The different molecules found in essential oils give them their unique aroma and properties. Their chemical makeup affects how you and the oil interact.
Each essential oil also has a different number of molecules. Grapefruit, for example, is almost entirely made up of one kind of molecule, limonene, whilst Patchouli, has a diverse number of different molecules.
Essential oils are complex, particularly those containing hundreds of molecules. Too much or too little of any given molecule, affects the aroma and therapeutic properties of the essential oil.
Since molecules are atoms linked together through a chemical bond connecting different types of atoms, they can be both a molecule and a compound.
For instance water is made up of hydrogen and oxygen, and is therefore both, a compound and a molecule; however, ozone, which has three oxygen atoms joined together, is only a molecule.
Essential oils are filled with different kinds of compounds that are all volatile. Volatile meaning a substance that can change quickly from a liquid to a gas.
No two plants will produce essential oils with the same chemistry, even those from the same species. Variations in their chemical composition are determined not only by the chemical makeup of an essential oil, but are also affected by the region in which it was grown in, the time and season in which it was harvested, and the soil quality in which the plant was grown. For example, lavender grown in Bulgaria will have a different chemical composition from lavender grown in the Himalayas.
In the same species, however, the main difference between two plants can be the amount or percentage of the major compounds for that species. Lavender from the Himalayas and lavender from Bulgaria will both have the compounds linalool and linalyl acetate, but in differing amounts. This can be a defining characteristic because the chemical profile of any oil affects the benefits it produces.
At times, the environment in which the plant is grown can significantly impact its chemical composition. Two plants can have the same genus and species, look and grow alike, but diverge within the species into different chemotypes, due to their vastly different internal chemistry.
To Be or Not To Be Pure, That is the Question
Producing high-quality, pure essential oils can be expensive, so some suppliers reduce costs by diluting the product with other substances. Some dilutents are more harmful than other and can range from vegetable or synthetic oil, to artificial chemicals or disguised using less expensive oils to bulk out the expensive oil.
For example, using cassia instead of the more expensive cinnamon, or spike lavender instead of lavender. Lemongrass oil is widely produced, less costly, and similar to melissa oil, which is one of the rarest and most precious essential oils. To the untrained eye, or nose, lemongrass oil could be falsely represented as melissa oil and sold at a larger price.
Companies may not be aware that the oils they produce are adulterated. Often, they buy from brokers they trust, who may have cut corners with fillers, and then advertise their product as 100% pure. Unfortunately legislation around the essential oil industry is neither rigorous nor adequate. Only 5% of the liquid in the bottle has to be pure essential oil or organic for it to be labelled as such.
Expertise and adequate quality testing are expensive and not an industry standard, however with the right resources, even the most sophisticated kinds of adulteration can be detected.
Common Forms of Adulteration
One of the most difficult adulteration methods to detect is the addition of natural, isolated volatile organic compounds. Natural isolates are chemical compounds present in other plants which are isolated and removed from their natural source and then added to an oil. For example, linalool from an inexpensive oil like ho wood could be isolated and added to an expensive oil such as rosewood.
Another example is turpentine, a byproduct of the paper-making industry and a natural source of alpha-pinene from trees. Alpha-pinene can be easily extracted from turpentine in pine wood and added to an essential oil naturally containing alpha-pinene, like frankincense. However, frankincense is 45–50 times more expensive than alpha-pinene isolated from turpentine.
Producers may also mix less expensive oils with others to cut costs, ie the addition of lavandin to lavender essential oil, or mixing clove stem essential oil with clove bud essential oil. Or a less expensive oil may have been substituted altogether, like disguising cassia oil as cinnamon oil.
To detect adulteration of natural isolates, the presence or absence of naturally occurring volatile molecules and incorrect molecular ratios must be carefully studied.
In some cases, essential oils are diluted with a carrier oil to avoid skin sensitivity. It’s a common practice and not considered adulteration if the contents of the bottle are stated on the label. This process becomes adulteration when a carrier oil is added to an essential oil and not listed on the contents of the bottle.
For instance, castor oil can be added to frankincense or patchouli in small quantities, so it is cheaper to produce. Instead of pure frankincense oil, considerable amounts of carrier oil are added to look like pure frankincense as a lower-cost alternative.
The addition of synthetic chemicals is potentially very harmful. Some naturally occurring volatile compounds are easily synthesised in a lab. Carvone (found in spearmint) and carvacrol (from oregano) can be synthesised from limonene. These synthetic chemicals are cheaper than the natural isolate and may be added to an essential oil to raise profit margins.
Synthetic chemicals similar to their natural equivalents are easily made from common petroleum products. There are millions of tons of cast-off byproducts from the petroleum industry, where the raw material phenols and other components from gas and oil can be changed into nearly any chemical constituent through simple chemical processes.
Lavender
Lavender is also commonly adulterated with synthetic chemicals. This is because linalyl acetate naturally occurs in lavender in large quantities, and synthetic linalyl acetate is an easy compound to create. Turning a small amount of real lavender oil into a large amount of adulterated oil is easily done by adding the synthetic compound.
Oils like neroli and ylang ylang may be completely reconstructed with synthetic chemicals and be unnoticed by an untrained chemist, making them not at all safe for topical or internal use and personally I wouldn’t defuse them either. The commonly used oils are the most abused oils, eg Lavender, Frankincense, Peppermint and Tea Tree. In this instance the price really does reflect the quality. This is why I only use DoTERRA oils, which are traceable from grower to bottle and every process along the way, with rigorous testing and ethical practises. They are not the only company that sell legitimately pure oils, but they are of a very select few.
If you would like to know more, I’m happy to help.
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