It’s a fact that essential oils have been used in various therapeutic applications for centuries, but there has generally been little published clinical research on their use. So we don’t have much hard data on their effectiveness in alleviating or attenuating the various conditions they are utilized in traditional medicine to treat. But this is starting to change lately, as a little spattering of scientific studies on essential oils are being conducted around the world.
There are a quite a few inherent difficulties for any study centered on essential oils. For one thing, that shit ain’t standardized. Unlike with a pharmaceutical drug, medical researchers can’t count on the fact that the chemical constitution of, say, lavender oil is exactly the same in all cases. The chemistry of an essential oil is inevitably going to be influenced by local geographical conditions, and weather conditions, as well as the season and the goddamn time of day when the plants are harvested. Additionally, how they are processed, and how they are packaged and stored, will affect the oils’ constitution. Each plant is unique in its chemistry, so essential oils are never exactly the same—this is obviously different from pharmaceutical drugs that are synthetically reproduced and are identical every time. It throws a wrench in the works when you’re studying something, if you can’t be sure that thing is, on a chemical level, exactly what you think it is.
Another problem is derived from the fact that it is difficult to conduct blinded studies with aromatic substances. Typically, research studies involve testing two groups—one group gets the experimental substance, whatever that may be, and another group gets a placebo substance (this group is referred to as the “control” group). When using aromatic substances, it is very difficult to conduct a blinded study, for the exact reason you would think. Basically, your subjects in a study are going to know whether you’re giving them a fucking beaker of lavender oil to sniff, or a beaker of saline solution.
But some researchers are finding ways to get around these difficulties, and conducting clinical studies on essential oils.
Preliminary controlled studies indicate that various forms of aromatherapy may have clinical applications in the reduction of anxiety experienced by patients with Alzheimer’s disease and other forms of dementia. For instance, one interestingly designed (albeit small-scale) study, a hospital ward was suffused with either lavender oil or water for two hours. An investigator then entered the ward and evaluated the behavior of the 15 residents, all of whom had dementia. (The investigator was unaware of the study’s design and wore a device to block inhalation of odors, because double-blind medical studies require both the researchers and the study-percipients to be unaware of whether the actual substance or the placebo has been delivered.) The results indicated that use of lavender oil aromatherapy modestly decreased agitated behavior.
It’s common, however, for patients suffering from dementia to lose their sense of smell, rendering the application of aromatherapy in dementia patents somewhat limited in its usefulness.
Essential oil of lemon balm has shown promise in this regard; in a double-blind study of 71 people with severe dementia, use of lotion containing essential oil of lemon balm reduced agitation compared to placebo lotion.
In a trial involving sixty-six women waiting to undergo highly anxiety-inducing surgical procedures, ten minutes of inhaling the aromas of essential oils of vetivert, bergamot, and geranium failed to reduce anxiety significantly, compared to placebo treatment. In another study, rosemary oil failed to reduce tension during an anxiety-provoking task, and conversely might have actually increased anxiety.
Another interesting complication involved in studying aromatic substances, is that human beings have a strong connectivity in our brains between memory and smell. Smells pull up a lot of emotional associations for us—it’s such an accepted fact that neurologists even have a pithy name for it: “nasal nostalgia.” So, if a subject smells rosemary and becomes anxious, how can a researcher possibly know if that’s due to some innate property of rosemary oil, or because that subject has just been reminded of the rosemary perfume his crazy aunt Mildred used to wear—the one who used to chase him around the house with her taxidermy cat when he was a child?
Yet another wrench in the works.
Still, some other clinical trails have actually revealed favorable effects. In one such study, researchers assessed the anxiety-level in three-hundred and forty individual dental patients, all waiting for dental appointments (who were all presumably about to flip their shit.) Those that inhaled the scent of lavender showed lower levels of anxiety compared to the control group. In another study, one-hundred and fifty patients were randomized into one of three treatment groups: control (standard care), standard care plus lavender, or placebo (standard care plus another kind of oil not thought to have any anti-anxiety effects). Those in the lavender group did actually experience an appreciable reduction in their level of anxiety.
Approaching the use of essential oils from a different angle, researchers have evaluated the effects of massage therapy done with essential oils on people suffering from anxiety and/or depression, while undergoing treatment for cancer. The treatment did appear to provide some short-term benefits to those patients. Again, absorption through the skin may have played a role here.
There is weak evidence to suggest that inhaled peppermint oil might relieve postsurgical nausea. Peppermint was associated with the attenuation of nausea symptoms in a small randomized trial of 35 women after nonemergency cesarean section, compared to placebo aromatherapy and standard antiemetic drugs.
Inhaled peppermint oil may also be useful in relieving mucus congestion of the lungs and sinuses—there is, however, only marginal supporting evidence for this application.
There is clinical research showing that an essential oil constituent (perillyl alcohol) has been successful in treating brain cancer. That’s a pretty frigging big claim, and calls for linkage:
So we know that in certain circumstances the constituents of essential oils can do big things. But that doesn’t necessarily display the effectiveness of the essential oils themselves—for instance, does inhalation necessarily lead to the same effects as other modes of administration? Maybe. Or maybe not.
In one rat study, bergamot essential oil inhibited the damage caused by “focal ischemia” (the same type of damage caused by stroke). The oil was injected, not inhaled.
Persistent anxiety is an all-to-common problem in the general population, and the pharmacological drugs used to treat it can often lead to sedation—hence the perennial search for alternative modes of treatment. Since the anxiolytic properties of lavender have already been demonstrated in some studies and small-scale clinical trials, like we’ve been looking at, a controlled clinical study was performed to evaluate the efficacy of “silexan,” an oral lavender oil capsule preparation. The lavender oil preparation was shown to be roughly as effective as pharmaceutical drugs (benzodiazepine) in the treatment of anxiety.
So what does all this say? Nothing other than what it says. There’s no broad, all-or-nothing take away, like “essential oils work!” or “essential oils don’t work.” (Sorry not to have a magic answer.) As time goes on, more and more evidence will be amassed both to debunk the effectiveness of oils in some applications, and to support their effectiveness in others.