Dr. Sarah A LoBisco, ND

Last week I was discussing with an esteemed colleague how I implement the safe use of essential oils with my patients. A question that emerged in our conversation was if there was a direct comparison of the potency of essential oils to supplements or herbs that contain them. I couldn’t answer that question simply, as there are many variables that relate to essential oil strength. In this article, I will dive into the literature to explain these factors and other essential oil complexities. First, let’s start from the beginning.

What Are Essential Oils?

Essential oils should not be confused with essential fatty acids, alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid) which are found in foods. Rather, essential oils are the aromatic and volatile compounds found within shrubs, flowers, trees, roots, bushes, resins, and seeds. They are considered secondary metabolites of the plant, meaning they are not essential for life, but vital for survival of the plant. This is because they play an important role in the plant’s defense and overall immune health.1-9

Secondary metabolites can be classified on the basis of chemical structure composition (i.e. containing nitrogen or not), their solubility in various solvents, or the pathway by which they are synthesized (e.g., phenylpropanoid, which produces tannins).8 Essential oil constituents have various means of classifications. One way is to classify them is as either terpenoids or phenylpropanoids, or alternatively, into hydrocarbons and oxygenated compounds.5

According to a 2015 study,6 another way to categorize active compounds in essential oils is to divide them into four groups based on their chemical structures. These groups include terpenes, terpenoids, phenylpropenes (a subfamily of phenylpropanoids), and different degradation products originating from unsaturated fatty acids, lactones, terpenes, glycosides, and compounds that contain either sulfur or nitrogen” contained in various essential oils6

The Complexity Factor

As you can see, there is complexity to essential oils. Essential oils contain a wide array of constituents, regardless of how they are classified. These all have synergistic or differing therapeutic actions and mechanisms, which can support and balance out one’s biochemistry. Furthermore, one constituent can have multiple actions. For example, alcohols can be antimicrobial, antiseptic, tonifying, balancing, spasmolytic, anesthetic, and anti-inflammatory.5

Their chemical composition can also vary depending on the season of harvest and methods of extraction (distillation, hydrodistillation, super critical carbon dioxide extraction, and solvent extraction- the latter two are not technically essential oils). A final intricacy of an essential oil’s action to consider is its chemotype or distinct plant population within the same species. These various populations produce differing plant secondary metabolites that have differing effects.5,6,8,10

With all the potential healing properties of so many components, it’s no wonder essential oils are coming into vogue.7 It was estimated in 2004 that there were 3000 kinds of essential oils identified and 300 were commercially used in the flavor and fragrance market.6

The Power of Essential Oils On Bugs

I’ve already written on the power of essential oils for modulating antibiotic resistance and inhibiting unwanted microbes in humans. Furthermore, several recent studies have demonstrated some in vitro and in vivo evidence that essential oils may preserve our beneficial microbiota while eliminating detrimental organisms.11-13 This is wonderful news considering the importance of our microbiome for health.

The food and cosmetic industries have taken advantage of the safety of essential oils over chemicals for antimicrobial and food preservation applications.2,14-15 One study comparing the antimicrobial effects of essential oils to methylparaben in cosmetics concluded that essential oils could be used to replace this chemical at appropriate dosages:

Depending on tested microorganism strain, all tested extracts and essential oils show antimicrobial activity 0.8-1.7 and 1-3.5 times stronger than methylparaben, respectively. This shows that tested extracts and essential oils could replace use of methylparaben, at the same time giving a guarantee of microbiological purity of the cosmetic under its use and storage.15

Essential oils have many other applications which can be found on my essential oils database.

Essential Oils Straight, In Herbs, or Pills?

One study sought to obtain the potential availability of essential oils in certain herbal preparations. The study compared the essential oil yield determined by distillation from unprocessed raw materials to herbal tea bags and dietary supplements. The researchers obtained leaves of peppermint (Mentha piperita L), leaves of lemon balm (Melissa officinalis L.), and inflorescence of chamomile from retail shops in Poland. The herbal tea bags and dietary supplements (in capsules, liquids, and powders) were also purchased from suppliers in this area. The results reported in the abstract read:

It was found that the average potential availability of essential oils in the products such as dietary supplements for the doses recommended by the producers is lower than in the corresponding tea infusions: for peppermint formulations approximately 6-fold lower, for the formulations with lemon balm about 4-fold lower, and for the chamomile preparations about 3-fold lower. It was found that essential oils extracted from herbal teas have a similar chemical profile with characteristic deviations in the amount of individual components, which arise from the origin of the raw material.

This study further verified that chemotypes produced differing dominance of constituents and that supplements were the least potent for several reasons. The authors stated:

The various forms of dietary supplements such as tablets, capsules, extracts, are all very convenient for the consumer and at the same time they resemble medical potions, which may increase their perceived effectiveness in contrast to food products in the form of traditionally brewed tea bags [29]. In spite of the detailed information provided on the label or the attached description concerning the content of the herbal component, the consumers may still have problems with the correct interpretation of the potential availability of a biologically active component when confronted by other products such as herbal teas [30–32]. Dietary supplements, in spite of their significantly higher prices compared to such food products as herbal teas, enjoy a high demand among the consumers and the market for such products is constantly growing [33]. However, it is important to raise the awareness of the consumers so that they can make conscious and informed choices taking into account not only the attributes related to the simple usage of the products, but also considering the notably more important factor which undoubtedly is the potential availability of active substances present in a given product.16

Many doctors may be aware that the oil of peppermint has the most research regarding efficacy for bowel issues and irritable bowel syndrome, versus the tea or herb.17-18

Other Factors with Potency

As mentioned above, it has been shown that extraction processes and quality of raw material will effect the essential oil potency in the plant.19-21 Furthermore, temperature, storage,22-24 and synergistic effect25-28will also determine the strength of an essential oil verses the herb. Unfortunately, standardization and regulations are not specific for essential oils and cannot remediate these issues.29-36

This is why it is important to know your supplier and ask questions regarding testing for contaminants, source of raw materials, the determination of therapeutic constituents, and third party testing verification.5

Bottom Line

Quality essential oils are more potent than herbs and supplements, due to the manufacturing and availability. If you want all the benefits of the essential oil, it’s important to choose a supplier who produces quality essential oils in their whole distilled form.

LoBisco041lowresSarah Lobisco, ND, is a graduate of the University of Bridgeport’s College of Naturopathic Medicine (UBCNM). She is licensed in Vermont as a naturopathic doctor and holds a Bachelor of Psychology from State University of New York at Geneseo. Dr. LoBisco is a speaker on integrative health, has several publications, and is a certification candidate in functional medicine. Dr. LoBisco currently incorporates her training as a naturopathic doctor and functional medicine practitioner through writing, researching, private practice, and through her independent contracting work for companies regarding supplements, nutraceuticals, essential oils, and medical foods. She has a small, private wellness consultation practice through telephone and Skype. Dr. LoBisco also enjoys continuing to educate and empower her readers through her blogs and social media.


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  36. The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) is unique in bringing together the regulatory authorities and pharmaceutical industry to discuss scientific and technical aspects of drug registration
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