of Nanomaterials in Cosmetic Products detailing factors for cosmetics manufacturers to consider and assess when determining the safety of nanomaterials. Further, it encouraged manufacturers interested in using nanomaterial ingredients in cosmetics to meet with the FDA to discuss testing methods. However, all disclosure of nanomaterial use to the FDA is still voluntary. This differs notably from the disclosure and labeling requirements of nanomaterials in cosmetics mandated by the Cosmetics Regulation in the E.U.

The Opinion on Colloidal Silver (nano) was initiated in response to 63 notifications of nano-sized colloidal silver ingredients in cosmetics products. The Commission had minimal information on the properties and safety of colloidal silver in nano form before requesting the opinion. Following a call for safety data of colloidal silver in 2015, the Commission received scientific data from 12 applicants and requested the SCCS conduct a full risk assessment of nanosilver use in cosmetics. Colloidal silver refers to silver particles suspended in solution. The opinion focuses exclusively on colloidal silver in nano form.

Nanosilver is particularly noted for its antimicrobial properties, making it useful in cosmetic products including deodorant and toothpaste. This prevalence has caused concern among global regulatory agencies because the health hazards of nanosilver exposure are largely unknown. The European Commission released their Opinion on Nanosilver: safety, health and environmental effects and role in antimicrobial resistance in 2014 on the status of known nanosilver health concerns and exposure routes. While the U.S. has no regulations or recommendations specific to nanosilver use in cosmetics, the Environmental Protection Agency recently released their Nanosilver Final Work Plan (SciPol brief available) regarding nanosilver in pesticides and information needed to fully assess its risks.

The Science

Science Synopsis

Unique properties emerge when materials are confined to nanoscale dimensions which fundamentally differ from bulk materials. Nanosilver introduces a particularly wide array of new or enhanced properties compared to traditional silver. The impressive antimicrobial effects of nanosilver have spurred companies to use it in a variety of consumer products to combat microorganisms. Manufacturers have so far focused on utilizing the antimicrobial properties of nanosilver, but this nanomaterial also demonstrates promise for biomedical applications and optical technologies that may be commercially available in the future.

The specific characteristics of a nanomaterial – such as size, shape, and surface chemistry – largely determine its properties and interactions with other materials, and nanosilver is no exception. Researchers have demonstrated how the shape of nanosilver can affect toxicity. Surface chemistry is a particularly critical characteristic that can alter properties such as charge, reactivity, water solubility, and compatibility in the body. Scientists engineer surface chemistry by attaching one of a host of possible molecules, called ligands, to the surface of nanosilver particles to alter properties. These properties are critical when determining the hazards posed by nanosilver. Therefore, the Opinion on Colloidal Silver (nano) advises the specific chemical and physical properties of each colloidal silver product be disclosed. Further, it advises that toxicological data be provided for particular formulations of colloidal nanosilver.

Cosmetics consumers are particularly susceptible to colloidal nanosilver exposure due to the nature of systemic use of cosmetic products. Dermal exposure is the largest possible exposure route for most cosmetics, such as sunscreen, moisturizer, and makeup. This exposure route enables the potential for nanosilver to penetrate the skin, particularly damaged skin, and potentially migrate to various target organs. Repeated application of these everyday cosmetics further increases the risk of nanosilver exposure through skin and its impacts. Oral exposure is also possible with toothpaste and mouthwash products containing nanosilver.

Scientific Assumptions

Silver particles exposed to water will create ionic silver (Section 3.1.1.2.): A large body of scientific literature agrees that exposure of nanosilver to water causes a reaction that releases silver ions.

 

Acute toxicity differs based on specific nanosilver particle properties (Section 3.3.1.): It is generally agreed upon that nanosilver properties, particularly size and shape, can affect toxicity, notably via both oral and dermal exposure routes.


The Debate

Scientific Controversies / Uncertainties

A concern with any antibacterial agent, such as nanosilver, is the development of bacterial resistance. This is a concern particularly because of the pervasiveness of nanosilver as a preventative antibacterial agent in so many everyday commercial products, which might decrease their potency in killing bacteria. Some microorganisms have already demonstrated bacterial resistance to nanosilver, but the full extent of these effects and the associated resistance mechanisms have not be fully studied.

Long-term effects of nanosilver on humans are similarly unknown. Studies have reported uptake of silver nanoparticles in multiple organs, including the spleen, kidneys, and even brain. Absorption into the body and even specific organs might not inherently be cause for concern, but the long-term risks and toxicity of this absorption has not been conclusively determined. In many cases, proper methodology has not yet been developed to thoroughly assess human exposure risk to nanomaterials such as nanosilver.

Potential Impacts

This Opinion made it clear that more data is needed to assess the risks of nanosilver in cosmetics. It is possible that this policy will spur additional data collection on health impacts, either voluntarily by manufacturers or through a second call for data on colloidal nanosilver under the Cosmetics Regulation. If evidence surfaces showing nanosilver is potentially hazardous to human health, stricter regulations will likely be imposed on its use in cosmetics.