Essential Oil Adulteration Part 4

Understanding what types of essential oil adulteration there are and how they are discovered through testing, is an important subject for consumers. Armed with this information, you can carefully select your purchases from companies that offer testing that is thorough and reliable. If you haven’t read the previous 3 parts, we recommend you do so. If you’d like to read about the first 3 types of adulterations we’ve chosen to discuss, we have provided links at the end of this article.

The 4th type of adulteration we cover in this series are synthetic chemicals made from a natural precursor addition, which is a synthetic created from a precursor taken from a natural component. This happens when a company takes a natural molecule from an essential oil and chemically reacts it to create another essential oil. Synthetic precursors are easy to find using carbon 14 isotope testing, but using a naturally occurring molecule from another oil doesn’t show up on carbon 14 tests. This type of essential oil adulteration is very difficult to spot but can be identified using Trace Marker Analysis(1).

An example of this is using limonene from Orange oil to make carvone, then adding that synthetic carvone x limonene to another oil, like Spearmint. This type of alteration would pass carbon 14 tests without a problem, and the GC profile would look correct -unless you know what you’re looking for(1). This is yet another example of why it is so important to have knowledgeable and experienced analysts interpreting test results.

As covered in in part 3, carbon 14 isotope testing is a way to identify the origin of a molecule through the building blocks that make up the molecules(2). Trace marker analysis relies upon the experience and knowledge of those doing the analysis of the GC/MS reports. They must be experienced enough to differentiate between synthetic markers (showing as small peaks on the GC/MS report) and those that are naturally occurring. The small peaks don’t represent the number of adulterants added but are simply indicators of the adulterant(3). This again highlights the importance of using only the best and most reputable testing and analysis services available.

What can I do to avoid adulterated oils?
The best possible thing you can do as a customer is to find an essential oil company you trust. Even if you trust your company, be vigilant and watch to be sure they consistently offer test results you can access. Each test should be absolutely unique, not just unique lot numbers, but constituents should vary somewhat from one batch to the next. Your chosen company should use rigorous testing combined with the best analysis to will ensure pure, unaltered essential oils.

Stay away from oils that are unusually cheap. That can be a good indicator that the oil has been adulterated with a cheaper essential oil, carrier oil, or synthetic chemical. It should feel like a bit of an investment to buy oils. Some oils, like Lemon, are not very expensive, but others like Jasmine or Sandalwood, are very pricey. If you see an oil that is usually expensive for far less, it’s in your best interest to steer clear. A few examples of oils that should be more expensive (because of supply and demand) are Rose, Melissa, Helichrysum, Sandalwood, and Blue Tansy.

Links to the previous 3 parts in this series:
Part 1
Part 2
Part 3


1). The Essential Oils Revolution (May 13, 2015) [Video] Robert Pappas discusses essential oil adulteration. Retrieved from

2). Alexis St-Gelais (March 17, 2016) Quality Control 101. III. Is Carbon 14 Testing a Reliable Method to Detect Adulteration? Phytochemia Blog. Retrieved from

3). Essential Oil University. (2016) Explanation of trace marker peaks with example. Retrieved from

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