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The Truth About Grapefruit Seed Extract

Since my original post on Grapefruit Seed Extract, I've stumbled upon some new eye-opening information, so I thought I'd expand the subject here.

The big controversy that's been going on for years with Grapefruit Seed Extract lies in its potential to be contaminated with benzalkonium chloride, parabens, and triclosan.  Numerous studies have tested samples of commercially produced GSE and found these contaminants to be present.  (See here, here, here and here.)  The biggest contaminant found is benzalkonium chloride, a chemical that rates a 7 in the cosmetics database that's a known immune system toxin, skin toxin, and possible cancer risk.

Some studies have shown that without these contaminants, a truly natural extract of grapefruit seed and pulp in ethanol or glycerin, had no antibacterial properties.  However, GSE apologists claim that GSE can be effective without these contaminants.  So, what is the truth? Is there such thing as a "pure" GSE, and if so, is it effective?

Grapefruit Seed Extract was first developed in 1972 by a man by the name of Dr. Jacob Harich.  Today, there is one main manufacturer of GSE that defenders claim is pure.  It is sold under the name Citricidal. This website describes how it is made:

  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 glycerine 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.

As you can see, this isn't a truly natural process, it being treated with hydrochloric acid and ammonium chloride.  After all the chemical reactions occur, 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.  In fact, it is nearly chemically identical to benzethonium chloride. This is one possible reason that lab tests have shown GSE to be "contaminated" with benzethonium chloride--the equipment possibly misread the diphenol hydroxybenzene.

Typically, when a truly natural extract is made, plant matter is let to steep in a solvent such as water (as in making tea), in alcohol (like the vanilla extract you'd use in baking), or in glycerin (like with many herbal supplements you'd find at the health food stores) to extract the plant's beneficial or desirable compounds, whether it be a flavor, smell, or antioxidant.  It's a one or two step process that doesn't involve other chemical processing.  GSE is clearly not a natural extract, but a synthetic ingredient, considering it goes through 7 steps of processing and the extract doesn't retain the original compounds present in grapefruit.

Mountain Rose Herbs, one of the most respected and trusted suppliers of organic herbs, extracts, and essential oils lists the composition of the pure GSE they sell (which is most likely Citricidal brand):

Ascorbic Acid- 3%

Glycerol- 36%

Diphenol Hydroxybenzene (Quaternary compound from Grapefruit Bioflavinoid)- 58.5%

Heavy Metals- None detected

Benzethonium Chloride- None Detected

Methyl Hydroxybenzoate - None Detected

Propyl Hydroxybenzoate - None Detected

Triclosan- None Detected

So, while it is pure from other contaminants, it is primarily diphenol hydroxybenzene.  One fallacy I've found on discussion boards online have been that since it comes from Mountain Rose Herbs, it must be safe and organic.  You'll notice that this ingredient is not classified as certified organic on their website. 

When I first posted my Chemical of the Day on GSE, there were some comments written on the post.  I have to now revise my original replies with this new information in mind. 

Sally Leachko founder Meaodwlake Farm wrote:

I applaud your efforts Stepahnie. However, you are only exposing your readers to a fraction of the information available about GSE and controversy that surrounds this ingredient. Is some GSE contaminated? It appears so. Is all? Absolutely not. Meadowlake Farm Honeybee Products uses organic GSE from one source and we've had it tested by an independent lab multiple times. Contrary to what you indicate it has some anti-microbial properties, that is why we use it as a part of our proprietary 100% natural preservation system.

I originally commended her efforts to make sure that her extract was pure.  However, even though her extract isn't contaminated with other chemicals, knowing that "pure" GSE is composed of mainly diphenyl hydroxybenzene, I am forced to rescind my comments.  And while I'm sure that her motives are good (their company seems to work a lot towards sustainability and organic causes), I think that the industry is rife with misinformation, even from suppliers of chemicals to companies. 

Another reader of my original post wrote:

If the ingredient is listed as Extracts of Organic Grapefruit Seed (certified organic by Soil Association Certification Limited) in a product would it be okay?

I originally thought, sure, it's certified organic, it's fine.  However, now I have more information and have to change my reply.

Right now, Citricidal is actually made from organic grapefruit.  But, whether it's organic grapefruit or not, the extract is still going to contain diphenol hydroxybenzene.  But how did this company get a GSE that was certified organic, it being a synthetic chemical?  Well, notice that the certifying body isn't the USDA, by the Soil Association.  The Soil Association is the European organic standard, and the requirements are much less strict than that of the USDA.  They will allow and certify a synthetic chemical like GSE if it meets certain criteria for biodegradability, aquatic toxicity and bioaccumulation.  So, since the grapefruits were organically grown, and it meets the requirements, they approve the extract as organic, even though it's a synthetic chemical.  The Soil Association also approves phenoxyethanol as a preservative ingredient.  The USDA will not certify GSE, or allow it in a certified organic product.  If you see a USDA certified organic product with GSE, it is illegally labelled.  GSE is not on the USDA's list of approved non-organic substances (they allow a few non-organic ingredients like vitamin E in to their products).    

So, let's take a look at diphenol hydroxybenzone.  Why exactly do we want to avoid it?

The makers of GSE states that it's been extensively tested for toxicity and health effects and claim that it is safe.  However, all of these studies only tested the effects when it was taken internally.  When taken internally, chemicals have a chance to be metabolized and broken down by the body.  However, when applied topically, they can be absorbed in the skin and enter the bloodstream in their whole form.

The problem that I see with diphenol hydroxybenzene is the fact that on a molecular level, it's full of benzene rings.  The name "diphenol" means that there are two phenol groups.  Phenol is a benzene ring with one hydrogen and one oxygen molecule.  Chemicals with benzene rings are particularly worrisome in personal care products because once they enter the bloodstream they can mimic the hormone estrogen.  [For a detailed explanation of this, check out my article on Japanese Honeysuckle Extract.]  Estrogen is primarily made up of benzene rings, and our estrogen receptors are made to "fit" benzene rings.  So, when a chemical with a benzene ring enters the body, it has the potential to lock up in the estrogen receptor and can stimulate it. Estrogen mimickers also have the potential to raise levels of estrogen by inhibiting the function of an enzyme called SULT1E1, that helps to remove estrogen from the body. [For more on this, read my article here, scrolling down to "where my discussion begins."]

The strange thing with diphenol hydroxybenzene is that there are no chemical diagrams provided by the manufacturer (or anywhere, even in organic chemistry guides), and the name of the chemical doesn't help (as it should) in finding its chemical structure.  Hydroxybenzene is just another name for phenol, so the name means "2 phenol phenol," which is weird.  My guess is that it's a simplified name for the chemical.  The manufacturer does say that hydroxybenzene is nearly identical to bezenthonium chloride, which looks like this:

The two hexagonal rings you see in the structure are the problematic benzene rings that I was talking about.  And indeed, this chemical has been shown to be an endocrine/reproductive disruptor by a 1995 RTEC study.  It also carries the risk of being a strong skin irritant, and it showed tumor formation at moderate doses.  (see the Cosmetics Database report) However, in its defense, according to National Toxicology Program studies, it exhibited no evidence of carcinogenity or endocrine disruption in a two-year rat and mouse study.  This study did, however, show that the animals treated with benzethonium chloride did have increased inflammation in the body and a slightly lower survival rate than the control group.

The bottom line is that while there is conflicting evidence of the other negative health effects of benzethonium chloride (and the diphenol hydroxybenzene present in GSE), at the very least it's a skin irritant that increases inflammation in the body.  My personal opinion on it is that it is safer than other preservatives. However, if you prescribe to an organic mindset and lifestyle, you will want to avoid Grapefruit Seed Extract, for it is nothing other than a synthetic chemical.

Note: Grapefruit essential oil is natural, and not the same thing as Grapefruit Seed Extract.

References (3)

References allow you to track sources for this article, as well as articles that were written in response to this article.

Reader Comments (76)

You can look forward to my full response soon. I'm compiling a lot of information and can't wait to share it with you. It will take me some time, though, as there is so much information and data to sift through. It will be posted as a separate article on my blog, and it will be a full response to your series about parabens. Good times!

Tue, December 14, 2010 | Unregistered CommenterStephanie Greenwood

Hi...I am reading about this substance GSE because many years ago, in a book on Chinese Medicine for westerners, it was mentioned as a natural anti-biotic. It was very interesting to me because I suffered repeated bouts of tonsilitis, strep throat, etc ever since I was a small child. My parents didn't believe in "ripping" out a kids tonsils, even tho it was, at the time, the thing to do. Consequently, I took alot of anti-biotics as a kid and into my 20's. When I was about 26 I read about GSE, and I subsequently came down with a terrific bout of strep throat - white spots and all. I HATE going to the doctor, and I'm a bit of an adventurer, so I went to my local health food store and bought a little plastic bottle of GSE. At the time (this was in the early 90's) there was NO information about dosing yourself with this stuff internally - the bottle contained no such instructions and in fact said it was NOT to be taken internally. Well, I did. I put about 8-10 drops (tiny drops of the oil) into a shot glass and filled the shot glass with orange juice. I slugged that down (tastes HORRIBLE) about every 8 hours for a few days. All I know is, it cured my strep throat. I've never used it since - but it did work. No question about it. I don't use it for all and sundry - I only tried it as a sort of experiment. It did upset my instestines, slightly, but even that I thought might have had a potentially beneficial "cleansing" effect and I get the exact same reaction from various pharmacy dispensed anti-biotics. So...for what it's worth. I believe that ALL things should be used in moderation. There is NO magic substance on the planet, mores the pity. Anyway...Happy New Year to all.

Wed, January 5, 2011 | Unregistered CommenterChristine O'Shaunnessy

Thank you SO much for your care and thoroughness.

I just read a recipe for a homemade "all natural" mouthwash containing GSE. It sounded really good from the description. Now I know to leave out the GSE.

I'm SO grateful to have the facts!

Thu, September 29, 2011 | Unregistered Commentermina

Thank you so much. Very clear headed. I like the debate between you scientific jousters, but getting over my head for sure. As long as you can keep away from being personal or point scoring the debate is important to give different sides to the issue. Baseline seems to be; okay it is manufactured (artificial) not totally of natural origin. But is it useful? Or is it terribly harmful? Used carefully is it helpful for various things? If you want to treat that stubborn thing called systemic candiasis, is this the product to do it or not? Even if it is eostrogenic, surely you will feel a lot better once you get rid of the toxins in your body from candida....then stop taking the Citracidal and start on the probiotics. ???? And the reason I am looking at it, hopefully just a trivial thing, but will it treat warts?! And will it do it better than a mixture of asprin and vinegar....oh, um, but asprin is artificial even though it comes from Willow, and was developed by the Nazi's? Hippies; don't drive Volkswagens any more!

Thu, November 24, 2011 | Unregistered CommenterDUMB WAITER

Systemic candida can be HARD to kick. I do recommend avoiding GSE, as there are much more powerful substances that can knock out this stubborn yeast. Probiotics (pills and fermented foods) are an important part of an anti-candida program. But also a strict dietary regimen and other supplements and functional foods. There is way too much involved to get in to here--you will need to find a certified Naturopath or other specialist that can tailor a treatment program just for you. They can also give you the best advice for wart treatments.

Tue, December 6, 2011 | Registered Commenter[Stephanie Greenwood]

So the white bottle, ol' reliable Original GSE is actually chock full'o chemicals. Sh!t. I guess I better stop recommending it to people. If I am reading you right, there is very little GSE on the market that does not have these chemicals, and the stuff that does not is probably not effective. What a bummer. I have used this stuff for years, never suspecting it was anything but a natural extract like orange oil or anything else. I have been recommending it to members of my online community to use in the soak water for sprouting, to kill off any possible contaminants in the seeds.

Its funny how little we question labeling. If it says organic, we think it must just be something they made by running grapefruit seeds through an oil press. It sure tastes the same as when I crunch down on a grapefruit seed. Is there any brands that don't have all this crazy stuff in them? I thought the original GSE was totally safe.


Fri, February 3, 2012 | Unregistered CommenterDaniel

I'm so glad I read this article & looked deeper into this GSE before giving it to my 6mo to treat thrush. I was reading about using a natural approach to her condition and I read a drs. suggestion of using 10 drops of GSE to a one ounce cup of distilled water to get rid of her thrush (yeast infection of the mouth). Thank goodness I didn't

Thu, March 22, 2012 | Unregistered Commenterkoreen

I really appreciate this effort to bring the dangers of GSE to light. I believe people are continually fooled by the natural-sounding name of this ingredient. It's amazing the power a name can I have. I am not against all synthetics by any means, but it does seem strange to me that people who are natural ingredient purists will continue to defend this ingredient which, even in the best case scenario of it not being contaminated with dangerous preservatives, is still a synthetic that has not undergone rigorous testing.

Because I share your concern about all the misinformation surrounding cosmetic ingredients, I am also concerned with some misinformation you pass on here. The Skin Deep database ratings are meaningless, as it is full of complete misreadings of scientific data. It is an excellent idea, but unfortunately executed poorly, with data interpreted by people who simply lack the knowledge to interpret it.

Also, it's simply not true that ingredients applied to the skin will be more toxic than ingested. Even though you have a lot of other good points here, it's hard for me to trust certain conclusions if you repeat myths such as all skincare ingredients being absorbed whole into the bloodstream. The issue with GSE makers claiming it is safe is more with the quality of their research, and the fact that long-term data does not exist.

Mon, June 4, 2012 | Unregistered CommenterRose

i would suggest a good daily dose of a quality pro-biotic to restore intestinal bacteria flora!

Tue, March 19, 2013 | Unregistered Commenterjudi bola online

I too was considering using GSE to treat my gut problem (possibly SIBO), because of: . The post at that link recommends against using probiotics for it. Although that page may be problematic (re: replies to it), there are several anecdotal reports in line with the recommendation to avoid probiotics (re: replies); plus my doctor said not to take them. Because of Stephanie's post here and I won't try GSE either.

Thu, April 11, 2013 | Unregistered CommenterDaniel L

I'm also concerned about such a caustic substance stored in plastic. But GSE cured a gum infection that I had that was causing my gums to recede. It was incredbily effective, but I rinsed three time a day with the recommended dilution.

Sun, April 21, 2013 | Unregistered CommenterBev Jo

Stephanie - Did you ever post your response to the arguments presented by Dene Godfrey? At the point the conversation was left off, I believe Dene had the stronger argument.

You also claimed there are more powerful substances to get rid of candida. That may be true but the toxicity of things like Nystatin, Ketoconazole, Clotrimazole, Fluconazole, or Itraconzazole are FAR more suspect that GSE, in my opinion.

Fri, September 20, 2013 | Unregistered CommenterWeston G

Yes, Weston, you can read my full response to Dene's argument here:

Mon, September 23, 2013 | Registered Commenter[Stephanie Greenwood]

I was disappointed to read about the potential toxicity of GSE. I'd previously taken 12 drops in a pint of water and actually felt markedly better, lighter, somehow clearer-headed. Perhaps this was my imagination, though my rather blunt sensibilities in most other aspects would suggest otherwise. I'm tempted to experiment further despite the potential effects... I remember reading an article about the little know gut flora that saps ones energy whilst literally poking holes though the intestines... all very probably rubbish science concocted in order to sell something. Who knows what to believe anymore!

Thanks Stephanie for your chemists-eye view. Always a pleasure.

Sat, October 26, 2013 | Unregistered CommenterSimon

anyone who has used gse knows how useful it is for self-treatment, and fir achieving considerable freedom from the conventional medical industry. I have switched to organic gse from germany (GSE Vertrieb, in Saarbr├╝cken, only prob is they are wholesale and their distributor 'Naturmueller' doesn't cover Australia. had it sent to a friend in Germany who sent it on to me. Worked brilliantly. German postage weirdly cheap. Nice!)

The difference in taste is phenomenal. Citricidal makes one gag, let's face it. The organic stuff has by comparison hardly any taste/bitterness. Beautiful. Apart from using it to avoid all the random other-people's-colds I didn't want, I also used it together with lysine and olive leaf extract to ward off a second attack of shingles (face/eye. not cool.), thus avoiding a second course of conventional "antivirals" which do work short-term but cause relapses in the long run unless you want to keep taking them and try your best to taper off... No thanks. ahoy, Jeannie

Fri, November 15, 2013 | Unregistered CommenterJeannie

Hello Stephanie,

I was doing some homework on how to disfinfect laundry with bleach alternatives and GSE was touted as a great substitute, with it fast becoming the choice for hospitals.

What do you think? I want to sanitize my laundry (towels, underwear) but don't want to use bleach. But after seeing so much controversy about GSE, I am reluctant to try this too, although I don't plan on ingesting it orally, just for laundry.

Can you suggest some other alternatives? I also don't want to use vinegar, borax, line drying (not practical), ect. I have bought some tea tree oil but I imagine it cannot kill some pathogens that GSEs can (yeast spores) should I ever need to.

Thank you in advance,


Tue, November 26, 2013 | Unregistered CommenterSophie

Just wondering how effective GSE is in the treatment against bacteria and fungi on plants? Any negatives about using it on plants?

Thu, January 9, 2014 | Unregistered CommenterFreddie Viljoen

It's seems like I could dry out my own organic grapefruit skin/seeds and grind into a powder and create a tincture using glycerin. Any guess on if this would be anti-fungal?

Sun, February 9, 2014 | Unregistered Commenteritsme

@Itsme--Unfortunately there's no way to know without testing it. I doubt that it would be--otherwise they wouldn't have to put it through so much chemical processing to create the "extract."

Mon, March 3, 2014 | Registered Commenter[Stephanie Greenwood]

Thanks so much for this article. I have been a firm convert to Grapefruit seed extract in a topical form and am a bit confused with the technical jargon you have written. Can you sum up with a conclusion?

Sat, March 29, 2014 | Unregistered CommenterGaye Simms

Hello Stephanie,

I am so glad to discover the web page as I was researching on safety of GSE. The post was published in 2010. Where there any other new research on the grapefruit seed extract? What is your final verdict?

Thank you for all your work! I know I will frequent the web page.

Mon, May 26, 2014 | Unregistered CommenterRina

@Rina--nope--no new developments with GSE. Still a highly processed chemical consisting of mostly quaternary ammonium compounds.

Thu, May 29, 2014 | Registered Commenter[Stephanie Greenwood]

Found GSE when I was researching Morgellons. I could tell right away when they came out with the bottle without the label. It did not work as an antifungal. They removed the citricidal from it. People were buying up every bottle everywhere that still had the label. I put it in my laundry, hot tub, dish soap, on my skinm my bird's water, my water. I used to use skin lotion and other products that used it as a preservative. I called all manufacturer's when I found out they changed their products. They all said the FDA and CDC banned citricidal.
Watch out folks, when something is inexpensive , and works, like herbs, they will try to take it away from us. You can still order Maximum GSE online with the citricidal. Guess what it's twice the price of the old bottle. I stocked up though.

Sat, May 31, 2014 | Unregistered CommenterPam

I was recently at a health institute in southern Florida and eating sprouts as a major part of each meal was a very significant part of their program. The only disinfecting ingredient they recommended for growing sprouts was GSE. I've started growing sprouts and need to clean jars, trays and other items before each new batch. Is there something better (safer) to use or can you refer me to a reliable site for more info.

Wed, July 2, 2014 | Unregistered CommenterJohn Lynch


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.

Thu, July 17, 2014 | Unregistered CommenterPAUL

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