Saturday, October 16, 2010

Preservatives: Grapefruit seed extract (GSE) is NOT a preservative

Grapefruit seed extract (GSE) is derived from the seed and pulp of grapefruits, and it may contain many lovely things - anti-oxidants, flavonoids, Vitamin C, citric acid, phytosterols, and tocopherols - but it is NOT a preservative. It may behave as an anti-oxidant in our products, but it will not keep the beasties out of your lotions and other creations.

Study after study has shown that the preserving power of GSE comes from the preservatives added to the product. Various studies have shown GSE contains benzethonium chloride, benzalkonium chloride, triclosan, and various parabens, and these are what offer the bacteria, fungus, yeast, and mould fighting powers attributed to GSE.

Here are a few studies that might interest you. I could post more, but I think these really do make the point pretty well.
Identification of benzethonium chloride in grapefruit seed extracts.
More information on benzethonium chloride in GSE. 
Aspects of the antimicrobial efficacy of GSE and its relation to preservative substances contained. 


p said...

Yay for your research, Susan!!

I still feel a bit confused by the issue.... I came across an independent study showing that Citricidal brand GSE is in fact effective against a variety of bacteria:
I'm guessing you ran across this study in your online research, too? Anyway, Citricidal manufacturers claim that their product is free of the synthetic preservative responsible for the antimicrobial activity of a lot of GSEs, benzethonium chloride. I wonder if they're, um, lying? Otherwise, I don't know what to make of this, if it's conflicting evidence to what you've presented?

Madeaj said...

Hi P

I was looking GSE too, but all the data I can found says it is a broad-spectrum antimicrobal, not a preservative. That information came from the Citricidal website.

I looked at some of the products containing Citricidal from a link on the website. In addition to Citricidal, some of the products contain a variety of parabens, common preservatives.

Here are some links

One of the shower gels with GSE and parabens for preservatives

Susan Barclay-Nichols said...

Hi p. The link you sent me does not indicate if the Citricidal contains any preservatives, but I found this...

Their own site states: "It contains 60% active ingredients (quaternary compound from grapefruit bioflavonoids) and 40% Vegetable Glycerin USP." Quats are preservatives, but are they really found in GSE naturally?

A further search (from this page at Live Strong) notes the following...

The exact nature of the preservative ingredients in Citricidal is in question. Nutriteam states that the preservative qualities come from quaternary ammonium compounds that are safely chemically converted from the natural polyphenols found in the GSE. A U.S. Department of Agriculture report from 2001 states the toxic substance benzethonium chloride is found in the product as an antimicrobial. But an NCBI report states that an unknown solid similar to benzethonium chloride is the preservative. Since the parent company states the process of extraction is proprietary, it is impossible to verify the exact nature of the preservatives.

I think it's safe to say there are quaternary compounds that behave as preservatives in Citricidal, but are they naturally occurring or are they added? So far the answer seems to be they are added to the Citricidal product.

Great research, p!

Randi Carr said...

Thank you for this post, Susan! Thank you, Thank you, Thank you!

solquartocrescente said...

Grapefruit seed extract can be bought organically for example from Soap Kitchen, and it works, but its not a very good preservative (sodium benzoate works better).

If you use 0.5% spoilage will occur most of the time. At 1-1.5% it protects products somewhat, but still bacteria and molds grow after a couple of weeks. Not effective! Only delays their growth a bit.

I am going to try to use it at 3% to see if it protects better, and combined with essential oils and tinctures. Creams with 3% GSE still don't cause me any allergy at all.

Might be good for preserving thick liquid soaps, but on creams I definitively don´t recommend it on its own!

Forget the hype. Maybe some brands use it, because they apply extreme clean conditions when making their creams (like a sterile environment).

Susan Barclay-Nichols said...

solquartocrescente said...
Grapefruit seed extract can be bought organically for example from Soap Kitchen, and it works, but it's not a very good preservative (sodium benzoate works better).

GSE is never a preservative, except when the product is preserved thanks to the preservative in the GSE. You can use it at 10% and it's still not an adequate preservative, and any products that use it as a preservative should be considered unpreserved. Sodium benzoate isn't a broad spectrum preservative - it's bacteriostatic and can help with fungus - so you need to couple it with something else.

solquartocrescente said...

Hi Susan,

Grapefruit seed extract, made only with glycerin, no additives added, IS a preservative but a weak.

You can do it yourself, or buy certified organic GSE from certain suppliers like Soap Kitchen. This way, there are no additives. And it still works, no matter what studies have said.

At 3% it protects against bacteria but not every mold. If you dont believe me, try it yourself. The cream remains clean of bacteria and mold. I have done lab tests. It remains clean for at least 2 months.

However, it does not pass challenge tests (if you insert a dirty finger with mold spores, it will spoil). But if you have a lotion, where you cannot insert fingers, then the product is in fact preserved.

Since I was curious to have this controversy solved, I did the tests myself and this is what I found.

Susan Barclay-Nichols said...

Hi solquartocrescente! Grapefruit seed extract isn't a preservative. There are countless studies on this topic, and it has been shown that the only preserving power GSE might have, comes from any preservatives added to it. It might be considered an anti-oxidant, but it is not a preservative.

I really appreciate that you've shared your experiences with GSE, but this doesn't mean you can claim GSE is a preservative. It might have worked for you, but this is not scientific evidence - this is your experience. The controversy is not resolved...GSE is NOT a preservative, regardless of your experiences.

Please send any good studies done by reputable groups showing GSE is a preservative to me! Remember - extraordinary claims require extraordinary evidence. When you go against the conventional wisdom, it is up to you provide proof of your position. I'd love to see the test results from the labs!

By this logic, I can claim that I've proved that smoking doesn't shorten your life expectancy because my grandmother smoked for all her adult life and she lived to age 80. By this logic, I could argue that my dog's saliva protects me from leprosy because she licks my face every day, and I don't have leprosy! I think you can see where I'm going with this. Personal experience isn't data, and there are too many confounding factors to declare that after a few personal experiences that a controversy is resolved.

I'm eager to see the tests and studies you can send me as I see you've commented on essential oils being preservatives! I've got a lot of reading to do this weekend!

solquartocrescente said...

I agree with you that GSE is not a very good preservative, but the point I was arguing is that it has SOME preservative effect, which is different to say that has none. But I understood your point. Pratically speaking this is far from being an acceptable broad spectrum preservative.

To make it short, creams preserved with 3% GSE were incubated with bacteria and fungi. After 1 week, bacteria counts revealed less than 100 cfu, but molds were detected at substancial levels. So my point is that GSE protects against bacteria but not molds (for example, Aspergillus). This extract had not additives.

Actually, other plant extracts also work as preservatives but again they are not broad spectrum. For example, olive leaf protects against some bacteria and molds (including Aspergillus), but not all. Here, for example, one can find interesting to combine GSE and Olive leaf to cover the spectrum that the other does not cover.

The same thing goes for essential oils. They preserve against certain bacteria and fungi, but not other species. For example, Tea tree kills most gram - bacteria but not gram +, while manuka oil kills most gram +. Both already have microcidal effect at concentrations of 0.1%.

I cannot share the results of my studies yet, but this is no problem, because everyone can read many scientific published papers, that are available on the internet, describing these effects in detail. You can see which plant extracts and oils protects from which microorganisms and at which concentrations. Then you can play with combining them to achieve full spectrum.

Some of those scientific studies are freely available, others you can only read the summary, the details are only available through a paid service (I have access because I have worked as a microbiologist on the past - so that's why I am fully aware of microorganisms, how they grow, how their growth can be inhibited, etc)

For example, this is a study showing the effect of lemongrass at 0.1% in inhibiting Aspergillus mold, which is one of the most common
Obviously in each different formulation, the need for preservation will be different, so percentages requirements might be lower or higher.

I understand that essential oils have the disadvantage of strong scent, so plant extracts might be even a better choice, and there are many possible (see just some here there are way more)

Because there is so much information available, the best is go to and just type for example "fungicidal essential oils" and start from there

Susan Barclay-Nichols said...

And I'm arguing that it doesn't have a preservative effect. I can't find any studies showing that unadulterated GSE can preserve a product. I have seen studies that show that it can offer some anti-oxidant properties to a product, but none that show it can offer preserving powers.

Having worked as a microbiologist, you know what constitutes good science. You know that you have to back up what you say, but you still haven't provided any information or links to good studies that make your point, which is baffling to me. If you are conducting your own study and can't provide any information on it, then it's not really valid for this argument at the moment.

We are aware that ingredients like tea tree oil have antimicrobial properties - I've written about this many times - but the science isn't there to show that those antimicrobial properties can protect our products. (See the other post in which we're both commenting...)

Thank you for the link to the study on lemongrass essential oil. I believe I quoted a number of similar studies in my post on lemongrass essential oil the other day with the same kinds of results. But these results do not demonstrate that lemongrass essential oil would work to preserve our products.

Here are the two points you are trying to prove...
1. That GSE has some preserving power.
2. That some essential oils can preserve our products.

You have provided information showing that some essential oils have antimicrobial properties, a point that isn't in dispute. You have failed to provide any studies to make your two main points. I can't say this often enough - it is up to you to provide links to studies that back up your position. It isn't up to me to spend my time trying to prove your argument, and if your next post doesn't contain a bunch of links to make your case, then I'm considering this argument done.

As an aside, I think the article you sent me from the Cosmetics Business magazine is an interesting read. The problem as I see it is twofold...again, they quote that things are antimicrobial neat on our skin or in vitro, but there's no claims that we can put these ingredients into a lotion at this many percent to preserve our products. (Which is the eternal dilemma - how to find a natural preservative?) And two, if these are emerging trends, why aren't they being used six years later? You're proving the point that essential oils and natural extracts can have antimicrobial properties - again, a point that isn't in dispute - but you aren't proving that they work in our products. (Take a look at the honeysuckle extract debate to see that being a natural paraben doesn't mean you can work well as a preservative!)

I look forward to seeing your research!

solquartocrescente said...

Susan, I will not seek forward to try to prove my points or experiences because I do not interest in having my points proved to others.

I only came here to share what I did find on my experience, because it might be useful for some readers. As I am aware many do not have access to microbiological tests as I do.

In my own experience, GSE without additives, protected my creams from bacteria, but not every mold (anyhow most preservatives never protect against everything and have to be combined).

But again I am not here to prove my points, because that is not my goal. I know that you do not consider GSE as a preservative, so this information is of no interest for you. But any reader that is interested in working with GSE might read what I already wrote.

Hope you understand that I seek no further to discuss our different points.

I am just here to read your blog and comment/ share experiences/ learn from others.

Evik said...

Dear Susan,

I have no opinion on the GSE as an preservative so far, I know it is controversial, and am not trying to prove you it is a preservative, I just wanted to point out this study as a material for discussion:

The study is from 2004 and does NOT investigate commercially available GSE - where I thing might be the problem of all the studies and the confounding factors of added preservatives and other not naturally present compounds. They do study only their own ethanolic extracts, with no ad-hoc conversions into quarternary compounds (described e.g. here:

The conclusion is

Results reported here contribute to the knowledge of the antimicrobial efficacy of GSE. It has been established that the fully natural ethanolic extract of grapefruit seeds
and pulp affects the tested bacteria and yeasts remarkably, but exerts less antimicrobial efficacy compared to some commercial preparations reported in the literature.


Robert said...

It is very interesting which is the less chemical preservative ? Could we put a mix of natural products which have preservative effects so we could put less chemical in our products ?
Thank you and keep up the good work :-)

Susan Barclay-Nichols said...

Hi Robert! I've written my thoughts on your question in Monday's Wonderings. I think what you're thinking about is called hurdle technology?

veronica said...

Hi Susan,

I noticed a lot of handcrafted skincare brands such as Laura Whole Plant Organics and EdenSong skincare are using plant based / "multifaceted botanical" preservation systems. They also claim it preserves their products for up to a year. Do these actually work?

Susan Barclay-Nichols said...

Hi Veronica! I looked up Laurel Plant Organics and they use potassium sorbate in some of their products. (An "untraceable amount", whatever that means.) They don't know what they are talking about because according to their FAQ, they think that preservatives are the same as anti-oxidants. Now I noticed that most of their products are oil based, so they don't need a preservative, but this kind of statement on the FAQ makes me worry quite a lot. Expensive products and not preserved properly. Eek!

Eden Song is missing some ingredients from their products, like emulsifiers. They have a lot of products that don't need preserving, and the ones I saw that did, had "radish root extract", which is a way of saying they're using Leuicidal preservative.

Interesting that both of these companies have a lot of products that wouldn't be considered lotions but anhydrous products, like their butters or "lotions" that don't contain water. You don't need preservatives for these products.

Okay, to get to the question, I think they are probably using "natural" preservatives like NataPres, Leucidal, and Advanced Aloe Leucidal and calling them by different names, like radish root extract. These could be effective if they are using them at the proper rates and using hurdle techology to make sure their products are uncontaminated. There are some reports, though, that Leucidal isn't working as well as some would like, though....

Ivona said...

Hi Susan!
I find your article very interesting. What do you think about "100 Percent Pure" cosmetics? I understand that they use a patented system for preserving their products...a combination of thyme, oregano, lavender and some other plants. I don't see this patented system mentioned in all of their products (if it preserves their products it should be used in every product that need preservation, right?). I don't quite understand if this combination is/could be allergic for the skin...what I mean is if you use so many essential oils in a product, wouldn't this make the product a potential allergenic one?

Is there any way to avoid these essential oils and use plant extracts like thyme powder or lavender powder - do they still have the antimicrobial effect? Do you know any studies on this?

Thank you!

Susan Barclay-Nichols said...

Hi Ivona. I've written about Pure before - check out the post here - and I know I've written about their preservative system recently, but I can't find the post. I don't trust these preservative combinations, but in the end, they almost always end up being the colloquial names for something that has a more appropriate INCI, like sodium levulinate for basil oil. I don't trust this company - sorry - as they don't follow the INCI rules like everyone else.

As for allergies, essential oils can trigger sensitivities or allergies, so I'd be very careful if you have any concerns!

Dedra Jenkins said...

Hi Susan. Thanks for all the helpful information you provide. It is most appreciated. I have a question about a particular product. It is called Fig and Yarrow Underarm Lotion. I noticed that this product didn't have any preservative listed. I am sensitive to certain things so I emailed to ask them if their product had any preservatives. They replied saying it was "naturally preserved". Given what you have written, I am not sure what they could mean by this. Is it a law or rule that you must have ALL ingredients in a product listed? Could they simply be leaving out this information? I also read on another site some time back that many companies "hide" the fact that their products have preservatives in aloe gel. The article said that aloe gel cannot be produced without using a preservative, therefor any product that has aloe gel likely already has enough preservative and you may not need to add additional preservatives due to this. Could it be that they are getting their aloe gel from a supplier who already is using a preservative, therefor they do not have to use any additional preservatives? Or, because there is no water in their product, perhaps they don't need a preservative??? But I thought if a product has aloe, you HAD to have a preservative??? Here is their list of ingredients. What do you think is happening here? I would like to order their product but would also like more clarity on which preservative, if any, they are using.

Aloe barbadensis (aloe) gel*, Hamamelis virginiana (witch hazel) extract*, Zinc oxide, Cocos nucifera (coconut) oil*†, Sage extract (neutral cane alcohol*, Salvia officianalis*), Glyceryl stearate, Sodium bicarbonate (baking soda), Cetearyl alcohol, Citric acid, Sodium stearoyl lactylate, Glycine max (soy lecithin)*, essential oil of: Aniba rosaeodora (rosewood).

Any insight you can give would be most appreciated. Thanks so much!

Susan Barclay-Nichols said...

Hi Dedra! I went a bit nuts answering your comment, and it turned into two posts. You can read the first one on Thursday, the other on Friday.

Here's the link for Thursday, September 15th, 2016. (It won't work until then...)

Thanks for the great question, and thanks for the inspiration!