Beginning Essential Oil Chemistry
Chemistry?!? Are your eyes glazed over yet? It happens…yet if you’re interested at all in the therapeutic use of essential oils, a little primer on their chemistry can be very useful. Not only will you better understand how and why essential oils work, but the great importance of using natural, high-quality oils - oils that are pure, properly distilled, AND smell nice - will be made clear. It’s not just an aromatherapy sales pitch; essential oils with exceptional bouquets have different chemical make-ups than flat or otherwise uninteresting oils. The differences can significantly affect the healing potency of therapeutic applications for you, your family and/or your clients. Much of the time, you can discern the difference of therapeutic value between two oils just by their aroma - one needn’t always have the proof of fancy, expensive machines to make an educated choice.
So what is it that makes an essential oil different than every other oil we’re familiar with? They don’t feel the same, they don’t act the same, and they certainly don’t smell the same. Essential oils and the so-called “fixed” oils (you may also know them as carrier or base oils - like Sweet Almond, Apricot Kernel, Evening Primrose, etc) are distinctly different in their molecular structure. While both essential and fixed oils share common basic atomic elements of Carbon and Hydrogen, that’s really where the similarity ends. Fixed oils are made of triglyceride structures - three long chains of carbon atoms, with hydrogens bonded at various places. The length of the chains and the position and number of hydrogens define the nature of the oil; if hydrogens are bonded to every available location, the oil is “saturated’, for example. One missing hydrogen is “mono-unsaturated’, more than one is “poly-unsaturated’. The long chains and relative consistency of the molecular structures makes fixed oils “oily’, and does not allow them to evaporate quickly.
Volatile oils are another matter - volatile oils do easily evaporate, due in-part to their smaller, more complex structures. Essential oils are a sub-category of volatile oils, essential oils being specifically those volatile oils that have been distilled directly from plants (rather than laboratory made, or from another otherwise “inorganic” source). Essential oils still have a core structure of linked carbon and hydrogen atoms, but they come in a great variety of shapes including short chains, rings and multiple-rings hooked together. Each of these core structures will have what is known as a “functional group” attached - a sort of “molecular sub-unit”. Despite their seeming complexity, though, essential oils are still very compatible with mammalian biology - their atomic structure allows them to penetrate into the deepest regions of our bodies, and even to the centers of our cells.
The therapeutic action of an essential oil is primarily determined by the “functional groups” found in the molecules that make up that oil. An essential oil is actually made up of many individual molecular constituents. Each of these natural chemicals is formed of a carbon-hydrogen structure with a functional group attached. It is the combination of the base structure AND the attached functional group that makes a single, unique molecule. And MANY of these unique molecules combine to form ONE essential oil.
The extremely complex nature of essential oils becomes apparent from this description. There are an almost infinite number of molecular combinations that can be formed from the building blocks of chains, rings and functional groups. And any SINGLE essential oil is made of many, sometimes even hundreds of these molecular combinations. Yet while this may sound complex, you needn’t know ALL the chemical details to use oils therapeutically. It IS helpful to know that each oil is made of many molecular forms, that all the molecules within each oil exert some biologic effect, and that it is the SYNERGY of ALL these molecules together that create the sum total of an oil’s therapeutic action AND its aroma. Nearly every laboratory study comparing complete, pure essential oils to one singled-out molecule that was thought the “active ingredient” shows the essential oil to be more active.
The essential oil with the most perfect balance of natural chemical constituents will have the finest aromas and the most potent therapeutic action. Many factors in an essential oil’s production affect this balance. These include where the plant was grown, soil and climate conditions, time of harvest, distillation equipment, as well as the equipment settings and skill of the distiller. This can give you an idea as to why two varieties of the same oil can smell so different: The wonderful aroma of a fine essential oil will contain an array of notes in a lovely balance, telling you that all natural components are present in the correct amounts.
To best understand this, we’ll examine Lavender essential oil; more than fifty individual molecules have been identified in pure lavender essential oil. The aromatherapist must remember that ALL of these chemicals found in pure and natural lavender oil work together to produce a therapeutic effect. For example, the linalool molecule is antiviral and antibacterial; the linalyl acetate is emotionally calming; other major components including cineol, limonene, pinene and others are all noted for specific biologic and aromatic activity. It is the combined, balanced, synergistic action of these chemicals that make pure, high-quality lavender such a great healer. No one chemical can be singled out and used to give the same profound results as the complete pure essential oil.
What does this mean to the lay-practitioner? That it’s important to find a nice smelling lavender oil! Each of the individual chemicals has a distinct smell, talked about in terms of “notes” within the overall lavender aroma. A precise amount of each will create a certain Lavender aroma. Some Lavenders are more sweet (and therefore more relaxing), others are more herbaceous (and more anti-microbial). There can be significantly different aromas from the same species of plant, even when the essential oils are of the highest quality. It is most often the essential oil that smells the most “true” to you that will be the most beneficial. Your senses can naturally detect what is good for you and what is not, if you’re willing to listen to them impartially.
For the most therapeutic benefit, it is always best to use true, carefully-made essential oils. To do this, find a source that is dedicated to supplying only the highest grades of oils. Examine their product’s aromatic quality and business practices and so that you are comfortable with their dedication to your health. Listen to your intuition and your own nose; they won’t lie to you! With experience, your ability to discern between subtly different grades of oils will become more astute. And you’ll understand what it is about the oil, chemically, that makes it unique.
For more on the wonderful therapeutic potential of aromatherapy and essential oils, visit The Ananda Apothecary of Boulder, Colorado.