Many ‘Grapefruit Seed Extracts’ adulterated with synthetic disinfectants, says nonprofit research consortium

By Stephen Daniells

- Last updated on GMT

Related tags Fda

"There does not appear to be any historical or traditional medicinal use of grapefruit seed" - Mark Blumenthal, ABC
"There does not appear to be any historical or traditional medicinal use of grapefruit seed" - Mark Blumenthal, ABC
The majority of products containing 'grapefruit seed extracts' may be adulterated with synthetic additives, according to a new review from a nonprofit research consortium.

The review is published in the American Botanical Council’s journal HerbalGram,​ and is part of an ongoing series produced by the American Botanical Council-American Herbal Pharmacopoeia-National Center for Natural Products Research (ABC-AHP-NCNPR) Botanical Adulterants Program.

Regulatory action

Mark Blumenthal, ABC’s Founder and Executive Director, called on the US Food and Drug Administration to immediately investigate the apparent adulteration of grapefruit seed extract-containing products and take appropriate regulatory action where necessary.

“This includes testing commercial grapefruit seed extract-containing products, inspecting manufacturing facilities, reviewing production records, and whatever other actions are appropriate to determine if adulterated, illegal products are being sold. If such a determination is made, the FDA should immediately take appropriate enforcement action,”​ he said.

Warning Letters have previously been issued by FDA to several companies for illegal drug claims describing antimicrobial and antifungal effects of grapefruit seed extract-containing products sold as dietary supplements and cosmetics, among other violations for those products cited by the agency, said ABC. However, FDA did not deal with the issue of adulteration.

NutraIngredients-USA contacted the FDA for comment, but no comment was received prior to publication. 

A leading manufacturer of grapefruit seed extract supplements was also contacted, but no comment was received prior to publication.

History of use?

‘Grapefruit seed extract’ has been on the natural products market for over 30 years as an ingredient in or preservative for cosmetics and related preparations for external use, and also in dietary supplements.

The ingredient is touted in modern, popular literature as a natural antimicrobial agent for both topical and internal use, including, but not limited to, eczema, acne, cold sores, athlete’s foot, sore throats, thrush, vaginal infections, colds, various gastrointestinal disorders and infections, allergies, and gingivitis.

However, according to the new review, many grapefruit seed extracts contain non-naturally occurring chemicals, including the microbicides benzalkonium chloride, benzethonium chloride, triclosan, and methyl p-hydroxybenzoate.

The article was authored by John Cardellina II, PhD, a natural product, organic, medicinal, and analytical chemist. Dr Cardellina reviewed 10 published analytical studies of commercial ingredients and/or products labeled as ‘grapefruit seed extract’ since 1991. No new chemical testing was performed by the Botanical Adulterants Program.

Dr Cardellina’s review revealed that the synthetic microbicides present in the grapefruit seed extracts have changed, making a stronger case for the probability of adulteration.

“The fact that the antimicrobial components found in grapefruit seed extracts changed from 1991 to 2008 not only argues against such in situ synthesis (i.e., occurring naturally or synthesized in the processing of grapefruit seed material itself), but is suggestive of efforts by manufacturers of these commercial materials to stay one step ahead of analytical methods to detect adulteration,”​ he wrote.


A 2001 article in the Journal of Agricultural and Food Chemistry​ (Vol. 49, pp. 3316-3320) states that a manufacturer of grapefruit seed extract-containing products had previously claimed that the determination of benzethonium chloride in such products was an error and that this was “due to the similarity in molecular weight of the quaternary ammonium compound (said to be formed in the proprietary manufacturing process) with that of benzethonium chloride”​.

The 2001 article – authored by scientists from the Agricultural Research Service at the U.S. Department of Agriculture – tested such a claim and confirmed the presence of benzethonium chloride in various samples.

“It seems unlikely that benzethonium chloride is formed during any extraction and/or processing of grapefruit seeds and pulp,”​ concluded the ARS scientists.


Commenting on Dr Cardellina’s review, ABC’s Blumenthal added: “This situation is especially curious and troubling given the fact that there does not appear to be any historical or traditional medicinal use of grapefruit seed, or preparations made from it in any treatises or monographs in traditional literature, pharmacopeial compendia, etc​.

 “We do not know whether all products claiming to contain ‘grapefruit seed extract’ are adulterated,”​ he added. “But, as our article shows, there is ample evidence in the scientific literature to raise serious concerns about the probable adulteration of such products.”

Source: HerbalGram
2012, 94:62-66
“The Adulteration of Commercial ‘Grapefruit Seed Extract’ with Synthetic Antimicrobial and Disinfectant Compounds”
Author: J.H. Cardellina 

Related topics Suppliers GMPs, QA & QC Polyphenols

Related news

Show more

Related products

Related suppliers

Follow us


View more