Essential Oil Adulteration. Common or Uncommon Practice?

In July of 2019,, a site dedicated to reviewing products and services across a wide and complex variety of categories, worked with an independent lab to test essential oils from well-known names in the essential oil industry

Main Focus of the Study


The main focus of the study was to discover if essential oils from well-known brands have been adulterated, meaning if any extra substance, typically synthetic, was added to the essential oil during its production. Companies are allowed to make any claims they want, but what's really in the bottle consumers can't know without the proper testing.

The Essential Oils

Lavender, peppermint and tea tree (Melaleuca) samples of each brand were sent to the laboratory. In the end, the adulteration report only focused on lavender and peppermint because...

"...proving adulteration in tea tree oil is more difficult than in lavender or peppermint because of the chemical composition... and unless we are certain, we are not going to say it’s adulterated. A lot of those tea trees we had a good reason to suspect something had been played with, but unless we were really certain, we didn’t want to say it was. Unless we had proof, we didn’t want to speculate,” said the laboratory.

What are essential oils?

The Brands

Essential oils were purchased from 11 well-known brands and sent unlabeled to Aromatic Plant Research Center (APRC), an internationally renowned independent laboratory, to conduct a GC-MS test on the oils.

What about testing for overall quality, safety & potency?

Many other tests would be needed to test for overall quality, safety & potency. This study only focused on finding out whether adulteration could be detected using a GC-MS test.

An essential oil may be adulteration free, still lack the proper potency to be effective or the purity to be safe. Season, year, climate, location, as well as its extraction process, storage, etc. all play a role.

Sustainable Sourcing

In addition, Consumer Advocates provided general information about how each brand educates their customers and sources its oils. Sustainable sourcing is very important as the use of essential oils becomes more widespread, the environmental impact of essential oils is another crucial factor worth taking into account.

A large number of plants used to produce essential oils are considered endangered, while others are increasingly overharvested. Some names in the industry have been found guilty of illegally trafficking essential oil ingredients, and practicing unethical behavior in sourcing their oils.

Company initiatives that ensure living wages and community benefits for small-scale farmers and their families is also of ethical concern.

Read the entire article here.

What is GC-MS testing?

Gas Chromatography with Mass Spectrometry (GC-MS) is the workhorse of APRC. GC-MS is a testing method that separates the volatile compounds in essential oils into individual components and identifies each of these components and their percentages. To begin the testing process, the essential oil sample is prepared and injected into the gas chromatograph portion of the unit. Using steadily increasing heat, this machine volatizes the sample, causing the molecules to separate based on their size and nature of the molecule. The lighter components travel faster and are the first to leave the GC column. These separated molecules then enter the mass spectrometer where they are fragmented. The molecules are separated and organized by their mass and the time it took to travel through the GC column.

This information is used to determine the percent and variety of chemical constituents included in the essential oil being tested. GC-MS testing allows APRC to identify the type of essential oil being tested, determine the purity and composition of that oil, identify the chemical profile, and recognize and distinguish any potential contaminants. It is one of the key steps in the rigorous and sophisticated testing process that APRC uses to identify the chemical profile of an essential oil.

Results of the Study

- Adulteration is common practice in the essential oil industry
- 8 out of the 11 brands were found to have adulteration

The Consumer Advocates team spent over 600 hours of research, analyzed 33 essential oil samples; and collaborated with a group of experts who have dedicated their careers to researching and writing about essential oils.

In the end, only adulteration in lavender and peppermint samples were reported in the study, even though a lot of the tea tree oils had a good reason to suspect they'd been played with. The laboratory decided to do this because they didn't want to claim an oil was adulterated unless they could be absolutely certain, because of the difficulty in proving adulteration in tea tree oil with GC-MS testing.

By brand name, in alphabetical order:

  1. Améo - None detected
  2. Aromatics International - None detected
  3. Artisan Aromatics - Adulteration markers detected in lavender oil
  4. Aura Cacia - Synthetic markers detected in lavender oil
  5. doTERRANone detected
  6. Edens GardenAdulteration markers detected in lavender oil
  7. Mountain Rose Herbs -  Adulteration detected in peppermint oil from the addition of menthol, menthyl acetate, and Himalayan Cedarwood
  8. NOW - Adulteration detected in peppermint oil from the addition of menthol, menthyl acetate. Adulteration detected in lavender from synthetic markers of linalyl acetate.
  9. Plant TherapyAdulteration detected in peppermint oil from the addition of menthol, menthyl acetate. Adulteration detected in lavender from synthetic markers of linalyl acetate.
  10. Rocky Mountain OilsAdulteration detected in peppermint oil from the addition of menthol, menthyl acetate.
  11. Young Living - Adulteration was detected in Young Living oils. Young Living then threatened Consumers Advocate with a lawsuit. Consumers Advocate removed the results from the study for the time being while the issues is being contended.


Essential oils are sourced from all over the world, and as a consumer, you won’t have access to the inner workings of the farmer-supplier relationship.

Many companies talk about the "purity" of their essential oils. But what exactly does that mean? Similar to quality standards, there is no official entity or authority that oversees or regulates essential oil purity. That means that even oils that are labeled as 100% pure might be adulterated and can be harmful to our health.

Furthermore, there are no quality control standards for essential oils in the United States, so it’s vital that companies provide online quality and testing reports

What can companies do to prevent adulteration?

“Be involved with the farmer, have someone representing the company during distillation and during the collection and take the oils straight from them,” said the laboratory.

Read the entire article here

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