About Cinnamon Essential Oil
Cinnamon essential oil (Cinnamomum verum) can be produced from both the bark and the leaf of the plant. These two oils cannot be used interchangeably because they have differing chemical compositions. Cinnamon bark oil contains up to 60-75% of a chemical known as cinnamaldehyde, while cinnamon leaf oil contains up to 95% of a substance called eugenol. While the oils come from the same plant, the two oils are extremely different. As a result, the studies outlined below specify which oil was used.
NOTE: Cinnamon bark oil is often adulterated with cinnamon leaf oil and cassia oil, so it is always a good idea to confirm oil quality before considering using an oil in aromatic medicine.
Actions & Indications
As an herbal ingredient, cinnamon is a popular culinary spice. It is used in herbal medicine to reduce insulin resistance and improve oral health. Both of these applications are supported by the scientific literature. Its effects on oral health are attributed to its powerful antimicrobial actions and its impact on insulin resistance is attributed to its documented ability to improve glucose metabolism. Its uses in aromatic medicine are similar, but it should be noted that its effects differ; herbal medicine and aromatic medicine cannot be used interchangeably.
The essential oil has been shown to act as a powerful antibiotic in laboratory studies, with potential to play a vital role in prolonging the antibiotic era. It has also shown to have beneficial effects when used as an ingredient in oral care products and as a potential preventive for type 2 diabetes.
Laboratory Research Studies
Chemopreventive: Cassia oil, a cinnamaldehyde-rich relative of cinnamon oil may have cancer prevention actions, according to a 2011 study which evaluated the effects of the oil on colon cancer cells. This study established the potential for the oil to exhibit preventative actions. The researchers found that the oil activates a natural, antioxidant-related response that inhibits cancer cells, specifically in this case, colon cancer cells.
The study was a laboratory study, not an in vivo study, so additional research is needed to determine how these findings can be applied to human health. However, the potential for additional findings that relate to oils in the cinnamon family may support the addition of these oils to the diet as a preventive measure.
Antibacterial: In multi-oil studies, cinnamon (bark) essential oil consistently demonstrates efficacy against MRSA and similar microbes responsible for bacterial skin infections. In vitro studies also indicate that cinnamon essential oil works synergistically with pharmaceutical antibiotics in order to boost efficacy against gram negative strains of bacteria. These findings could help prevent the need for second- and third-generation antibiotics, helping to prevent antibiotic resistance.
Gut Bacteria: However, a 2016 study confirms that cinnamon (bark) essential oil does eliminate lactic acid bacteria, which are beneficial probiotics. These findings indicate that ingestion of the oil has the potential to harm gut health, which is to be expected given its indication as an antibiotic. Therefore, while it is and can be quite beneficial for its indicated uses, care should be taken when ingesting cinnamon essential oil in medicinal doses, just as one would with conventional antibiotics.
Animal Research Studies
Glucose Metabolism: As insulin resistance is a rapidly growing concern, there is increasing interest in identifying natural solutions. Cinnamon and cinnamon oil have shown promising results, but these studies need to be evaluated accurately with appropriate uses delineated. Many essential oil websites have an abundance of claims about the use of cinnamon oil as a cure for diabetes, but that cannot be supported by the literature. What can be supported by the literature is clearly demonstrated in a 2004 study. In this study, essential oil blends were administered to rats with obesity and type 2 diabetes. The study found that glucose tolerance was improved at the end of 4 weeks of supplementation.
These results indicate that obese individuals at risk of developing type 2 diabetes may benefit from supplementation with cinnamon oil as a preventive measure, and that cinnamon oil may have insulin-like action while affecting insulin signaling. This means that the oil can play a role in prevention but is not suitable as a stand-alone treatment after the onset of diabetes. It should not be used in place of prescribed treatments, but with oversight from a licensed care provider could be added liberally to the diet as part of a holistic approach to reducing the lifestyle factors that are linked to the development of type 2 diabetes.
Cinnamon Essential Oil Safety
- The leaf oil is also said to have tumor-promoting abilities in rats, though documentation is unclear.
- Ingestion of the oil may deplete glutathione, an important element of the natural detoxification process.
- As cinnamon oil may exhibit insulin-like activity, ingestion of medicinal amounts has potential to interact with insulin treatments or other drugs that affect blood sugar levels.
- Those with sensitive skin should avoid undiluted or high dilutions of topical applications because the oil is a documented irritant.
Essential oil ingestion (aka aromatic medicine) is not recommended for children younger than the age of 7, those who are pregnant or may become pregnant, those who are breastfeeding, and those with underlying health conditions without advanced training or consultation with someone trained specifically in the science of essential oil ingestion.
Topical Application: Cinnamon essential oil can be used in skincare at dilutions up to 0.5%. In medicinal applications such as a balm, up to 1-2 drops diluted to 2% to 10% of the total product are suitable for an otherwise healthy adult on an as-needed basis. Total concentration of the oil, frequency of application, and duration of treatment is dependent on the other ingredients in the formulation and the condition being treated.
Like most commercial antibacterial agents, the oil can cause stinging, burning, redness, and irritation, particularly when applied to damaged or infected skin. Maintaining proper dilutions will help to reduce, but not eliminate this side effect. Individuals with sensitive skin may prefer to avoid cinnamon oil and rely instead on a non-irritating agent to treat topical infections. While popular articles on social media advocate reducing the total cinnamon oil content to avoid irritation, reducing the total concentration also reduces and potentially eliminates the oil’s efficacy. Achieving the proper dose is a requirement to achieving efficacy. Such applications require consultation with a professional who is trained in formulation.
Ingestion: 6-8 drops per day is the upper limit for an otherwise healthy adult. See notes on aromatic medicine.
Cinnamon EO LD50: (oral) bark: 3.4g/kg (rat) and leaf: 2.7g/kg (rat)
Tips & Notes
Cooking with Cinnamon EO: Cinnamon is frequently used in after dinner mints and other candies. Because it is an irritant, it should be added as less than 0.05% of the total recipe. It also works well in baked goods and other products that have an abundance of fatty acids that dilute the potency of the oil.
Methods of Administration: Cinnamon essential oil can be used in extremely small amounts for skincare products, particularly wash-off products such as a body scrub. For medicinal purposes, it can be added to a balm for wound care or first aid. Cinnamon oil is a dermal and mucus membrane irritant, so it should always be diluted in a lipid or other acceptable substance to protect the body.
Notes: In the late 1980s and 1990s, cinnamon oil was abused by adolescents. Reports indicate that the most significant toxicological concerns include irritation to the mucus membranes and allergic reactions. One collection of data reported within a five month period in Pittsburgh documented 32 cases of cinnamon oil being consumed from a toothpick or finger dipped in the oil. This would equate to the direct ingestion of 1-2 drops total. The reported effects included oral burning, flushing, nausea, and abdominal pain. Because cinnamon oil has such documented effects, attention should be given to the proper dilution of the oil prior to consumption in any form of culinary preparation or aromatic medicine.
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Perry, PA., Dean, BS., & Krenzelok, EP., (1990). Cinnamon oil abuse by adolescents. Human Toxicology. 32(2): 162-4
Talpur, N., Echard, B., Ingram, C., Bagchi, D., & Preuss, H., (2004). Effects of a novel formulation of essential oils on glucose-insulin metabolism in diabetic and hypertensive rats: a pilot study. Diabetes, Obesity, and Metabolism. 7:193-199.
Valcourt, C., Saulnier, P., Umerska, A., Zanelli, M. P., Montagu, A., Rossines, E., & Joly-Guillou, M. L. (2016). Synergistic interactions between doxycycline and terpenic components of essential oils encapsulated within lipid nanocapsules against gram negative bacteria. International Journal of Pharmaceutics, 498(1), 23-31.
Wondrak, G., Villeneuve, N., Lamore, S., Bause, A., Jiang, T., & Zhang, D., (2011) The cinnamon-dreived dietary factor cinnamic aldehyde activates the Nrf2-dependent antioxidant response in human epithelial colon cells. Molecules. 15(5): 3338-3355.