Researchers from the University of Michigan reviewed of 27 studies conducted over the space of 26 years, and reported that soaps containing triclosan - the main antibacterial ingredient - within the range of concentrations commonly used in the community setting were no more effective than plain soaps.
"What it means for consumers is that we need to be aware of what's in the products. The soaps containing triclosan used in the community setting are no more effective than plain soap at preventing infectious illness symptoms, as well as reducing bacteria on the hands," stated lead researcher Allison Aiello from the university's School of Public Health.
A Freedonia Group market report showed that the demand for anti-bacterial ingredients for products such as soaps has risen steadily in recent years on the back of campaigns to increase health and hygiene awareness.
The report says that demand for such chemicals is set to rise 5 per cent annually to reach a market value of $930 million by 2009.
Behind the rising demand, a debate over whether antibacterial products offer benefits over plain soap has raged for over 30 years, with the industry defending the efficacy of the products, often claiming categorical evidence exists to prove that antibacterial soaps are more effective at keeping germs at bay.
But this is set to be challenged with the new review, published in the August edition of Clinical Infectious Diseases. The researchers looked at studies published between 1980 and 2006, and found that soaps containing triclosan within the range 0.1 to 0.45 percent weight per volume were no more effective than plain soaps.
Triclosan works by targeting a biochemical pathway in the bacteria that allows the bacteria to keep its cell wall intact. Because of the way triclosan kills the bacteria, mutations can happen at the targeted site. The researchers say that mutation could mean that the triclosan can no longer get to the target site to kill the bacteria because the bacteria and the pathway have changed form.
In hospital and other clinical settings, triclosan is used in higher, and may be more effective at reducing illness and bacteria.
"The lack of an additional health benefit associated with the use of triclosan-containing consumer soaps over regular soap, coupled with laboratory data demonstrating a potential risk of selecting for drug resistance, warrants further evaluation by governmental regulators regarding antibacterial product claims and advertising," concluded Aiello.
"Further studies of this issue are encouraged."
Other antiseptic products on the market contain different active ingredients, such as the alcohol in hand sanitizers or the bleach in some antibacterial household cleaners. The Michigan researchers did not study those products and those ingredients are not at issue.
No-one from the trade associations, The Cosmetics Toiletry and Fragrance Association and the Soap and Detergent Association, was available for comment prior to publication, but the associations were quick to comment when similar statements were made in 2005.
"More than thirty years of research has proven that antibacterial products reduce or eliminate bacterial that can lead to commonly transmitted disease. As our presentation to the FDA demonstrated, these products play an invaluable role in the everyday lives of consumers," the two industry associations said in a joint statement.
The industry associations went on to say that, although the laboratory studies had speculated over a link between antimicrobial products and bacterial resistance, there was no categorical evidence to prove this.
"At the heart of this discussion is the fact that every day, people face great potential for the transmission of harmful bacteria to themselves or others. Antibacterial products are proven to control the risks associated with exposure to potentially pathogenic organisms, providing consumers with a valuable extra measure of protection," the joint-statement said.
Source: Clinical Infectious Diseases
2007, Volume 45, Pages S137-S147
"Consumer Antibacterial Soaps: Effective or Just Risky?"
Authors: A.E. Aiello, E.L. Larson, and S.B. Levy