GFSE Review Shows Possible Adulteration

Sandy Almendarez, VP of Content

June 28, 2012

4 Min Read
GFSE Review Shows Possible Adulteration

The American Botanical Council (ABC) recently called attention to the long-standing issue of grapefruit seed extract (GFSE)'s potential adulteration. ABC, along with the American Herbal Pharmacopoeia (AHP) and the National Center for Natural Products Research (NCNPR),  published a review article of 10 peer-reviewed published analytical studies on material labeled grapefruit seed extract. ABC's HerbalGram published the paper as part of the ABC-AHP-NCNPR Botanical Adulterants Program.

The review reported many, but not all, of the GFSE products tested contained non-naturally occurring chemicals, including the microbicides benzalkonium chloride, benzethonium chloride, triclosan and methyl p-hydroxybenzoate.

"We believe there is sufficient evidence in the marketplace from the testing that suggests that some or maybe a great deal are adulterated," said Mark Blumenthal, ABC founder and executive director. "There is a significant amount of apparent adulteration, and this calls for FDA review and testing."

Triclosan, which FDA said hasn't been shown to be harmful to humans, has recently been linked to increased incidence of allergies in children and last year, the New York Times reported studies have shown that triclosan may alter hormone regulation in lab animals or cause antibiotic resistance.

Blumenthal said FDA has not approached the consortium regarding GFSE adulteration, but he said it shouldn't come a surprise to the agency. "I have given dozens of speeches at industry trade conference and scientific conference in the last two years where I have been extremely transparent and forthcoming on what types of adulteration we're looking at."

Blumenthal said GFSE may be a convenient material to adulterate because it lacks a history of use. "We don't see monographs and mentions in ethnobotany of indigenous cultures using GFS for microbial purposes. As far as we can tell, GFSE is a relatively new entry into the dietary supplement and herbal medicine field."

I reached out to 11 supplement companies that market GFSE for comment, but only heard back from NutriBiotic, which said it has performed  random tests throughout the years, and has never had a positive result for the alleged synthetic compounds.

Nutribiotic's website says NutriBiotic Grapefruit Seed Extract CapsulesPlus contain Citricidal®, which it says is synthesized from the seed and pulp of grapefruit. "The process converts grapefruit bioflavonoids (polyphenolics) into an extremely potent compound," the site reports.

A spokesperson for the company said, "Citricidal brand grapefruit seed extract has been sold and marketed by NutriBiotic for over 25 years." The company noted it is not the manufacturer of Citricidal brand grapefruit seed extract and cannot comment on other bands. "Our understanding is that the phenolic compounds (bioflavonoids) from grapefruit are synthesized employing catalytic conversion and ammoniation producing a quaternary compound that has been proven to be nontoxic dating back to 1970 (over 40 years!)."

Blumenthal said, "Claims that a proprietary extraction method would produce those chemicals [found in the review] does not comport to any known chemistry or any known chemical pathway, and we've had that statement supported by a number of Ph.D. chemists. So we don't believe it. We believe these compounds must be added extraneously, not a product of a proprietary extraction process."

Blumenthal encouraged GFSE companies to publish their extraction process in peer-reviewed journals. "Let's see if a peer-reviewed journal would accept it because no one we've talked to say it's possible."

NutriBiotic noted it has not received reports of toxicity from its GFSE products when used according to the company's instructions.

Blumenthal agreed to this point. "We don't have a rash of adverse event reports of products containing GFSE, which might speak to the potential relative safety level of these products," he said.

As the ABC review outlined, many studies have shown non-natural substances in GFSE products. Are these substances created naturally in the formulation process? Are these tests giving false positives? The GFSE marketers aren't talkingat least not to me. Perhaps the next move will come from FDA, which can test samples and review manufacturing processes. But who knows? Maybe FDA has already reviewed them and found they aren't adulterated, but the GFSE companies don't want to divulge their manufacturing processes. At least it appears that GFSE doesn't post an immediate threat as both Blumenthal and NutriBiotic noted a lack of adverse event reports (AERs).

About the Author(s)

Sandy Almendarez

VP of Content, Informa


• Well-known subject matter expert within the health & nutrition industry with more than 15 years’ experience reporting on natural products.

• She cares a lot about how healthy products are made, where their ingredients are sourced and how they affect human health.

• She knows that it’s the people behind the businesses — their motivations, feelings and emotions — drive industry growth, so that’s where she looks for content opportunities.

Sandy Almendarez is VP of Content for SupplySide and an award-winning journalist. She oversees the editorial and content marketing teams for the B2B media brands Natural Products Insider and Food and Beverage Insider, the education programming for the health and nutrition trade shows SupplySide East and SupplySide West, and community engagement across the SupplySide portfolio. She is a seasoned content strategist with a passion for health, good nutrition, sustainability and inclusion. With over 15 years of experience in the health and nutrition industry, Sandy brings a wealth of knowledge to her role as a content-focused business leader. With specialization in topics ranging from product development to content engagement, creative marketing and c-suite decision making, her work is known for its engaging style and its relevance for business leaders in the health and nutrition industry.

In her free time, Sandy loves running, drinking hot tea and watching her two kids grow up. She brews her own “Sandbucha” homemade kombucha; she’s happy to share if you’re ever in Phoenix!


Speaker credentials

Resides in

  • Phoenix, AZ


  • Arizona State University


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