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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 (77)

Note: Grape Seed Oil also not the same thing. It is cold-pressed from the seeds of grapes, and is completely unrelated to GSE.

Thu, February 11, 2010 | Registered Commenter[Stephanie Greenwood]

Thank you for keeping us safe and informed! This is great information.

Thu, February 11, 2010 | Unregistered CommenterMelissa

Thank you for taking some time to delve into the cult of GSE, and for being willing to go into some of the chemistry behind what is going on with this material.

Mon, February 15, 2010 | Unregistered Commentersara

So, I am confused. Are you saying to avoid GSE in external products, but it is ok when taken internally?

Mon, February 15, 2010 | Unregistered Commenterglh

I wouldn't say that yet. For this particular article I've focused on its effects when applied externally, and have not studied its internal benefits or effects to recommend either way. The main point of my article is that GSE is a synthetic chemical, not an organic extract. If you're avoiding synthetics (parabens, pesticides, BPA plastics, etc) as much as you can, avoiding GSE would be part of that lifestyle choice.

Mon, February 15, 2010 | Registered Commenter[Stephanie Greenwood]

Is the GSE dispensed from a plastic bottle? Is this another plastics issue, having zip to do with GSE?

Tue, February 16, 2010 | Unregistered CommenterElaine Dolan

No, I wouldn't classify this as a plastics issue. It's the chemical structure of the GSE itself.

Tue, February 16, 2010 | Registered Commenter[Stephanie Greenwood]

Thanks, Stephanie. I had been thinking that GSE was indeed an organic extract of sorts. I guess I will curtail my use of it until more info comes out.

Wed, February 17, 2010 | Unregistered CommenterGlh

Thank you so much for this information! I have been trying to get to the bottom of GSE for weeks now. There's not a whole lot of information out there.

Fri, February 19, 2010 | Unregistered CommenterVictoria

Thank you for taking the time and effort to research this ingredient. I would say, however, that I found it interesting that you waited until the very last part of your article to say that this is a good "synthetic" preservative. I'm not sure about your chemistry and I'm really not sure how you are so sure about the absorption of said chemical through the skin. There is a lot of debate out there concerning skin absorption rates vs internal metabolism. I think that's a stretch, but am forwarding this on to medical professionals for a better look. Finally, If one is to formulate any product with water content, a preservative is absolutely vital, safe and fairly irresponsible without it. GSE seems to be a better choice but we keep finding articles such as this that obviously are biased toward their own products. I don't believe from looking at your website that you use water in any of your products? It's impossible to make a cream or lotion without a water phase - period, end of discussion. That water has to be preserved. If your article was simply to question the "natural" label for GSE, I would say good job, probably well done. But you spent most of your article portraying a very effective, at least naturally derived preservative as one of the BAD guys. I hardly would put it in the same category as parabens.

Tue, March 9, 2010 | Unregistered CommenterAnn Wooledge

The aims of my article are to:
1. Clear up the controversy surrounding the ingredient (is it an effective preservative on its own or only due to chemical contaminants).

2. Expose what GSE really is, so that people following a holistic, completely organic lifestyle can make an informed choice.

While the effects and absorption rates of these ingredients are being studied and debated, until the complete safety is proven, many people chose to err on the side of caution. It is my aim to inform people so they can make their own choices. GSE is not unlike parabens. It contains multiple benzene rings and is a synthetic preservative.

I do refuse to make water-based products. More information can be found here:

Tue, March 9, 2010 | Registered Commenter[Stephanie Greenwood]

Thank you for this thorough discussion. I know a handful of people who promote GSE as a "natural" (and therefore safe) alternative to "chemicals". It simply doesn't mafe sense that such a broad spectrum anti-microbial would exist in nature. Even our own bodies are made up of more cells from bacteria, viruses, fungi, etc than it is of human cells. We depend on a balance of the various bacteria, fungi, etc for health. GSE is going to kill healthy "good" bacteria as well as "bad" bacteria. I object to the junk science techniques used by proponents of GSE. They take advantge of people's ignorance and mistrust of science and use it to manipulate those very people.

Mon, March 15, 2010 | Unregistered CommenterL Parker, MPH

I'm thrilled to find your website!

Here is an article I posted about GSE years ago. I'm credited as "the former Founder of the Natural Ingredient Resource Center." I am and always will be the Founder of the Natural Ingredient Resource Center. I am the former owner, however.

Tue, March 30, 2010 | Unregistered CommenterSusan Sawhill Apito

Fancinating, and disturbing all in one.
I have been curing everything with this stuff for years now, and recommending it to everyone. Who knew???
So I'm now wondering if this still good to wash my produce, clean my cutting boards, and clean my juice machine parts in?
Thanks for sharing your findings!

Tue, May 4, 2010 | Unregistered CommenterJennifer S.

Ha ha! I've found tons of products that don't use water as a base. It is extremely possible! Water is just a filler. Also, I had no idea that water had to "be preserved." Water can also be drying to the skin- oils are a much better option. Stephanie- keep up the good work!

Wed, July 28, 2010 | Unregistered CommenterLaura Bradford

@Jennifer--sorry I missed you comment here. I would just use hot water and soap to clean your kitchen equipment and such.

@Laura--Thanks! Also make sure the products don't contain aloe vera juice or hydrosols, as these too are 99.9% water and need to be preserved.

Wed, July 28, 2010 | Registered Commenter[Stephanie Greenwood]

Well, I saw many people like GSE. I was thinking of using it to help kill off bad bugs in my guts. Now I don't know. Do you have a good suggestion for an alternative that's natural if we don't use GSE?

Thu, September 2, 2010 | Unregistered CommenterYaxi

i would suggest a good daily dose of a quality probiotics to restore intestinal bacteria flora!

Sun, September 5, 2010 | Registered Commenter[Stephanie Greenwood]

Sorry, but whilst you actually talk a lot of sense about the GSE situation, you are totally misinformed about the benzene ring! Compounds with a benzene ring do NOT automatically mimic oestrogen. Benzene rings are so common in natural chemicals they are in thousands of different compounds in our own bodies, and everywhere else throughout the natural world. The benzene ring is one of the fundamental building blocks of many/most natural substances. Even just neat benzene alone does not mimic oestrogen! I do not understand where you get this information from!

Fri, December 10, 2010 | Unregistered CommenterDene Godfrey

Hi Dene! Good to see you here!

Of course, not everything with a benzene ring is estrogenic. Numerous beneficial antioxidants and compounds contain benzene rings. Many of the building blocks of life are built of benzene rings.

Estradiol is one of those building blocks. The most active end of the estradiol molecule is the end with the benzene ring. Our estrogen receptors are built to fit this benzene ring, so when molecules with a single benzene ring on an end enters our bodies, it has the possibility to enter these estrogen receptors and thus stimulate the receptor molecule (thus acting estrogenically.)

There is much evidence that benzene acts estrogenically.

This study found that women exposed to benzene developed irregular menstrual cycles:

As did this study:

And this study found increased risk of breast cancer when exposed to benzene:

It is well-known that polyaromatic hydrocarbons (benzene-based compounds) act estrogenically. Look at all of the known estrogen mimickers...parabens, phthalates, bisphenol A...they all have benzene rings at the end of the molecular structure. All estrogen mimickers have benzene rings or something very similar in shape.

If there were no evidence that GSE acted estrogenically, I wouldn't indicate it as such entirely based on the molecular structure. But there IS evidence of its estrogenic nature, and my point of bringing up the benzene rings is because it is that particular end of the molecule that is likely to be the culprit.

Fri, December 10, 2010 | Unregistered Commenter[Stephanie Greenwood]

Hi Stephanie - thanks for the lovely welcome! I wish I could agree with you, but I can't! The first two references you quote are not connected with oestrogenicity; only to the disruption of the menstrual cycle, and there is not neccesarily any connection. The 3rd reference was highly equivocal in its claims, saying that it only moderately supported the claims - very different to full proof. The real part of the molecule that determines oestrogenicity is NOT the benzene ring, but the substituents attached to the ring. One example of this is the fact that 4-hydroxybenzoic acid (the major breadown product of all parabens) has NO measurable oestogenic activity, whereas butyl 4-hydroxybenzoate (butylparaben) has weak oestrogenic activity (100,000 times weaker than oestradiol), and this leads me on to another important point, Oestrogenic activity is NOT the same as being an oestrogen mimic, despite the slightly similar naming used. There is no real evidence that any parabens actually mimic oestrogen and, indeed, the stronger evidence suggests that parabens have significant differences in the effects on global gene expression (the indicator of oestrogen mimicry) compared with oestradiol. Oestrogenic activity is simply a measure of the affinity of a substances for oestrogen binding sites - it is the effect on global gene expression that is the real issue, and parabens are in the clear here!

Just for the record, concerning parabens, here are some links to articles that you may find of interest:

Sun, December 12, 2010 | Unregistered CommenterDene Godfrey

Dene--you mght find this study interesting click here

"It can be concluded that removal of the ester group from parabens does not abrogate its oestrogenic activity and that p-hydroxybenzoic acid can give oestrogenic responses in human breast cancer cells."

I have more to add, but am processing orders at the moment. I'll have a full response in a couple of days for you.

Mon, December 13, 2010 | Unregistered CommenterStephanie Greenwood

I appreciate that you have found this "evidence", Stephanie, but it is important to avoid relying on a single study (especially one by Darbre whose track record with parabens studies is far from exemplary). There is one other study I have seen that also ascribes oestrogenic activity to p-hydroxybenzoic acid, but there are more studies that find none and, hence, the weight of evidence is in favour of p-HBA not having oestrogenic activity, further supported by the several studies that have shown a marked reduction in the oestrogenic activity as the carbon chain length gets shorter on the ester group. Every single study by Darbre since 2004 relies on her having "detected" parabens in human breast cancer cells. Her work was deeply flawed and highly inconclusive, but she has staked her reputation on parabens being an issue. Until there is actual proof that parabens cause problems, the jury remains firmly out on this, no matter what studies Darbre contrives to put together to support her hypothesis. Sorry if this sounds rather dogmatic, but if you check out those links I provided earlier, hopefully you will understand my scepticism.

Mon, December 13, 2010 | Unregistered CommenterDene Godfrey

So it is your opinion that all studies with Darbre's name should be thrown out?

Mon, December 13, 2010 | Unregistered CommenterStephanie Greenwood

lol - in my wildest dreams! But seriously . . . not at all - just treated with great caution. Her 2004 study on parabens in breast tumours would certainly be a genuine candidate for permanent removal from the scientific literature - and I don't make that statement lightly - it really was that bad in so many different respects. The remainder just need to be seen in context. Some of the concentrations she uses are much higher than she "detected" in the 2004 study, and some of the studies are carried out on cells that are specifically designed to be cancerous and are mostly of academic interest rather than having any real practical value. Although it was not a published study, the work by Darbre to which I referred in Part V of the parabens series I gave you links to was anoher example of extremely poor science from this researcher.

Mon, December 13, 2010 | Unregistered CommenterDene Godfrey

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