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!

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  1. I jut need to know where I can get the best EO’s or a new cancer patient. I’m looking for roll ons and for diffuser style and want the purest, most helpful for her. Cost would be nice but really just want to help a fried make it thought a tough time with a little help. I know people say their are cancer kits but I have not found them and really just want the oil that will best help her since she starts surgery Monday. I guess I’m saying separate oils or a kit both would be fine but not sure what would be the best help for her to make cancer a little more bearable. I do want a company that has good customer service in case we need to get more information in the future, help with any orders, and reasonable shipping times.

    1. Hello and sorry for the late reply. I had a backlog of comments to get through. Sorry about your friend. I can tell you that if you are looking for roll ons then it depends on what you are looking for.

      As for a diffuser there are some with the company in this post that would work. This company only has roll ons for kids, however. I am sending you an email as well – hopefully I can help you.

  2. THANK YOU for your time and educating all of us mom’s and daughters who are caring for family!
    I do by many oils from different companies and do tests oils against each other with my family as well.
    Lately we have been using a muscle blend from Eden Gardens and wondered if you had found any info on them in your searches?

    1. Hi Lenora – thanks for the kind words. I am doing more work looking at other companies so that I and my readers have other options. I know that it is very important to have a GC/MS test with a chemist’s signature on it. Does Eden’s Garden have that?

  3. Thank you for your article…very informative. RMOs website says nothing about being organic? Do you know something they are not showing the public? Thanks.

    1. Hello Susan.

      When I first went with NAN, they were almost all (or all) wild-crafted, organically grown, and certified organic. When RMO bought NAN, things changed and they were looking at purity over organic. They just redid their site and the growing conditions aren’t on the site now but they do have more conventional oils than before. They told me that they are prioritizing purity over organic and that sometimes the organic price is prohibitive. They are sorting through how to indicate on their site what the growing conditions are so I am awaiting that. I am talking to other companies as I know that my readers have different desires and priorities, but I am still in the middle of that. For now, if organic is a priority to you, I can recommend Neal’s Yard Remedies. They do not have the selection that RMO has, but they have a good selection of organic oils and they do GC/MS testing on every batch and they have a stellar reputation. You can read more about them here: and their aromatherapy section is here.

      I hope to have more to share about RMO as well as other options in the future. Thanks in advance for your patience. Feel free to ask if you have more questions.

  4. Can you comment on Florihana or Hopewell (heritage) oils? I’d love to know your thoughts. Also, carrot seed oil at RMO is $30 some odd dollars and $9 some odd dollars at Eden’s Garden…why do you think there is such a big difference?

    1. I am working on talking to other companies to see what they are doing, however I did look at both of these companies and decided against them. I’m doing what I can to find out what is going on but it is hard to tell. I spent about 3-5 hours on it this week already (maybe more). Stay tuned.

  5. Was just wondering what you discovered as to the purity of butterfly express oils. I was first introduced to ess oils with this company and have always seemed satusified but am wondering the true integrity of their oils?!
    Thank you

    1. I am working when I have time to check on other brands. I didn’t go w/ Butterfly Express when I did this series for several reasons. Companies change what they are doing and there are so many out there. I’m doing what I can to figure out more and share with you all when I can, but it takes hours just to look at one company…or more. Please stay tuned. Thanks!

  6. Thanks to your recommendation I ordered RMOs and so far I love them! Is there an affiliate program and education program with RMO? I’m asking you since I probably wouldn’t have found them and trusted them without your posts.

  7. Until recently I have always used Native American Nutritionals, it seems they are now Rocky Mountain Oils. So I am feeling good about getting oils from RMO now that I know I’m not just making that choice because it’s the only choice I have.

    Thank you!

  8. I didn’t see mention of “Be Young” essential oils. I have read much about ess. oils and reviews and heard they were by far superior in their purity.

      1. I’ve never heard of Be Young until seeing it here on your blog. Could you share what your reasons are for not going with them?


      1. I’ve just recently heard about AMEO as well. Could you share what your reasons are for not going with Ameo?

  9. thanks for all the interesting and well researched information. not an easy choice with all the companies out
    there claiming to have the best oils. you did the work for many of us and its greatly appreciated. I will be trying
    rocky mtn oils, (as long as they’re not a mulit level business)

    1. Hello Marilyn- thanks for the kind words. Rocky Mountain is not a multi level business. To be fair, I don’t think that MLMs are all problematic, but I think that many are as they make exaggerated claims about their products and have markups that are just too high. In other ways it is a great way to have a personal touch with a business. But in the oils world, most of them I do not care for. Would love to hear what you think about them!

  10. My question is about the essentials oils sold in stores like vitamin shoppe, should I stop purchasing from them, they sell NOW, nature’s alchemy, plantlife, and aura cacia. Are any of these good oil companies to buy from, does everything have to be ordered online?

  11. New question: I have done some research and know that if a pure EO freezes there is bound to be additives and I’m trying to use as pure as I can get… What does your research show for freezer tests? Excluding peppermint as I know there are many properties involved and it is nearly impossible to freeze any peppermint EO..

    1. I have heard from Rocky Mountain Oils that this is a gimmick – all oils will freeze but their freezing temperature is very low. Even peppermint will freeze. Hope that helps.

  12. Question? What about the stated “we own our distilleries”? therefore “we have control over purity”?

  13. Thanks for this very helpful article. You address a number of concerns I have and it’s refreshing to see this kind of thorough analysis. For myself, an aromatherapist, I use Robert Tisserand’s 2nd Edition Essential Oil Safety to check on any issues an oil might bring up. Also, the guidelines in the aromatherapy course I took emphasize that essential oils are not a silver bullet. Rather they are one item in a healing approach that first uses nutrition and lifestyle. Essential oils are so often used today as some kind of cure-all. As great as they are, they are extremely concentrated substances that require caution and knowledge before use. From what I’ve read, for example, the eucalyptus component 1, 8 cineole may be inciting CNS disturbances especially in children and individuals with sensitivities. The only eucalyptus oil that I know of with none of that component is Eucalyptus citriodora. So I no longer make the Thieve’s oil blend. I now use my own blend of equal amounts of Eucalyptus citriodora, Lavender off;, Frankincense (serrata) and Niaouli (melaleuca q.). Also, Tisserand discusses the many problems with citrus oils specifically their rapid breakdown. They are all cold pressed not steam distilled. This makes a huge difference in shelf life and safety, which I did not know. But it answered the question of why my formulas with lemon “essential oil” did not hold their strength. Thanks for your very helpful article. I’m a new subscriber. Also I am VERY grateful for the comment from Angie about Copaiba. I use Frankincense serrata for pain – blend with Argan oil. One source for my oils that meets all of your guidelines is Florihana – US distributor is Tropical Traditions. I use TT for the primary fixed oils for my artisan soap. Florihana has much more info available for the consumer than any other source I’ve dealt with. See Tropical Traditions website.

    1. Thanks for reading, commenting and subscribing! I am sorry for the delay in responding. I’ve been swamped and a bunch of comments slipped through the cracks. Hope to see you around again.

  14. Have you looked into Purely (formerly Simply Aroma) oils yet? I’d like to see you go through your checklist and verify the pureness of their oils as best you can.

  15. For Sharon looking for pain relief for her mother who is allergic to lavender, I would suggest looking up Copaiba. It has more beta-caryophelenes than even Cannabis oil for ultimately aiding in pain relief, and of course, with no THC as in Cannabis oil.

    Also, there was a comment about YL being an offshoot from DT. Just to set the record straight, it was the other way around. The founders of DT were all actually former employees of YL. Not that it has any bearing on anything else, just didn’t want misinformation left out there.

    Thanks for doing so much research on comparing companies and dealing with threats and negativity, it must have been exhausting to go through all that! As other lay people, all we can do is research to the best of our own abilities, and you have done an amazing job burrowing through it for all of us. I appreciate you taking on such an enormous endeavor.

    1. Hi Angie thank you for your information. I am interested to know where you bought the copaiba oil because I also do not want to take cannabis thank you very much appreciate hearing from you

  16. Hi Adrienne, I have read your blog for several years and I’m so impressed with all the research you do. I like to research everything also so I am very grateful for the extensive research you’ve done on EOs. I am desperately trying to help my 75 year old mother find relief for PHN–the neuralgia pain that can occur after having the shingles. She had shingles on her face in September and didn’t have much pain at the time. But for the past month she has debilitating pain in the back of her head and the cheek area. The Dr told her this pain could last for months or up to a year!! The Dr put her on prescription pain meds but they don’t help. In doing research trying to find a way to help relieve her constant pain I read about EOs and how they seem to help PHN amazingly well. It seems the best way to get relief is to use a diffuser and also apply topically and to blend several oils together. When used topically should she use a carrier oil or can she apply them full strength to her scalp and cheek?

    My question for you is: would you know what oils to recommend to help with PHN? My mom is allergic to lavender and some other flower type oils. And lavender is one that is supposed to be very effective for PHN. There are other oils that are supposed to help but I wondered if you could suggest which ones are the best and which ones should I start with?

    If any of your readers could recommend EOs that help PHN I would be so grateful. I have been so stressed and desperate to tears about this because it is extremely difficult to watch my dear mom in so much pain and I am helpless to relieve her pain. She is very brave but she is worn out from dealing with non stop pain. I am praying that you, Adreinne, or someone reading this would be able to help her.

    Hope to her from you as soon as possible.

    Thanks so much,

    1. Hello there. Thank you so much for your comment and your kind words. While I cannot provide a medical prescription, Nerve Repair and Relieve Me (back in stock this weekend) have been formulated to support the body and assist with pain relief. Cypress would also be a good support oil. You can also use the search feature on RMO or NAN’s website to see what other’s say. Hope that is helpful.

      1. Hi Adrienne, Thank you so much for the quick response!! I tried to place an order today and there seems to be a problem as my order would not go through. I attempted to do it twice but it would not progress to the next stage which should have been “thank you for your order”. I hope I wasn’t charged twice!! I am so disappointed because I don’t want to miss out on the 10% off and free shipping that ends today. I did contact them via email but their business hours are Mon-Fri so they won’t get my email till Monday morning. I am wondering if you or any of your readers have experienced this problem today when ordering from NAN? I hesitate to bother you with this but I don’t want to miss out on the sale and also they might be out of Nerve Relief soon…they are sold out of Relieve Me. Trying desperately to help my mom witH Shingles neuralgia pain. Thanks.

        1. Hi there. You are so welcome. And thanks for your follow up email telling me you got it to work. If you end up getting charged more than once just let me know (or contact customer service). I will be more than happy to help. I so hope the oils help her!!

    2. Hi, I too have been searching for answers for the neurological system as well as arthritis etc. I am thankful to find this post because it led me to safer oils. I have found something wonderful to aid in so many illnesses and it is called “Fossil Shell Flour” Diatomaceous Earth aka “DE”.

      It is important to know that there are many variables to DE and you must buy the one that says Food Grade OMRI, the best company that I found was PERMA GUARD. a 50lb bag is $50 something bucks.

      The good news is that in doing my research you can get it from Amazon or Ebay too. One of the best ways to use it that made sense to me is to add it to yogurt or pudding. One tablespoon in the morning and One tablespoon before going to bed. The reason for this is that many of us, especially those with illnesses do not realize that we have many, many parasites living within us that are destroying our immune system and good cells. Parasites love sugar/sweets and in adding one tablespoon to your yogurt/pudding they will rush to it as you eat and it will kill them off. Some consumers started out with less than a tablespoon but my motto is that for critically ill or super bad health it is best to “GO ALL IN”.

      I am in the process of getting my own bag for myself and my beloved cats and dogs. You will be amazed at All of the Uses Diatomaceous Earth has (kills bed bugs/mites/roaches, ticks/fleas) and you can use in conjunction to your wonderful oils as long as they are pure oils that can be used internally and exteriorly. Hope this helps…pls do your research. PS. many testimonials for growing Hair and Nails and improving Skin including getting rid of Acne. Thanks,

  17. Hi, I didn’t read through all of your comments on this article. I am a Doterra wellness advocate and I just wanted to mention that their oils are CPTG (certified pure therapeutic grade). This is the only EO company that has this label through the FDA. Their oils are produced around the world. They do their sourcing where the plant thrives best in it’s natural habitat. This will give you the best quality of your oils! I realize there are many oil companies out there but Doterra is truly on of the best! And you can use the oils internally! Of course not all oils are for internal use but on each individual bottle it will tell you the different ways to use that certain oil! Thank You for the great article and if you have any question please message me!

    1. Hello there, Christy.

      Thanks for commenting. In fact, doTERRA’s CPTG label is not through the FDA – it is something that they created themselves. I do not recommend using oils internally You might be interested in this series: Thanks and I’d be interested in what you think.

  18. Thanks for all the info. I have been doing extensive reading on EOs also and find the more I read the more confused I become. I have a medical background but as you know alternative medicine isn’t taught in conventional circles. On the other hand there are diseases for which there is no cure that giving alternatives is worth a try. Case in point is Alzheimer’s. I went to a talk given by a YL rep and she said YL was started as an outbranch from doTerra, so I found it funny that these were the two companies most outraged at your comments. I have spoken with several naturopathic who have recommended Nature Sunshine to me. I’m not sure if you have heard of this company. They are not inexpensive but source their oils from multiple farms as to be able to get the best herb at the time.I am just starting to use the oils so i can only speak for a few oils I have had good results with thus far.Since I am trying to help my mother who has Alzheimer’s I am interested in knowing I have the best and most effective oil before feeling that it is of no benefit. I am currently using Frankincense/sandalwood as a topical and diffusing rosemary/lavender/lemon. If anyone knows of other possible oils for injury to the nervous system I would love to know.

    1. Hi there – thanks for commenting! I can’t speak for Nature’s Sunshine. I didn’t look at them that closely, but I can ask about that sourcing. I don’t know how they could afford that though? As for nerves, there are blends on the Rocky Mountain / Native American Nutritionals sites that are for nerves. I can’t medically diagnose, but please just poke around.