Essential oils are volatile aromatic compounds that are generated within flowers, roots, trees, shrubs, bushes, and seeds. The power of essential oils comes from the active constituents that the plant contains. The constituents of a plant are naturally occurring chemicals that give them their specific health-supporting properties. Essential oils have a unique ability to penetrate cell membranes and travel throughout the body through blood and tissue. Each essential oil is unique and contains multiple constituents. This is why some essential oils seem to have a vast range of therapeutic benefits. Each essential oil is unique so no two oils are alike. Constituents are chemistry, and if you don’t want to know all the nitty-gritty details, it can be challenging to find a simple explanation. In this post, I have tried my best to explain constituents as simply as possible. I believe it is important for anyone interested in essential oils to have a basic understanding of what constituents are. Otherwise, you will not understand why essential oils have health supporting benefits and how to use them efficiently. After I began to understand constituents, it was like a lightbulb went off for me.
Categories of Constituents:
The aromatic constituents of essential oils are usually sorted into 14 categories, and categorized based on their chemical structure. Some people like to think of these groups as chemical families. A few examples of these chemical categories are: terpenes, esters, aldehydes, ketones, and phenols. Individual constituents will fall under a specific category based upon their chemical structure NOT the specific action of the constituent. Here are some examples of that:
Terpenes: alpha-pinene, limonene
Esters: linalyl acetate, benzyl benzoate
Aldehydes: citronellol, citral
Ketones: menthone, camphor
Phenols: eugenol, thymol
One of the most common categories of constituents found in essential oils are terpenes. For example, all the constituents listed below are in the terpene family. As you can see, the therapeutic benefits of the constituents below are not all the same. This is why it is important to look at the specific constituents within the essential oil, and not the category they are in. Although each constituent below is classified as a terpene, you will notice that each constituent has different therapeutic benefits.
Linalool a calming constituent that offers us support in areas such as sleep and mental wellness. It is found in essential oils such as: clary sage, lavender, neroli, and coriander.
1,8-Cineole is a strong constituent that offers us respiratory support, as well as being warming and calming when applied to skin. It is found in essential oils such as: rosemary, cardamon, camphor, eucalyptus radiata and globulus.
Alpha-Pinene is a supportive constituent that can give relief to the body during times of occasional physical discomfort; it can also support strong emotions. It is found in essential oils such as: frankincense, pine, cypress, and nutmeg.
Limonene is a light constituent that supports our immune health and is stimulating and uplifting to our senses. It is found in essential oils such as: lemon, lime, orange, bergamot, elemi, grapefruit, and palo santo.
Geraniol is a cleansing constituent that offers skin support and is beneficial during times of seasonal illness. It is found in essential oils such as: citronella, geranium, geranium bourbon, palmarosa, and rose.
Although multiple essential oils can have some of the same constituents, the percentage of the constituents will not be the same. There will be what is referred to as key constituents within the essential oil. The key constituents are the constituents that have the highest percentage within a specific essential oil. These key constituents tell us what the therapeutic benefits of the essential oil are. Therefore, proper manufacturing is important when making essential oils. This ensures the plant’s constituents remain intact. Otherwise, the essential oil will not contain its therapeutic properties and is essentially just a liquid aroma.
If you would like to dig more into this subject, here are some resources that may be beneficial to get you started:
- Different Essential Oils- Similar Groups of Constituents (An online post)
- Functional Group Theory – Does it Work? (an online post)
- Chemistry of Essential Oils Made Simple (book)
- EOU Database (free online searching database)
- Essential Oils Home Reference (book)
- The Chemistry of Essential Oils (college level online course)