Essential Oils Testing — Is it Reliable?

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If you haven’t noticed, there has been a lot of hubbub on the internet about everything about essential oils these days.  There are loads of blogs telling you that their oils company is the best one and my blog series about my search for the best essential oils company has been extremely popular.  Often, in posts about oils, you are urged to sign up with a direct sales company to makes money selling oils, or at least to get your oils for free.

There are essential oils remedies, recipes, “Medicine Cabinet Makeovers,” information about antibacterial essential oils, and testimonials galore.

worker getting essential oil from an amber bottle

One thing that comes up over and over again regarding essential oils, however, is GC/MS testing and in this post we’re going to talk about that in more detail.

We’ll learn:

What GC/MS testing is
What GC/MS tests tell us
What GC/MS testing’s limitations are

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What is GC/MS Essential Oil Testing?

GC/MS testing is Gas chromatography–mass spectrometry.  

What does that mean, you ask?

Basically, here’s what a GC/MS test does:

1.  The essential oils are injected into an apparatus with a tube.  The tube is coated with material that has different affinities for different chemicals at different temperatures.

2.  The temperature of the apparatus is gradually increased.

3.  The oil vapors are moved through the apparatus to a detector at the end of the column.

4.  The detector responds to the vaporized parts of the oils by printing out proportional peaks on paper.

5.  The height of each peak corresponds to the amount of each component of the oil.

6.  Components are identified by the time at which the peak prints out on the paper.

7.  The data for each oil can be compared with standards, or “fingerprints,” for each essential oil to make determinations about purity and other qualities of the oil.

Complex, but pretty neat, huh?

Basically, you get data about what components are in the oils and how much of each component there is.

S0–does that mean that if a company does GC/MS testing, that you can buy their oils and be sure you are getting “the real deal“?

And does it mean the if a company’s GC/MS tests come out within industry standards that you should feel comfortable using them?


Limits of Essential Oil Testing

Essential Oils Can Be Adulterated in Ways that GC/MS tests cannot determine.

a.  Adding synthetics: For example, if synthetic linalyl acetate is added to pure Lavender Oil, a GC-MS analysis cannot tell whether that compound is synthetic or natural, only that it is linalyl acetate.

b.  Heating: Some oils are heated to burn off more “herby” smells, as with Peppermint.

c.  Redistilling – Some oils are redistilled to make their fragrance more appealing.  I talked about this in this post.

d.  Blending of oils to Save Money or Get Uniform Smell

i. An “expert” might dilute a more expensive lavender with a less expensive lavender in order to sell the less expensive oil for a higher profit.

ii.  Sometimes customers complain that their oil “doesn’t smell like it did before.”  That can be a good thing, because oil smell should vary a bit–depending on weather, time of year, amount of water, etc.  However, sometimes oils are blended with other batches to avoid this kind of customer complaint.

I would rather have my oils vary in smell than have them mixed with other oils.

Read more in this post about many of the essential oil myths out there regarding essential oil purity.

Standards for GC/MS Testing Don’t Tell the Whole Story

When using the standardized guides and GC/MS testing, there are ranges that components of the essential oils are supposed to fall between.

For example, terpinen-4-ol is the active ingredient in tea tree oil that is supposed to be the most therapeutic.  When tea tree oil undergoes GC/MS testing, the compliant range for terpinen-4-ol is between 30 and 48%, and the “compliant range” for terpineol is 1.5 – 8%.  So the compliant range for the two combined is 31.5 – 56%.

However, since terpinen-4-ol is the most desired healing component of tea tree oil, some distillers have figured out ways to distill tea tree oil in order to have the resulting oil have a greater percentage of terpinen-4-ol.

Main Camp Natural Extracts claims to be “the purest tea tree oil in the world.”  Now, I don’t know about “purest” but they do have some pretty strong tea tree oil.  Their terpinen-4-ol + terpineol is a minimum of 75% (according to a document on their site) and it typically is over 80%.  That clearly is well outside of the GC/MS guidelines.

So Main Camp’s oil would not test compliant with GC/MS testing, but it seems to be a valuable tea tree oil, nonetheless.

Depending on what you think about the method they used to extract more terpinen-4-ol, you may or may not want that oil, but this example just goes to show that having more of an active ingredient in an oil might make the oil more therapeutic without it testing “compliant” on a GC/MS test.

Sacred Frankincense is another oil where this is done.  Some distillers can apparently tweak the advanced tech extraction that will just extract greater proportions of the anti-cancer component in frankincense oil.  The resulting oil won’t test compliant with GC/MS testing, but it is technically “more therapeutic.”

GC/MS Testing Does Not Directly Reflect Soil Quality

GC/MS testing only tests volatile (those that evaporate rather quickly) chemicals.

Such testing can’t make allowance for whether or not a plant was grown in soil with quality nutritional components.

We all know that organic farming practices yield higher quality produce.  As such, one would expect that the same would hold true for essential oils–we would expect that essential oils grown in high quality soil would have more therapeutic benefits.

GC/MS Testing Does Not Test for Many Environmental Toxins

Since GC/MS testing can only test for volatile chemicals, it won’t test for heavy metals or other toxins that are heavy.

What kinds of toxins won’t show up on a GC/MS test?  (I don’t want any of these in my oils–ick!)

a.  Trace amounts of iron from an iron distiller might break off and end up in the oil.

b.  Radiation

c.  Heavy Metals

d.  Heavier Pesticides

e.  Pollution components

f.  Heavier chemicals from fertilizers

There are lots of things that could be in essential oils that I know I don’t want on my body, because there are lots of oil-soluble chemicals, pesticides, etc.   Of course, you might think that a small amount of toxins might not be a big issue, but over time it can accumulate, especially if you are using the oils frequently.  And with our toxic environment, why add anything to the burden you and your family are already under?

Also you might be purchasing organically grown oils, but if the farm is next to a heavily-polluted area, the plants will likely be polluted.

Something to think about:  Would you want an essential oil that was grown on toxic waste that passes the GC/MS reference standards, or would you rather have an essential oil grown organically that does not meet the testing standards for some reason?

I know which one I would want ;-).


Remember back in my series about my path to choosing the essential oils company that my family would use?

Along the way, I heard all kinds of things about testing and certifications, some of which the oils companies made up themselves.

Well, testing is important.

But so are a lot of other things.

Here are the things that I recommend you look for in an oil company:

Signs of a Quality Essential Oil Company

1.  Experience
2.  Purity
3.  Plants grown in indigenous locations
4.  Organic and/or wild-crafted when available
5.  Most plants are grown in remote locations where no pesticides, herbicides, or harmful chemicals are used and only natural fertilizers are used.
5.  Reasonable shipping prices
6.  Reasonable pricing
7.  No solvents used
8.  No artificial oils sold
9.  No adulterating (no heating, blending, adding or further distillation of oils)
10.  Sourced from Small Farms, if possible
11.  Common Sense Approach to oils – no “over-recommending” of essential oils use.

There are so many essential oils companies to choose from that it can be hard to know where to go to buy quality essential oils.

You can go to this series to see the company that I went with when trying to find the “best” essential oils.   You can also skip to the final post here.

Want More Information About Essential Oils?

Free Essential Oils Report and VIP Newsletter Access

Also, if you go and grab my Free Report on 10 Things to Know About Essential Oils Before You Buy, you will not only get more myth-busting essential oils information, but you’ll get access to my VIP newsletter as well–complete with updates, great healthy living offers, of course new posts on essential oils, and more.

10 things you need to know about essential oils report in ipad

What do you think? I’d love to hear your thoughts!

(The top image is the copyrighted property of 123rf limited.  They are a contributor or licensed partner and their image is being used with permission under license and cannot be copied or downloaded without permission from 123rf limited.)

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  1. I’m a little bit confused the article stated that GC/MS doesnt guaranteed a lot of quality but that’s all tests I found so far on RMO web site. Plz help me up how did you conclude the quality of RMO oils if there is no tests posted such as IRMS. In nature, the carbon isotope.

    1. Hi there. I stated that the GC/MS doesn’t mean everything–but it is, of course, very important. Does that help?

  2. Adrienne,
    Reading your articles were fun! I found a bit of a “kindred spirit”, towards you and your well written articles.
    I’m a Huge fan of doTerra Oils, but didn’t realize how much they didn’t (not all) work for me until I read your comments on them! I thought it was, “just me”. We all want so badly to believe in something that we tend to let other things slide. Unfortunate but true, one tends to trust less and less.
    I bought Ancient Apothecary Oils form the infamous Dr. Axe sight. He seems legit, right? <~~ Yes, that’s what they all say.
    Thank you for all the hard work, time and interesting information.


    Dianne Foster

    1. Hi there–nice to “meet” you! I appreciate the kind words. So you are saying that doTERRA didn’t work well for you? I think there are a lot of things to consider about a company–purity, marketing, knowledge base, and the way that a company deals ethically with affiliates, etc. It’s a hard thing to discern on all levels. I hope to revisit this topic again hopefully in the near future. Stay tuned!

  3. Hi. I would love your opinion on this company called Gurunanda. I have ordered from a different one also called Godesana but they are very expensive. I recently ordered some oils from Gurunanda and then found your website on all about the right oils. If you could give me your feed back on this company to see if I should stay with this company or go with Rocky Mountain Oils. Which I was considering long before I went with this company. Thank you so much for all of your information.

      1. the article does not mention Gurunanda by name. curious why the questioned is answered but no answer is given.

        1. Hi Bonnie. I have seen a number of companies that had 3rd party tests done on their oils and they failed. I haven’t been able to validate the results but they seem to be trustworthy to me. There are quite a few of these. I don’t just look at GC/MS testing but it’s a huge factor for obvious reasons.
          The topic of why I don’t recommend a lot of companies is very complicated and I do hope to revisit this topic soon. Stay tuned! You can subscribe here if you like–more EO articles coming soon!

  4. Any chance there is a way to do testing of your own? Is there a company that you can send oils to (as an individual, not a business)?

      1. Hi Adrienne, great post. What is the name and location of the lab that tests these oils. I want to get an oil tested. Thanks

        1. Hi and thanks. There are a lot of them out there. They are about $240 to get one oil tested. I personally trust Phytochemia but there are other good ones out there.

          1. Thank you Adrienne. It seems like this lab is in Canada. Can you share some labs in the USA that do similar testing?

            Is there an email address where I can reach you directly?

            1. Hi there -I’m sorry but I don’t know that. I’m sure there are some. Perhaps contacting them and then asking what they do or asking for a referral is good idea. I am available at adrienne {at} wholenewmom {dot} com but I’m extremely busy right now and prefer to keep communication on my blog if at all possible at this post. I don’t mean to be avoiding anything but I am managing comments here and when I get them via email and FB it gets to be too much. At least here the contribute to the conversation for everyone. Hope that makes sense.

  5. Great research! Your work literally made me jump off the MLM YL bandwagon I was strongly considering joining as I was reading your blog last week. I looked into RMO and ordered my first one, their website and info/transparency seems legit. I opened tabs between RMO, YL, and DT and found RMO was cheaper or the same as their wholesale price! So I like them so far and I don’t even have a bottle yet! Sadly I recently bought a bunch of oils from TJ Maxx and Amazon before getting more into it…. bleh. I guess I’ll try to use these quickly to get better ones lol.

    Not sure if anyone else has asked you this but I’m sure you looked into Edens Garden and what do you think? They seem very close to RMO, but the only difference I can see is they are less expensive.

    Thanks for your thoughts!

  6. Looks like they do not carry Frankinsence. Do you use it and if so, what company due you purchase from?

    1. I’m sorry but I’m confused – what company are you trying to buy from as the companies that I work with do carry Frankincense. Please let me know. Thanks!

    2. Hi,
      I shop with a company that has been around for 30 plus years. They do carry Frankincense, and perform all these for quality control:
      GCMS testing
      Chirality testing
      Heavy metal/pesticide/herbicide testing
      Organoleptic testing
      Optical rotation and refractive index testing
      Specific gravity testing
      Microbial testing
      You can email me if you like 🙂

      1. Hello there. What do you think about the fact that Melaleuca has artificial ingredients (colors and fragrances) in many of their products? I am very curious about this. Thanks.

  7. Thank you for the extensive research. Do you by chance have information on Saje Natural Wellness products? It’s a retail company. Thank you – I’m comparing between RMO, doTerra and Saje ??

  8. Excuse me, the main way that essential oils
    Medicinal Quality essential oils are found directly from the grower and are not sold on the retail market because, they are full potency medicinal quality essential oils which can and do create a profound change in the same manner as any other medication. Therefore, if not properly trained, the general public could be harmed through improper use. Therefore, these products are not marketed or sold to the general public or through a “distributor”. In other words, you cant buy a book on aromatherapy and become a healer. You cant purchase essential oils from one company or two and utilize those oils for a profound healing change because, the oils are stepped on over and over again until very little of the original essential properties remain. 1) In order to protect the public from wanna be new age healers who might accidentally do harm to themselves. 2) For huge mark up while claiming to be the real thing. Use of medicinal quality plant based oils is in fact the same as medical treatment. So please, don’t blame the “essence” for your inability to cause a profound change by your use of these products. These are not the oils we use in alternative medicine. Food grade quality is not medicinal quality. The reason for testing is as follows: Lavender oil pure essential oil made from the petals of the flowers is very expensive and has a distinctive smell or “nose” in the same manner as wine. However, the leaves or stems of the plant also contain similar but, not exact properties as the petals of the lavender flower which can be utilized to mimic the smell of pure lavender oil. Additionally, other plant leaves for example posses a similar chemical make up which can be and most often is utilized very cheaply by comparison to lavender flower petals to manufacture the pseudo-essential oils being marketed today. The general home maker who is not a connoisseur of lavender oil will not recognize the difference and The Beauty/ Make Up Industry has made sure they may legally call this product “pure essential lavender oil” in the same manner as food manufacturers can say that foods containing monosodium glutamate have “natural flavoring”. The testing which you refer to is very expensive and is necessary in the manufacture of both products in order, to make sure you have the correct amounts of the oils from different parts of different plants to successfully mimic the smell of pure Lavender oil. In addition, in production of essential oils and essences there are other chemicals utilized such as alcohol. Therefore, I suggest you purchase your favorite oils from several companies and do a comparison of them yourself. Choose your favorite based upon packaging, price and scent as well as, strength of scent which can be diluted. Do not expect you are getting a “natural remedy”.
    If the company does not have a written guarantee on the bottle that your oil 100% medicinal quality plant based oil. It is not. Furthermore, internal use should not be considered and be advised that food grade quality oils may still damage, burn or hurt the skin, eyes and mucous membranes. Thank you.

    1. Hi there. Thanks for reading and for commenting. So are you saying that the only truly pure essential oils that are useful for their healing properties are bought directly from a grower? And that on the bottle it will say “100% medicinal quality plant based oil”?


  9. You are truly amazing! Your time, research and dedication to finding the best EOS for your family is commendable and I thank you for sharing your research. I stumbled upon this blog today because I have nothing better to do but lay around due to a torn Achilles tendon – yay. I used Young Living for about a year and was very pleased with many of their oils. I even signed up and purchase the kit, but I found that it was truly expense that I couldn’t afford. I did a little research (not like you by any means) and found Eden’s Garden. I do like the majority of their oils but I would like to hear what you specifically have to say regarding the company and the oils that they provide. I’m sure you’ve been asked this repeatedly and I apologize if this question is redundant.

  10. Hi Adrienne,
    I just stumbled upon some different essential oils called Numa essential oils through a Dr. Axe which is a nutritionist and was wondering if you have heard about these oils?

    1. I have. Have you seen their claims that they are the only pure oils out there? That there are no other pure retail oils and that theirs are the only USDA organic essential oils on the market? I am finishing up a post on oil purity. I would highly recommend that you stay tuned. You can subscribe to my newsletter here to so you won’t miss it:

      Thanks for reading.

  11. If I understand correctly, you were purchasing Young Living oils but switched to Rocky Mountain Oils. Why did you switch companies? Thank you for your time.

  12. I stumbled on your blog today and it was very interesting to ready about your research on essential oils. I have tried a few even the YL oils. When I saw what company you decided to use I went straight to their website and saved it to my favorites. I think I’m going to order some of the same ones I got from YL and Miracle oils and see what differences there are in smell etc.

    1. Hello Marti. Thanks for reading and commenting. I would be interested in what you think, but smell is not the only / best test for purity. I am actually working on a new post about essential oil purity that you might be interested in. Hope you’ll stay tuned for it!

  13. Have you looked into miracle oils? Also not sure I understand. Are u still recommending RMO for best EO’s even though they are diluted with coconut oil? Dotterra doesn’t do this. Or are u saying RMO is a great company only if we want to start up a business aswell. Can u tell us one other company u recommend to get best EO’s besides RMO?

    1. Hello there. Yes, I did look into that company. RMO dilutes some of their blends with fractionated coconut oil to keep the price more reasonable. When the company was originally Native American Nutritionals the owner told me that many of his customers wanted it that way. I hope to write more about oil dilution in the future. I have another company in this post that I recommend. I hope to come back to this issue in the future with more guidelines, etc.

      1. What are your thoughts on plant therapy and or mountain rose herbs I need to know how medicinal they are for taking them by capsel currently using do terra but getting way to pricey with job change I also use topicality and diffuse please let me know thank you so much…

        1. P.s. wanted to know if and what kinds of herbicide/pesticides GMOs ect in these oils or anything harmful that may effect the medicinal properties, do terra tells me it’s all fine that’s why there oils are priced? higher because of the extremely high priced Insurance they have because of the ingesting them properly. Any help would be fabulous

          1. doTERRA said that they are paying more for insurance b/c they are recommending internal use? The post on purity that I linked to should tell you about pesticide issues.

        2. Hi there. I can’t recommend taking essential oils internally without the guidance of a medical professional or aromatherapist. There are too many risks. This post should help. and you might wish to sign up for updates as I will be writing more on oils in the future:

          Medicinal isn’t a quantified term in the Essential Oils field. It’s about purity and meeting GC/MS standards. Some oils will have more of a certain part of the oil but that will mean different things depending on what it is. It’s important to have pure oils for topical and diffusing as well. Mountain Rose Herbs did email me stating that they had found synthetics in some of their oils — I assume that they have taken care of this but it just underscores the importance of testing each and every batch.

      2. I bought a kit from them that all have been pre-diluted. I actually love it as I can just pick them up and apply them to my body as needed.

  14. Hi there! I have a friend who recently got into YL and I’m interested in how their tests compare. On their website they claim to do IRMS tests which I’m not sure if are comparable to GC/MS testing? I figured since you’ve been researching all of this you might have an answer 🙂 Great work! Truly commendable. I’m looking into RMO too since you’ve recommended them.

    1. Hello there. I’m doing more research into this but this is the response from an expert in the field:

      IRMS is used for isotope testing, usually to ascertain the geological age of something.

      In the context of essential oils, this can reveal when a petroleum-derived synthetic has been added to an essential oil, as petroleum will show up as millions of years old. Any time this happens with an essential oil it’s a red flag.

      IRMS is not an alternative to GC/MS, but may be used in addition.

      Stay tuned…more on oils to come!

  15. Hello:
    would you expect to see an essential oil that is labeled for external use only i.e. massage to have preservative efficacy testing performed on it?

    1. Hi there. I’m not sure that I follow you. Are you asking me if that essential oils should or could be tested to see if it’s an effective preservative? I personally don’t currently have confidence in the preservative capability of essential oils but I am looking into it further. I don’t see any issues w/ labeling of EOs as being an issue in this regard. It is sometimes done for liability purposes and sometimes b/c the company doesn’t advocate the use internally. Of course purity is a concern regardless of labeling claims.

      1. Please, do not experiment with ingesting these products. China has flooded the market with so called “massage supplies” these are not what was sold on the retail market in the 1980’s. before the massage therapy and bodyworker community was destroyed by the salon, make up and beauty industry., I never buy my products from a corporate manufacturer. take care and stay safe. :Great research. please see my longer post above.

  16. I really appreciate all the research you have done. i have been searching for the best essential oils company and your article has really inspired me. I have tried Rocky Mountain Oils and like the single ingredient oils. I have been noticing many ads for their blends on Facebook and am distressed to see most of them are diluted with fractionated coconut oil anywhere from 60-95% and still carry a pretty big price. They don’t hide this fact but don’t jump out there and tell you either. They still recommend carriers used with these and that seems a little odd. They have really been pushing these blends so I am not as enthused with this company as I was. I would rather have the choice of what carrier to use and I am sure shelf life is affected when diluted so heavily. Thank you

    1. Hi there. Thanks for reading and for the kind words. As for the carrier oils, the company says that they do this to bring the cost down b/c of the pricier oils and to make them more easily usable, though of course for topical uses you would want to dilute them further. However, it does make it easier. I see other companies do that as well. I will ask about shelf life for you. Might affect it but the EOs might prevent that. I hope to get back to you soon.

    2. Hi Cindy,
      I’ve found D?TERRA oils to be the best in quality and purity
      Undiluted unadulterated and free of chemicals and pesticides
      You can add your own carrier oil.

      1. DoTERRA Oils have some blends that have FCO in them – and some of the single oils are available with FCO. They are called the Touch oils. I love and use DoTERRA’s oils daily – sometimes undiluted and sometimes with the FCO. I do believe they are the best tested oils in the market for purity.

  17. Hi there,

    I love all the research you have done. I am not sure if you would be up for it, but I would really like to talk to you on the phone. There is an essential oils line that I would really like to see how it lines up to your standards. Please email me and we can set up a time to chat in private. Thanks.

    1. Hi there. Thanks for reading. I’m sorry but I can’t do phone consults. You are welcome to leave the name here and I will respond the best that I can -thanks!

  18. Hello, I’m wondering if there is a reason you choose to buy your oils from a different company if you are an NYR Organics consultant? I’m considering becoming a consultant and was just curious. Thank you!

    1. Hi Sara.

      I looked at the oils years ago – and did consider NYR at the time and frankly should have gone with them then as at least an option. They don’t, however, have a very broad offering, though they are apparently looking to bring more to the US. I think their purity and quality is great and their focus on sustainability is something that is very important to me. But I went a different direction to give myself and my readers the opportunity to source more oils.

      Then early this year I was on the hunt for a new personal care company since the one I was with had numerous ethical issue. I went back to NYR and am very very pleased with their personal care. I am happy about their sustainability, but they do not produce batch testing results at this time and that is something I really want.

      Update 2/5/18: Now the company that I recommended at first has added some organic oils to their offerings and should be getting more so that is a new thing to consider as well. Plus they have batch test results.