Science Thursday: Nano-particles in Cosmetics and Sunscreen
The use of nano-particles is becoming extremely widespread in in cosmetics, skin-care products and sunscreens. But what are nano-particles, and more importantly, are they safe?
First of all, if you are not familiar with the term “nano-particles,” you are in good company. According to Consumer Reports (July 2007), more than 80 percent of Americans have heard little or nothing about nanotechnology. This is probably due to the fact that manufacturers are not required to disclose the presence of nano-particles on their labels.
Nanoparticles are small particles either reduced from standard materials or created as new fabrications. They are about 100,000 times smaller than the width of a human hair and are currently used in everything from medicine to housepaint to cosmetics.
Unfortunately, only a tiny percentage (perhaps a nano-percentage?) of the nanotech research funding is being used to explore the risks of nanotechnology. This is troubling, because several worrisome findings from the limited laboratory and animal research so far indicate the following:
- Certain benign materials can become toxic when nanosized because microscopic particles tend to react more readily with human tissues and other substances.
- Nanoparticles can enter the body and its vital organs, including the brain, much more easily than can larger particles. And some are now used in food additives, cosmetics, and other products that are ingested or applied directly to the skin.
- Some nanomaterials seem to linger in the environment — especially in the water supply, where studies suggest they can damage the ecosystem.
- Fullerenes, composed of spherically arranged carbon atoms used in cosmetics and other products, might damage cells in fish, and harm human liver cells and DNA.
(from Consumer Reports.org).
With cosmetics and sunscreen, the main concern is the potential absorption of the nano-particles through the skin and into the bloodstream. Once in the blood, nanoparticles can be carried to cells throughout the body. Nanoparticles are able to enter the body and its vital organs, including the brain, much more easily than larger particles can.
This is problematic, because the smaller the particle, the more atoms there are on its surface as opposed to being tucked away inside. Increased number of surface atoms leads to greater reactivity with other compounds. This means that elements that may normally benign substances might become toxic when nano-sized. Further, particles that are known to be harmful at regular size can become even more dangerous as nanoparticles.
And, perhaps most alarming of all, the Food and Drug Administration is not required to review the safety of cosmetic ingredients before they are sold. The cosmetic industry’s Cosmetic Ingredient Review Board has not even evaluated the safety of nanoingredients.
So what are we to do? First of all, we can check labels for the few products that actually mention the presence of nano-particles. Some suncreens and skincare products do list the use of nano-ingredients. A list of 470 products labeled as containing nano-ingredients can be seen at the Wilson Center’s Project on Emerging Nanotechnologies website.
Other helpful websites include:
- Consumer Reports.org
- NPR article: Safety of Nano-Cosmetics Questioned
- International Council on Nanotechnology (ICON)
And finally, here is a link to a June 15, 2007 National Public Radio podcast on Talk of the Nation/Science Friday, hosted by Ira Flatow “The Science of the Very Very Very Small.
For now, the best we can do is try to stay informed and make good choices based on the knowledge we do have.
