January 15, 2019 2 min read

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:

  1. Grapefruit pulp and seed is dried and ground into a fine powder.
  2. The powder is dissolved in purified water and distilled to remove the fiber and pectin.
  3. The distilled slurry is spray dried at low temperatures forming a concentrated flavonoid powder.
  4. This concentrated powder is dissolved in vegetable glycerin and heated.
  5. Food grade ammonium chloride and ascorbic acid are added, and this mixture is heated under pressure. The amount      of ammonium chloride remaining in finished Citricidal is 15-19%; the amount of ascorbic acid remaining is 2.5-3.0%.
  6. The ammoniated mixture undergoes catalytic conversion using natural catalysts, including hydrochloric acid and   natural enzymes. There is no residue of hydrochloric acid after the reaction.
  7. The slurry is cooled, filtered, and treated with ultraviolet light.

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​


Leave a comment

Comments will be approved before showing up.