Essential Oils Testing — Is it Reliable?

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Essential Oils Testing - Is It Reliable? So many people talk about the GC/MS test to show whether and essential oil is pure or not. But is it enough? I talk about that and what other things you should be looking at when trying to figure out if an essential oils has good quality oils or not.

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.

One thing that comes up over and over again regarding essential oils, however, is GC/MS testing.

Today we are going to talk about GC/MS testing in more detail.

We'll learn:

What GC/MS testing is
What GC/MS tests tells us
What GC/MS testing's limitations are

Stay with me–this is going to be very interesting.

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 about 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?


While GC/MS testing can tell us a lot, there are some problems with relying on these tests alone.

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1.  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 Eucalyptus Globulus or 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 on some of the Essential Oil myths out there regarding essential oil purity.

2.  The Standards for the GC/MS testing

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 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.”

3.  GC/MS testing does not determine 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.

4.  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 was going to be using?

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?


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Wondering about essential oils? I sure was. Get this guide to buying the best essential oils from a mom blogger who dug deep into the industry to find out what's really going on. Fascinating information including some real debunking that saved me a ton of time and money.

What do you think?
Please share your comments below.

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    Speak Your Mind


  1. 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.

  2. Audria Simmons says:

    Have you looked into now brand essential oils?

  3. karen walls says:

    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?

  4. 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.

  5. 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.

    • 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!

  6. 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?

    • 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.

  7. Emily Wood says:

    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.

  8. 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?

    • 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.