An essential oil is a concentrate of the aroma compound(s) of a plant. They are so named because they contain the "essence" of the plant's smell, and not because they are "essential" to human health.
Usage and efficacy
Note that these products are sometimes advertised as having woo effects other than listed below.
- Camphor, eucalyptol, menthol, eugenol and methyl salicylate are a category of chemicals found in essential oils like mint, clove and wintergreen. They are decent topical analgesics and moderately effective decongestants, because they produce a cold sensation, particularly in the lungs when inhaled, due to their action on ion channels in tissue. They are also used to flavor food and tobacco products, but they are toxic in large doses.
- Citronella oil, distilled from Cymbopogon spp. (lemongrass), is a decent insect repellent.
- Thymol is found in thyme and many other essential oils. It is used to treat helminth infections and is also a decent pesticide.
- Refined limonene, found in citrus oil, is an excellent degreaser for metal automotive/appliance parts in low concentrations, and a decent paint stripper in high concentrations. Also used as an insecticide because it's very toxic.
- Linalool is an important chemical intermediate in the production of vitamin E. It's also an effective pesticide against flies and cockroaches (but not mosquitoes).
- Witch hazel is an essential oil that produces a pleasant astringent sensation when applied topically and has a moderate antiseptic effect.
- Tea tree oil contains various various terpenes, pinenes, cineoles and alcohols that give it a fresh, cooling scent. It's a decent decongestant when inhaled and shows some promise as a topical antiseptic, but studies are inconclusive. However, it's toxic in large doses, can cause serious allergic reactions, and it's less effective than options that are a fraction of the cost. But it does smell... really nice... or like a toilet cake (depending on who you ask).
- Alternative medicine is big on essential oils for all kinds of nonsense uses, many of which are very dangerous. *Have a look at our list of medicinal plants for examples of specific plants.
- Anything from Young Living or their bastard stepchild doTerra.
- Aromatherapy often uses essential oils because they're concentrated (more smell = more health).
- In the panchakarma practice of the pseudoscience known as Ayurvedic medicine, patients are made to ingest the (sometimes quite toxic) essential oils.
Safety and adverse effects
Essential oils are highly concentrated mixtures of chemicals. They can potentially cause an allergic reaction or be toxic in large doses. Some essential oils can consist primarily of a single chemical compound. For example, mustard oil can consist of up to 92% allyl isothiocyanate (>90% is usually considered a technical grade, the lowest commercial purity offered by chemical companies).
Essential oils are applied in one of three ways: the English school of diluting in vegetable oil and massaging on the body (topical), the French school of ingestion, or the German school of inhalation. From a toxicological perspective, these three routes of administration range from lowest risk (topical) to highest risk (inhalation) for adverse effects for the same compound and dosage. Because essential oils are concentrated, they have an increased risk of adverse effects compared to the herbs from which they were derived.
The big problem is that believers in "alternative medicine" tend to believe that essential oils are devoid of potential for harm because they're "natural". This has led to some people dying or falling ill as a result of using them. One woman suffered second- and third-degree burns after applying doTerra essential oil before getting in a tanning bed. Essential oils may often be labeled as cosmetic goods, freeing them of the obligation of at least some countries' federal regulations. This exemption can vary by country and by the claims made by the specific retailer, but at least in the US, anyone can sell an essential oil by itself along with a Quack Miranda Warning, even potentially toxic oils like bitter almond oil. Unprocessed bitter almond oil can be >95% benzaldehyde, but it also contains the poison cyanide.
A review of adverse effects from essential oils used in aromatherapy reported a total of 71 adverse events. The adverse effects primarily consisted of dermatitis, but included one death (from wintergreen oil). Lavender (Lavandula spp.), peppermint (Mentha × piperita), tea tree (Melaleuca alternifolia) and ylang-ylang (Cananga odorata) were the most common oils associated with adverse events. Additionally, 5 deaths have been associated with pennyroyal (Mentha pulegium) extracts.
Some books have recommended treatment of serious diseases with essential oils (e.g., cancer, bacterial pneumonia, arteriosclerosis, and high blood pressure). This is particularly problematic when the disease sufferer forgoes safe and effective medical treatment (i.e. medical treatment whose risk vs. benefit has been evaluated) for what are likely to be ineffective essential oils that may or may not be safe.
Essential oil usage can be a focal point for crank magnetism. For example, the 3rd edition of the Essential Oils Desk Reference uses testimonials and appeal to ancient wisdom (Bible quotes, Napoleon and Hildegard of Bingen) for justification. The book describes using essential oils in conjunction with foot reflexology, acupuncture, the "lymphatic pump" (an osteopathic technique), cleansing, immune system boosting, pH balance among others. The book is against water chlorination despite it having been shown to be a safe and effective means of disease prevention. The book also tacitly supports the antivax movement by describing treatments for commonly preventable childhood diseases, which no child should need unless they weren't getting vaccinated (e.g., diphtheria, whooping cough, measles, mumps, chicken pox, and yes, even polio!). Some of the crankier ideas in the 3rd edition were probably removed from later editions of the book after the publisher closed down and sold publishing rights and back stock to Life Science Publishing, though the older editions remain popular.
- Olive oil is used for anointing in the Mormon church
- Herbs are mentioned in the Mormon Doctrine and Covenants for healing
- The apparent propensity for Mormons to engage in MLM schemes.
- Use of essential oils by Mormon women may be a means for them to attain power via healing within the Church, since women are not allowed into the priesthood.
- dōTERRA — a Mormon MLM essential oil company
- Young Living Essential Oils — an MLM essential oil company from Lehi, Utah (a city that is 89% Mormon). Young Living got into an odd legal battle with dōTERRA in 2014 over mutual allegations of adulteration with synthetic chemicals.
In 2014, dōTERRA and Young Living Essential Oils were warned by the FDA against making unsubstantiated medical claims for treatment of diseases. dōTERRA was accused of unsubstantiated claims for treatment of "viral infections (including ebola), bacterial infections, cancer, brain injury, autism, endometriosis, Grave's Disease, Alzheimer's Disease, tumor reduction, ADD/ADHD, and other conditions that are not amenable to self-diagnosis and treatment by individuals who are not medical practitioners." Young Living was accused of unsubstantiated claims for treatment of "viral infections (including ebola), Parkinson’s disease, autism, diabetes, hypertension, cancer, insomnia, heart disease, post-traumatic stress disorder (PTSD), dementia, and multiple sclerosis…"
- Mustard essential oil information
- Essential Oils Desk Reference, Essential Science Publishing, 3rd ed., 519 pp. 2006. ISBN 0943685397.
- The Truth Behind Aromatherapy Schools of Thought August 9, 2014. Atlantic Institute of Aromatherapy.
- Adverse effects of aromatherapy: a systematic review of case reports and case series by P. Posadzki et al. Int. J. Risk Saf. Med. 2012 Jan 1;24(3):147-61. doi: 10.3233/JRS-2012-0568.
- Woman with third-degree burns warns against essential oils: 'It's been hell'
- Albert Vieille: Bitter Almond Essential oil Morocco
- The Good Scents Company: bitter almond oil
- Macht, David I. (1913). "The Action of So-Called Emmenagogue Oils on the Isolated Uterus with a Report of a Case of Pennyroyal Poisoning." Journal of the American Medical Association LXI(2):105-107.
- Sullivan, John B. (28 December 1979). "Pennyroyal Oil Poisoning and Hepatotoxicity". JAMA 242 (26): 2873–2874.
- Editorial. (1909). "Medicolegal: Pyemia, "Pennyroyal Pills" and Evidence in Abortion Case. JAMA LIII(11): 891.
- Young, Gordon. (1995). "Lifestyle on Trial." Metro: Silicon Valley's Weekly Newspaper.
- See the Wikipedia article on Mentha pulegium.
- The Complete Book of Essential Oils and Aromatherapy by Valerie Ann Worwood (1991). New World Library. ISBN 0931432820.
- Disinfection with Chlorine Centers for Disease Control and Prevention
- [http://archive.is/URZrs Archived copy of availability of editions 1 and 2 from Life Science Publishing (September 19, 2016).
- Life Science Publishing
- Archived copy of Amazon page for Essential Oils Desk Reference, 3rd Edition (September 19, 2016).
- Handbook 2: Administering the Church. 20.5 Consecrating Oil
- Doctrine and Covenants Section 42 See line 43.
- Why Do so many Mormons enter MLM schemes? August 07, 2006. Notamormon blog
- Could someone please explain to me the Mormon fascination with 'essential oils', à la 'DoTERRA'? r/exmormon blog
- Mormons and Essential Oils
- dōTERRA: From Corporate to Consultant, Michael & Becky Cox
- Young Living Essential Oils
- [http://www.bestplaces.net/religion/city/utah/lehi Lehi, Utah: Religion
- Damning Evidence That Young Living and DoTERRA’s Essential Oils are Adulterated by Arvid Keeson (August 15, 2014) Utah Stories.
- Report Used in Young Living Farms Case Against DoTERRA Suspect by Richard Markosian (August 21, 2014) 'Utah Stories.
- FDA warns three companies against marketing their products as Ebola treatments or cures by Abby Ohlheiser (September 24, 2014) Washington Post.
- dōTERRA International, LLC 9/22/14 September 22, 2014 FDA.
- Young Living 9/22/14 September 22, 2014 FDA.