CPTG: Why it is Important, and How it is Determined

Welcome back to Harvesters’ Corner! We recently passed the Spring Equinox here in the Northern Hemisphere, and it is so wonderful to see the trees budding out, and I have been enjoying the wonderful scent from the Texas Mountain Laurels blooming in my neighborhood. Today we are doing to peel the curtain back a bit where the science of the oils is concerned and take a look at the various types of tests ran on an oil to determine its purity. For those of you who have been reading our past articles, you have seen the term “CPTG,” or Certified Pure Tested Grade make several appearances, especially where oils that can be used in food preparation are concerned. There are many critics online who troll a product labeled as such, saying that it is simply a marketing term used to make a product sound better than another. CPTG is much more, however, especially when the purity of a product can affect its interaction with our bodies. Let’s take a look at what is needed for an oil to receive the Certified Pure Tested Grade designation.

Essential oil freshly distilled

In our first science blog we addressed the terms purity and adulteration. As a quick recap, purity is used to identify a substance that is free from adulteration, and we defined adulteration as the action of making something poorer in quality by the addition of another substance. The idea of quality was also addressed and was indicated as the process where a substance is measured against an item of the same kind. Quality control involves checking a product’s standards throughout the manufacturing process.

The Process

Where an essential oil is concerned, how is the quality determined? What is the system used to check quality control through the cycle of growing, distillation, and bottling, and when is an oil tested? As indicated previously an oil’s quality is measured against prior testing. Every product, be it a vehicle, plane, medicine, food product, or oil, has a baseline evaluation which provides the standard by which the products are compared to. Even something as simple as water has a standard for its quality to be checked against.

For essential oils, a standard is relatively easy to obtain. We go to the source for the oil. Depending on where the oil originates, samples may be taken from multiple locations to reduce any variability that may arise during the testing. This helps scientists to be able to identify if adulterants have been added in attempt to make something better, or if  pesticides were used on the plants as they grew. All future batches of the product are compared to the standard once it is established.

Now let us turn our attention to the following questions. When is the oil tested? Who does the testing? What tests are run to assess the purity? For an oil to receive the Certified Pure Tested Grade designation, a sample of the oil is tested prior to being accepted from the grower. Once the purity of the sample has been assessed and the oil shipped, it is again tested upon arrival at the bottling plant. Multiple samples are taken and tested again, to ensure the product received matches the sample sent earlier. Random samples are also tested during the bottling process before the batch enters the inventory for shipment to people who have purchased the oil. As I am hoping you are starting to see, the organization testing the product is a critical component in this process. If a company is doing all of the testing in-house, how can consumers have confidence in the results?

The A.R.P.C.

This is why the majority of testing being done on oils produced for doTERRA is handled by the Aromatic Plant Research Center (APRC), based in Lehi, Utah, U.S.A. This independent facility provides natural product research, testing, and analysis services for companies world-wide. The battery of tests they conduct examine samples for evidence of pesticides, allergens, physical constants, fragrance analysis, and presence of carrier oils. Let’s take a look at the process where lemon oil is concerned.

Lemon oil is one of, if not the, best-selling oils in the world. A single tree produces between 500 to 600 pounds (227 – 272 kg) of lemons annually. It takes roughly seven pounds (3.2 kg) of lemon peel to fill a 15mL bottle of oil. The product used by doTERRA comes from Italy and Brazil. For our present purpose, we are going to focus on the producer in Italy. The Amadeo family has a long, rich history with lemon oil, with the present CEO, Salvatore, being the fourth generation of the family raising lemons for use in essential oils. His brother, Roberto, is the company’s Quality Control officer, and as such, is well-acquainted with the standards doTERRA is looking for in its products. He frequently pulls fruit from the orchard to run his own series of tests to ensure there are no surprises at harvest time. Several of the tests he runs are of a tactile nature, utilizing his senses. He smells the oil, tastes the oil, and rubs it between his fingers to check it. Then he runs the oil through a Gas Chromatography (GC) analyzer. This is a sophisticated piece of equipment that vaporizes the sample and assesses the levels of the molecules found within. The process requires about an hour for the test to complete, and its results are mapped out on a computer for Roberto to evaluate. He is then able to advise his brother on how the crop is maturing, and if there are any problems developing that need to be addressed.

Then harvest time comes. The fruit is gathered and separated from the peel, with the latter undergoing a steam distillation process to obtain the oil. As the process is underway, random samples are gathered and sent to doTERRA, who forwards them to the Aromatic Plant Research Center. The ARPC undertakes some of the same tests Roberto did back in Italy. How does the oil smell, look, and taste? They also assess the oil’s Specific Gravity, which means they compare the oil to pure water, and see if the results are comparable to prior batches of Lemon oil they have tested. They also assess the Refractive Index, assessing a beam of light passing through the sample. Does the light respond as it has in prior batches?

Testing Time

Don’t worry if you have test anxiety here. The only need for concern is if an oil has been adulterated.  The sample is then run through a battery of tests including a dual Gas Chromatography/Mass Spectrometry (GC-MS), a Chiral GC-MS, and a Gas Chromatography Flame Ionization Detection (GC-FID) device. Lastly, the ARPC runs a Liquid Chromatography/Mass Spectrometry (LC-MS) test. Whew! Why so many, and what does each do? Let’s find out.

In prior blogs we have mentioned the various components found within the oils. In our last article we looked at Spikenard and discovered that close to ninety percent of the elements found in the oil are in miniscule levels. The GC-MS is what enables scientists to determine what the components are, and if they are present in an accepted range. The evidence of a molecule coming back too high out of range, for example, may indicate adulteration by adding a chemically synthesized component to the oil. On the other side of the spectrum, the absence of minor components may indicate a synthesized oil, rather than a natural oil. This is why the GC-MS test is one of the standards run world-wide.

The ARPC acknowledges that each test, alone, has limitations. The GC-MS can paint an accurate picture of the oil’s makeup, but it can’t detect the presence of pesticides. That is where the LC-MS test shines through. The GC-FID takes a closer look at the volatility of an oil. This helps ensure that the more volatile components aren’t overlooked by other tests being run. The Chiral GC-MS looks at the molecular formation of the molecules. Every molecule in nature has a specific shape, usually a form of a curve, based on the atoms that form it. This is comparable to a key, like a house key or a car key. If the receptors in our body don’t recognize the key, the benefits we are looking for won’t be realized. There are a handful of molecules which possess a reverse chirality to another molecule, enabling it to trigger a different type of receptor. The Chiral GC-MS assesses to ensure that the curves which are supposed to be present, indeed are.

Why is chirality important? In December of 2024 scientists were exploring the possibility of what they called mirror life. “Driven by curiosity and plausible applications, some researchers had begun work towards creating lifeforms composed entirely of mirror-like biological molecules,” indicated a report published in the journal Science, on December 12. “Such mirror organisms would constitute a radical departure from known life, and their creation warrants careful consideration.” The article continued to explain that the building blocks of life—DNA and RNA—are made of “right-handed” nucleotides, while proteins which our bodies need to function are made up of “left-handed” amino acids. Compare these nucleotides and amino acids to a baseball glove. Just as a right-handed glove won’t work on the left hand, modified molecules with their native chirality reversed would not benefit the body on the molecular level. The scientists concluded that the risks associated with further research were worrisome enough that they were recommending any such research be discontinued and not allowed in the future.  (1) Why the concern? Imagine food that can’t be digested, or bacteria and/or viruses which medication can’t combat. While chirality seems like a trivial item to have to assess for, the implications of the wrong chirality pose great concern.

Once the ARPC is through with its testing regime, they present their findings to doTERRA, and the oil is then determined to be pure or not. If the oil is pure, the shipment is purchased.

CPTG

Back to our Lemon example. Once the Amadeo family receives notification that their harvest has been purchased, it is shipped to America and sent to Utah. As indicated earlier, upon arrival at the bottling plant random samples are drawn from the containers and sent to the ARPC for re-testing. The results from the second test are scrutinized against the first test to ensure a match. Only then are the containers unsealed and allowed to enter the bottling facility. At this point, random samples can be drawn off and assessed in-house by the scientists working with doTERRA to assess that the standards continue throughout the process.

How and why the testing is important.

The end result of this example is a bottle of Certified Pure Tested Grade (CPTG) Lemon oil, which is also certified as Generally Regarded As Safe (GRAS) by

the US Food and Drug Administration. Now I can purchase this bottle and put in water I drink or use to enhance recipes needing lemon zest. I also have satisfaction knowing that due to the testing being done, the bottle of oil I receive in 2025 is as pure as the bottles I received back in 2013 and 2014.

While every oil which passes this rigorous testing can be CPTG, I would be remis to point out that not all oils are GRAS. Always check the label on the bottle to verify that the supplemental facts table is present for oils that are GRAS. If there is no table, then the oil should not be taken internally. A good rule of thumb is if the source product is commonly eaten, the oil will likely be GRAS.

This may seem like a lot of time and effort being spent to ensure purity, and it is. However, I have also seen other producers of essential oils label bottles of Lemon with warnings that state the oil is not to be used internally, and bottles of Lavender oil that warn to keep the oil away from open flame. I shudder when I consider what additives have been put in those oils to necessitate such warnings.

As I have indicated repeatedly in these articles, CPTG is more than a fancy marketing term. It is a standard I have explicit trust in, because I know the level of care and testing done to ensure these oils are truly pure.

I encourage you to look at CPTG oils and try the difference for yourself. Join us next time, here at Harvesters’ Corner, when we take a look at clove oil. Until next time, stay safe!

Sources

1.    Hunt, Katie. “Scientists warn of “unprecedented” risks of research into mirror life.” CNN, 17 December 2024. Online. < https://www.cnn.com/2024/12/16/ science/mirror-bacteria-research-risks/index.html>. Accessed 18 December 2024.