Chemistry. Already getting nervous? The chemistry chapters of essential oil texts are the most frequently skipped, even by natural health professionals. But it can be fun and useful...really! Knowing what essential oils are made of, and how this affects their aroma and therapeutic value can have a big impact on the efficacy of your aromatherapy practice. Understanding the basics can help you make better choices in essential oils, and better choices in their application. Plus, this can give you the foundation for further understanding of true "medical aromatherapy", as practiced in much of the rest of the world. So here's a primer on the chemistry of essential oils, with some common examples and important tips to help you grow as a holistic medicine practitioner.
So, why are essential oils called "oils" anyway? They don't feel greasy, and they tend to evaporate completely, unlike common "fixed" oils (such as olive, grapeseed, hazelnut and the like). Essential oils and fixed oils share a similar chemical foundation: their structures are based on the linking of carbon and hydrogen atoms in various configurations. But this is really where the similarity ends. Fixed oils are made up of molecules comprised of three long chains of carbon atoms bound together at one end, called a triglyceride. Every fixed oil is made up of just a few different triglyceride arrangements - olive oil, for example, is primarily made up of oleic, linoleic and linolenic acids (the names of particular carbon-hydrogen chains forming the triglycerides). Their long-chain shape holds them in a liquid state which does not easily evaporate.
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 (here, many folks might be responding with "Say what?!?"). An essential oil is actually made up of many liquid chemicals; sometimes more than one hundred distinct chemicals are found in one pure essential oil. Each of these 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.
Many factors in an essential oil's production affect the total number and relative amounts of individual chemicals found in the final product. These include where the plant was grown, soil and climate conditions, time of harvest, distillation equipment, plus the time, temperature and pressure of distillation. This can give you an idea as to why two varieties of the same oil can smell so different: The full, beautiful bouquet of a fine essential oil will contain a myriad of notes, telling you that all natural components are present and in balanced amounts. Poorly distilled oils may lose some of the secondary constituents during production, and adulterated or synthetic oils may not have some of the trace components at all, detectable by your nose as a flat or uninteresting aroma.
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.
So how is this synergy reflected in Lavender's aroma? Each of these chemicals has a unique smell; some are sweet, some are camphorous, some citrusy and some herbaceous. It is all these chemicals together, a precise amount of each, that gives each lavender variety its distinct aroma. And your nose knows this! One can tell the difference between a well-made, complex lavender oil with many notes within the aroma, and one that is flat or plain, which may be chemically imbalanced or missing some trace constituents. Start trusting yourself here - a great oil is not made by marketing, and your olfactory scent is the best tool you have to guide you to the most therapeutic Lavender for your needs.
All essential oils are subject to similar variations in production methods or the manipulation of their molecular make-ups through the addition of synthetic chemicals. 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, not just their bottom line. 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. With even more education and skill, you'll start to recognize individual chemicals within an oils aroma, and make the best decisions as to which oils will have the most profound therapeutic affects for you, your family, or in your professional practice.
Author Resource:
The author has made available much information about aromatherapy, such as using lavender and other highly regarded essential oils .