When we see grapefruit seed extract (GSE) listed as an ingredient on a product, 'natural' is one of the first things that comes to mind. However, according to some reports, the use of GSE can be toxic.
Grapefruit seed extract can be found in cosmetics, supplements and pesticides due to the supposed antimicrobial effect attributed to the compounds found in the extract. Recent testing however has shown that natural GSE has no antimicrobial properties on its own. In fact, studies have concluded that the antimicrobial effect of GSE occurs merely from the presence of synthetic preservatives such as benzethonium or benzethonium chloride. One manufacturer claims that their product, Citricidal® is pure, however due to the method of processing, the end result may be contaminated with benzalkonium chloride, triclosan and parabens.
Here’s how grapefruit seed extract is processed:
After all the chemical processing with hydrochloric acid and ammonium chloride, the final composition of the extract is made up of about 60% diphenol hydroxybenzene, a chemical classified as a quaternary ammonium chloride - the same as benzethonium chloride and bezalkonium chloride.
In a 2001 study supervised by chemist G. Takeoka, researchers found these were the primary active ingredients in commercial preparations of grapefruit seed extract. Additional studies confirmed these results. The Environmental Working Group lists these contaminants as a known immune system and respiratory system toxin.
Sources and further reading:
Validation of benzethonium chloride in grapefruit seed extracts
Identification of benzethonium chloride, methyl paraben and triclosan in commercial products labeled as grapefruit seed extract.
Identification of benzethonium chloride in commercial grapefruit seed extracts by chloroform extraction.
Survey of synthetic disinfectants in grapefruit seed extract and its compounded products
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