Grapefruit seed extract (GSE) debunked.

Botanical name: 

Subject: Re: Grapefruit Seed Extract
From: Karen S Vaughan <>
Date: Sun, 9 Jan 2000 22:39:13 -0500

<<I have the little brochure that came with it still sitting here on my desk. It says you can use it orally for dental rinse or throat gargle; ear rinse, nasal rinse, vaginal rinse. External uses: facial cleanser, skin rinse, nail treatment, scalp treatment.>>

I'd be careful about those kinds of uses, at least until more is known about the safety. I prefer it for things like preserving infused oils for external use. See the article below. The problem may not be additives, but pollutants in the raw materials used for the manufacture of the extract. This isn't really a natural extract, just a manufactured product with citrus seeds as a raw material. Even if the research below proves not to be definitive, this should be used cautiously.
"Pharmazie 1999 Jun;54(6):452-6

Aspects of the antimicrobial efficacy of grapefruit seed extract (GSE) and its relation to preservative substances contained.

von Woedtke T, Schluter B, Pflegel P, Lindequist U, Julich WD Institute of Pharmacy, Ernst Moritz Arndt University, Greifswald, Germany.

The antimicrobial efficacy as well as the content of preservative agents of six commercially available grapefruit seed extracts were examined. Five of the six extracts showed a high growth inhibiting activity against the test germs Bacillus subtilis SBUG 14, Micrococcus flavus SBUG 16, Staphylococcus aureus SBUG 11, Serratia marcescens SBUG 9, Escherichia coli SBUG 17, Proteus mirabilis SBUG 47, and Candida maltosa SBUG 700. In all of the antimicrobial active grapefruit seed extracts, the preservative benzethonium chloride was detected by thin layer chromatography. Additionally, three extracts contained the preserving substances triclosan and methyl parabene. In only one of the grapefruit seed extracts tested no preservative agent was found. However, with this extract as well as with several self-made extracts from seed and juiceless pulp of grapefruits (Citrus paradisi) no antimicrobial activity could be detected (standard serial broth dilution assay, agar diffusion test). Thus, it is concluded that the potent as well as nearly universal antimicrobial activity being attributed to grapefruit seed extract is merely due to the synthetic preservative agents contained within. Natural products with antimicrobial activity do not appear to be present."
In addition, there was reportedly a researcher at the University of British Columbia who first discovered the dry cleaning-preservative compounds in grapefruit seed extracts. He was sued by a manufacturer in the U.S. As part of the settlement, he was forced to keep his results quiet and not publish them. I have no details about this, but it makes me cautious about embracing GSE enthusiastically.

Karen Vaughan
Email advice is not a substitute for medical treatment.

Subject: Re: Was Re: Leg Cramps
From: "Janina Sørensen" <>
Date: Wed, 12 Jan 2000 23:08:19 +0100

Hi Kevin, you wrote:
>Theres lotsa good stuff on GSE at the following location:
>(I have no commercial interest in this good stuff.)

There was a good, informative and scientifically sound prove on GSE 's effect two days ago by Karen Vaughan. I had heard for the last two years that serious suppliers were abandoning the extract, because of some doubt as to additives. Her post included a recent publication stating that the extracts which showed activity where themselves preserved with synthetic preservatives which accounted for the reported antioxidant and thereby 'purifying' activity of GSE.

I have stopped considering GSE years ago because of these rumours putting people I trust off this proposed stuff. As most European practitioners have. Her post provided me with the reference. At least here in Europe we now have regulations which are aimed at declaration of all ingredients of a product. So if you read parabens on the ingredient list-- be it methylparaben, ethylparaben or whatever, it includes synthetic preservatives. Your product is not anymore 'natural'.

These parabens- usually coming in a synergy of 3-4, are broad spectrum preservatives, antimicrobials etc. You don't need GSE in that case.

Karen's message was posted just 2 days ago.
Regards Janina