Triclosan: Chemical In Toothpaste Linked To Cancer


Triclosan is an antibacterial chemical which is often used in shampoos, toothpastes and other household items. This chemical has been under heavy scrutiny by the American Food and Drug Administration (FDA) due to recent reports that linked it to hormone disruption and impaired muscle contraction.

Many UK manufacturers stopped using this chemical in household cleaning and sanitary products but it can still be found in Dial antibacterial liquid hand soap, Dermalogica Skin Purifying wipes and Colgate Total toothpaste.

Don’t brush it under the carpet

Now, in a new study, published in the journal Proceedings of the National Academy of Sciences, researchers say that long term exposure to Triclosan may be carcinogenic.

During the study researchers exposed mice to triclosan for six months – roughly the equivalent of 18 human years. The results showed that exposure to triclosan caused liver fibrosis – excess fibrous tissue in the liver – and cancer through molecular mechanisms which also apply in humans.

Commenting on the study, lead researcher, Dr. Robert Tukey, professor in the departments of Chemistry and Biochemistry and Pharmacology at University of California, said: “Triclosan’s increasing detection in environmental samples and its increasingly broad use in consumer products may overcome its moderate benefit and present a very real risk of liver toxicity for people.”

The study suggests triclosan may do its damage by interfering with the body’s ability to get rid of toxic chemicals. However the researchers pointed out that the dose of triclosan they tested was considerably higher than the average amount that humans might ingest from toothpaste and other products.

British experts said more research was needed to determine whether the effects seen in mice were also applicable to humans.

Dr Nick Plant, from the University of Surrey, said: “It is not valid to state that the effect of triclosan in mice will occur in humans as well, indeed the historical body of evidence suggests a species-dependent effect is more likely.”

While it may still take some time to get clarity around triclosan’s cancer risk, there are more than enough other reasons why this chemical should be avoided at all costs.

Triclosan has already been linked to endocrine disruption (the endocrine system secretes hormones directly into the circulatory system) and has been shown to impact thyroid function and thyroid homeostasis. A 2009 study found that triclosan decreased thyroid hormone concentrations and another study showed that triclosan enhanced the expression of androgen and oestrogen sensitive genes.

Triclosan targets bacteria in a similar way to antibiotics, which raises some concerns that bacteria that become resistant to triclosan will also become resistant to antibiotics. In fact, a 2010 report by the European Commission’s Scientific Committee on Consumer Safety determined that even low concentrations of triclosan can trigger antibiotic resistance in bacteria.

Triclosan is lipophilic, meaning that it accumulates in fatty tissues. Studies have found concentrations of triclosan in three out of five human milk samples. The chemical has also been found in the umbilical cord of infants, raising huge concerns for foetuses during vulnerable periods of development especially since this chemical can potentially disrupt the endocrine system.

The majority of the products that contain triclosan are eventually washed down into our drains, meaning high levels of triclosan are accumulating in our water systems potentially having a negative impact on the environment.

Triclosan is toxic to algae, which is particularly disruptive to aquatic ecosystems, and there is evidence that triclosan is accumulating at high levels in fish and other aquatic life…

Bear in mind all the material in this email alert is provided for information purposes only. We are not addressing anyone’s personal situation. Please consult with your own physician before acting on any recommendations contained herein.


Zorrilla, L., et al (2009). The effects of Triclosan on Puberty and Thyroid Hormones in Male Wistar Rats. Toxicological Sciences. 107(1) 56-64.

In Vitro Biologic Activities of the Antimicrobials Triclocarban, Its Analogs, and Triclosan in Bioassay Screens: Receptor-Based Bioassay Screens. Ahn et al (2008). Environ Health Perspectives. 116(9): 1203-1210.

Inhibition of the Staphylococcus aureus NADPH-dependent enoyl-acyl carrier protein reductase by triclosan and hexchlorophene. Heath, R., et al (2000). Journal of Biological Chemistry. 275: 654-59.

Antibacterial Cleaning Products and Drug Resistance. Aiello, A.E., et al (2005). Emerging Infectious Diseases. 11(10).

Antibiotic and antiseptic resistance: Impact on public health. Levy, S.B. (2000). Pediatric Infectious Disease. 19(10): S120-2.

Triclosan and antimicrobial resistance in bacteria: An overview. Yazdankhah, S.P., et al (2006). Microbial Drug Resistance-Mechanisms Epidemiology and Disease. 12(2): 83-90.

Bacterial adaptation to biocides: the possible role of `alarmones’, Davies, A.J., Maillard, J.Y. 2001. Journal of Hospital Infection. 49(4).

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