Author: marco zante
Date: 29/12/2010



Triclosan is a molecule used since 1972 for its antibacterial properties found in many detergents, soaps, cosmetics, pesticides and toothpaste. Its chemical structure is similar to dioxin and other toxic compounds, which led to address studies on its potential toxicity.


The IUPAC name is 5-chloro-2-(2,4-dichlorophenoxy)phenol and it is a chlorinated derivatives of phenol.
Triclosan is classified as a broad-spectrum antimicrobial agent because it is effective against a wide range of microbes; the term antimicrobial implies that the chemical is antibacterial, antifungal, and antiviral. Because Triclosan is extremely powerful, very low concentrations can effectively kill bacteria.


The molecule has a positive effect in toothpastes, even compared to other uses of the same.
Toothpastes, containing triclosan, are effective in improving plaque control, gingivitis and periodontal health. Other toothpaste formulations are effective in reducing the formation of calculus, extrinsic tooth stain, dentine sensitivity and oral malodour.

Dentifrices--an update. Davies R, Scully C, Preston AJ. 2010 Nov
Common therapeutic approaches for the control of oral biofilms: microbiological safety and efficacy. Gilbert P, McBain A, Sreenivasan P. 2007 Oct

The use of Triclosan in toothpaste is due to to the following characteristics:

But it's also used in other ways:

  • As a preservative, placed in cosmetics and deodorants.
  • As a pesticide, added by the EPA as a useful tool for agriculture.


Triclosan appears to be readily absorbed from the gastrointestinal tract and has a rapid turnover in humans. The high lipid solubility of the substance gives rise to questions regarding distribution properties and accumulation.


Triclosan effectively eliminates gram+ bacteria, gram-, mycobacteria, fungi and spores; introduced 40 years ago to make preoperative surgical scrub. It needs a copolymer of maleic acid + zinc citrate and fluoride to achieve maximum effectiveness.
By stealing active sites from the natural substrate, Triclosan systematically kills bacteria by stopping fatty acid chain growth. This, in turn, stops the growth of the cell membrane and effectively kills the cell.
Fatty acid synthesis in bacteria is a multi-reaction process with different enzymes catalyzing each chemical reaction. One gene encodes one enzyme; Triclosan interferes with the gene that regulates the entire process. For example, in E. coli and M. tuberculosis bacteria, the regulatory gene, named FabI, encodes the enzyme called enoyl-acyl carrier protein reductase (ENR). Triclosan acts as a competitive inhibitor when it binds to the active site of the ENR enzyme and forms a FabI-NAD+-triclosan complex. Triclosan steals the active site on the ENR enzyme to form a complex never intended by the regulatory gene. The complex is analogous to a defected product in a factory. The formation of this complex signals Triclosan's success. The alternate complex is unable to continue in the process of fatty acid synthesis, effectively ending the elongation of the fatty acid.
Construction and maintenance of the cell membrane relies on synthesis of fatty acids. Triclosan impedes fatty acid synthesis in bacteria and therefore weakens the cell membrane and effectively stops bacteria from functioning properly.



The only side effects reported in humans after exposure to triclosan are cases of contact dermatitis or skin irritation.


According to some sources, the compound can accumulate in the tissues of living organisms and in breast milk, its accumulation can cause abnormal liver function, lung function, cause infertility, impaired immunity and high-dose paralysis.
And allow the use in cosmetics at a concentration of about 0.3%.
The Scientific Committee on Cosmetic Products of the European Commission in 2002 concluded that the use of Triclosan in the conditions currently in force is safe.
In Sweden, however, the Ministry of Health not be used after a study by the University of Stockholm.


Triclosan is an antibacterial broad, and like all other antibiotics for his wide-ranging use of excessive and wrong, could lead to bacterial resistance to it but also to other drugs.


AddThis Social Bookmark Button