You probably have seen these little bottles on shelves of natural-food stores. Lavender oil, for example, is marketed as a stress reliever and sleep agent. Tree tea oil is promoted for its antiseptic and anti-inflammatory uses. Oil of peppermint is often sold as a digestive aid. But do they work? And are they safe to use?
Essential oils explained
Essential oils are highly concentrated extracts of flowers, leaves, stems, roots, seeds, bark, resin, or fruit rinds.
Aromatherapy is the practice of employing these essential oils, usually by inhaling them or rubbing them on the body during a massage. These are meant to yield health benefits.
Essential oils can be distributed or applied using many methods, such as room diffusers, individual inhalers, steam inhalation, bath salts, patches, compresses, dressings, and massage products.
In the healthcare setting, aromatherapy is increasingly common in hospitals, nursing homes, and hospice care, usually administered by nurses, to relieve patients’ symptoms.
As is the case with other therapies, limited well-designed clinical trials involving the effects of essential oils on humans have been conducted and published; studies often have had too-small sample sizes or had too many limitations to be conclusive or generalizable.
Although essential oils research has increased dramatically in recent years, mechanisms of action for its effects are still somewhat unclear.
Still, research suggests potential clinical applications, including reducing stress and nausea in people with cancer, behavioral issues in people with dementia, and symptoms of anxiety and depression, as well as caring for patients with open wounds or incisions.
Several studies have suggested that the antimicrobial properties of tea tree oil, for example, can be helpful in treating bacterial infections of the skin that are common among hospitalized patients.
What the experts say
In the more than 20 years since she started researching essential oils and teaching a graduate-level course on aromatherapy at the University of Minnesota, Linda Halcón, Ph.D., has seen interest in the aromatic oils’ health benefits dramatically increase. And that has been both good and bad.
Halcón is troubled by some of what she sees, such as merchants who sell essential oils offering directions on how to ingest the oils, especially since some essential oils, including oil of wintergreen and eucalyptus oil, can be toxic if swallowed, even in small amounts.
Then there’s false advertising, with not only unsubstantiated claims about what the oils can treat but also mistruths about exactly what you’re getting.
“I’ve been very concerned about the marketing,” Halcón says. “I often see claims that a product is ‘therapeutic grade.’ The problem with that is there is no independent body that goes around certifying products as therapeutic grade. That just means the company selling the oil has declared it as such.”
Halcón believes essential oils can be beneficial when used moderately and for a specific purpose—for example, using lavender or lemon oil as a mood booster. “I tend to be pretty conservative,” she says. “I don’t want people to have adverse effects and ruin it for everyone.”
If you’re considering using essential oils, here's how to do so safely.
Talk with your provider
While it’s difficult for healthcare providers to know everything about the multitude of essential oils out there, it’s imperative that you tell your provider you’re using them so he or she can help you avoid interactions with medication or other treatment.
For example, if you have a health condition, such as an irregular heartbeat, that makes taking stimulants dangerous, avoid oils such as peppermint, rosemary, and basil, Halcón says.
Eucalyptus can interfere with certain cancer medications, wintergreen may interact with anticlotting drugs, and peppermint could have negative effects on patients taking seizure drugs.
Your provider will likely remind you that using essential oils is recognized as a “complementary” therapy, or therapy that can be added to a larger system of treatments.
For the most part, they’re not substitutes for conventional care, nor are they approved by the U.S. Food and Drug Administration to treat any conditions.
Dilute before applying
According to Halcón, essential oils are about 100 times more potent than their whole plant form. Not following dilution directions when using them on the skin can result in a severe rash or even burns.
Essential oils are usually diluted with a “base” or “carrier,” which might be a vegetable oil or a fixed oil from nuts, seeds, or trees such as coconut or jojoba.
Using a carrier decreases the concentration and “dose” and protects the skin from a reaction. Other precautions to take when handling essential oils:
• Never dilute essential oils in bathwater without a dispersant, or a substance that helps water and oil mix more easily. Without this, you could end up with a 100 percent concentration on your skin. Instead, mix the essential oil first with Epsom or bath salts.
• Never apply any essential oil to the delicate eye area or mucus membranes. Unless you have had training in aromatherapy, be cautious in applying essential oils to broken skin or any inflammatory or allergic skin condition.
• Stop using essential oils if you develop an allergic reaction. A reaction called dermal sensitization can cause redness or blotchiness, which can occur on first use or after many uses.
• To avoid sensitization, don’t apply oils to the same area of skin every day.
• Apply citrus oils to your skin in moderation, if at all. “You should be careful using most citrus oils on the skin, even in low concentrations, because photosensitivity reactions can be triggered,” Halcón says.
“If you do use citrus oils on your skin, stay out of the sun or avoid exposing that area of the body to the sun for 12 to 18 hours after you apply them. Not doing so can result in serious burns.”
• When using a vaporizer to disperse the scents, you can use the oils full strength or dilute them, depending on how strong you want the fragrance to be and the type of diffuser used. Follow the directions.
Don’t ingest oils
Some aromatherapists may advise ingesting essential oils in addition to applying them topically, according to a 2012 study on adverse effects of aromatherapy. Never ingest an essential oil unless you have extensive training.
Certain essential oils, such as wintergreen, can be toxic to the liver. Wintergreen contains high amounts of salicylic acid, which is the anti-inflammatory ingredient found in aspirin. The National Capital Poison Center (better known as Poison Control) in Washington, D.C., says that ingesting oil of wintergreen is equal to swallowing a large number of adult aspirin tablets.
Vanderbilt University Medical Center’s Tennessee Poison Center reports that the incidence of accidental poisoning from essential oils, such as tea tree, doubled between 2011 and 2015, and four in five victims were children. Symptoms of severe overexposure can include agitation, drowsiness, hallucinations, seizures, chemical burns, breathing problems, liver failure, and brain swelling.
If you’re using essential oils, be sure to keep them locked up on a high shelf out of a child’s reach.
Treat them right
“Essential oils will begin to oxidize after they’re opened and exposed to heat, light, or air,” Halcón says. “This changes the chemical composition and increases the risk of allergy and skin irritation.”
To minimize oxidation, keep essential oils in their dark glass bottles with a tight-fitting lid—not a dropper cap—in the refrigerator or another cool, dark place for no longer than one to two years. Open only when necessary, and replace the cap immediately after using.
Understandably, you might find it hard to discard an expensive essential oil. But when that time comes, resist the urge to pour it down the drain. Empty the bottles outdoors on paper towels or cardboard and then discard or recycle as you usually do.
Finally, the National Association for Holistic Aromatherapy warns that essential oils can be highly flammable, so keep them away from open flames, such as candles, matches, cigarettes, and grills.
The bottom line
Essential oils have been shown to have therapeutic benefits but shouldn’t take the place of conventional medications and treatments, and you should never ingest them.
If you’re interested in trying aromatherapy, use essential oils only as directed, and watch for any skin irritations or other problems that may arise after use.