Put six people in a room and give them a sniff of the essential oils of peppermint, lemon, and lavender and watch their immediate responses. Peppermint makes many say “candy” as their eyes brighten. With lemon someone will mention cleaning supplies and someone else will talk about lemonade and summer. With lavender many let their eyes close and drift into a restful state. Each of these aromas is distinctive and has been used to treat conditions traditionally for many years and yet each person will have unique associations with the aroma and often personal experiences to recount. Inhalation brings a whole survey of emotions to their faces. Some will initially wince at the strong scent and then, after the initial impact, relax into the moment.
Smell is the most primal of senses and is related intimately to the emotions. There is no thought process between smelling and experiencing so there is no way we can talk ourselves out of the emotion evoked. Conscious knowing is secondary to the experience of smell. Smell triggers chemical reactions that create a whole host of shifts that bring, in very tangible ways (such as the slightly glazed smile while smelling euphoric jasmine) changes in mood states. Research is backing this stuff up. Rosemary for remembrance is being proven in the lab.
The action of aroma on mood has been validated empirically for centuries. But how does this mechanism really work? Popular “aromatherapy” products, such as lavender scented laundry soaps and chocolate cream bath gels, capitalize on the ability of scent to evoke certain states of well-being, contentment, or arousal. However the scientific art of true aromatherapy is based on something more: the specific chemical reactions caused by aroma molecules in the body as well asthe immediate olfactory effect. Aromatherapists advocate using essential oils to manage conditions from insomnia to upset stomach. So if there is increasingly solid replicable evidence behind essential oil chemistry then could we be looking at a viable alternative to mood-altering pharmaceuticals? Could essential oils actually offer a plant-based natural way to manage the ups and downs of life? And if so, what are the mechanisms behind it?
Olfaction, the sense of smell, acts directly on the brain. Imagine taking a deep inhalation of peppermint oil. What happens? It’s theorized the aroma molecules in the essential oil bind with the receptor sites in the olfaction bulbs of the nose, which translates to an electric impulse to the brain, triggering a number of actions and reactions. This electrical impulse acts immediately with the limbic brain, the part of the brain most associated with emotion, mood, altered states of consciousness, and sexuality. Because of this limbic connection the aroma molecules bypass the evolutionarily more modern cognitive brain to work directly on the emotions (Worwood, 1996, pp. 20-21). In the case of peppermint an immediate effect of the crisp menthol aroma molecules is to sharpen attention and enhance focus whereas sweet ylang-ylang slows down processing speed to induce a relaxed state (Moss, Hewitt, Moss, & Wesnes, 2008). Olfaction, according to Worwood, is: “The most direct interface between the brain and the outside world” (1996, p. 19).
So why do certain aroma molecules produce specific effects? Aromatherapist Kurt Schnaubelt, PhD suggests it is chemistry first and scent second. In aromatherapy, he suggests, the reactivity of particular essential oils is based on the structural elements of specific molecules as distinguished by the unique bonding of oxygen and carbon.
There are six functional groups of essential oil components of main import in clinical aromatherapy: alcohols, phenols, aldehydes, ketones, esters, and oxides. Essential oil properties are determined largely by the functional group to which it belongs (Shnaubelt, 1995, pp. 20-21). Alcohols, aldehydes, esters, and oxides are most useful for altering mood.
Alcohols are considered fundamental in clinical aromatherapy because of their versatility. They have virtually no toxicity when used properly, pleasant fragrance, and strong antiseptic qualities. They’re considered tonics.
Aldehydes have a sedative quality that can be used to good effect in aromatherapy blending.
Esters are the most common functional group in aromatherapy with their pleasing and somewhat sweet fragrance. They are sedative, antispasmodic, and calming to the central nervous system (Lavabre, 1990. pp 31-33).
Oxides are strongly expectorant, antiviral, and stimulate the central nervous system (Battaglia, 2007, p. 83).
Knowing the primary constituents of particular essential oils offers a science-based framework for why certain oils work but there are trace elements in many oils that defy classification and may be integral in the condition specific efficacy of particular oils (Battaglia, 2007, p. 84). So scientific language will only take us so far. Tradition and anecdotal evidence offer another language to capture the subtlety of the plant world’s sometimes magical effects on the human body, specifically mood.
So what is mood and why is it important? In this holistic age it’s not productive to speak about a segmented human being. Mind, body, and emotion are intricately linked as a dynamic whole. Our thoughts (mind) evoke emotion/mood, which then literally create our hormonal balance. Dr. Candace Pert’s work in the field of psychoneuroimmunology offers a working hypothesis that proves this rather common-sense link. When we think our bodies allow specific peptides (neurotransmitters and/or hormones) that reflect those thoughts to bond the body’s receptor sites. For example when we think (and feel) calming thoughts euphoria inducing endorphins can lock onto body-wide receptor sites, creating the sensation of health and well-being. Whereas when we experience stressed, angry thoughts and emotions our open receptor sites may be filled with adrenaline thereby creating more tension and fear. Our physical state is a direct manifestation of our emotional state. As Pert says “…your mind is in every cell of your body” (Moyers, 1993, p.182). So emotion, or mood, should clearly be important to everyone, not just those with chronic mood disorders or mental illness. Our culture is stressed and our bodies reflect this state with increased numbers of autoimmune diseases, heart disease, and cancer. Our drug dependence on anti-depressants, tranquilizers, sleeping pills and the like are also reflective of the stressed state too many people live with each moment.
Many popular aromatherapy books offer lists of oils for specific conditions. One book may offer 4-5 oils for, say, depression, while another expert offers 3 additional or even seemingly contradictory oils for the same condition. It’s important to take into consideration the causes of depression when selecting the appropriate oils for treatment. A person who is depressed because of a sudden loss will have very different needs than a person who is chronically depressed whether life circumstances are good or bad. So it becomes important to knowwhy particular oils are allies against depression.
Valerie Ann Worwood offers a number of formulas from the annals of traditional aromatherapy to affect mood. She chose her oils based on common usage to create or relieve specific mood states. We’ll explore her recommendations based on chemical composition and recent laboratory studies to tease out the rudimentary beginnings of why these oils have been used for centuries. We must keep in mind the intricacy of nature is far more vast and complex than anything we can isolate in the lab or replicate in double-blind studies. So with all honor and respect to Mother Nature, let’s explore. We’ll look first at relieving depression and then at promoting concentration.
Depression is popularly defined as a “lowered” mood including sadness, hopelessness, and despair. Energy levels are reduced, sleep patterns are disturbed (ranging from insomnia to sleeping too much), focus is difficult, and eating patterns are erratic (binging and/or starvation cycles). The following essential oils have been traditionally used: Mandarin, Bergamot, Orange, Ylang Ylang, Geranium, Helichrysum, Clary Sage, Lavender, Roman chamomile, Lemon, Grapefruit, Jasmine, Rose Otto, Neroli, Petitgrain, Sandalwood, Marjoram, and Frankincense (Worwood, 1996, p. 145). Reviewing the list the first thing that jumps out is the list is primarily made up of florals: “oils made from the flowers or petals of plants or trees” (Worwood, 1996, p. 253) (Ylang ylang, Jasmine, Lavender, Roman chamomile, Rose Otto, Helichrysum, and Neroli) and fruits: “essential oils that are extracted from the fruit of a plant or tree” (Worwood, 1996, p. 254) (Mandarin, Bergamot, Orange, Lemon, Grapefruit, Petitgrain). This leaves some herbs (Geranium, Clary sage, and Marjoram), a resin (Frankincense), and a wood (Sandalwood). So what constituents make these oils effective in treating depression?
Let’s look at a few of the most popular florals first, Ylang ylang, Jasmine, Rose, and Neroli. Ylang Ylang’s (Cananga odorata) major components are esters. Esters are calming to the nervous system with sedative properties. An overwrought depressive may appreciate the calming effect but someone who barely has enough energy to get up in the morning may need to avoid the sedative aspect by blending with more stimulating oils. Another major constituent of ylang-ylang are ethers, which are antispasmodic and analgesic. Ethers are known for their euphoric effect and may trigger serotonin release (Battaglia, 2007. p.278), which can give the depressed person a needed boost. Ylang-ylang is shown to reduce the stress-response in humans. “At the behavioral level, subjects in the ylang ylang oil group rated themselves more calm and more relaxed than subjects in the control group. These findings are likely to represent a relaxing effect of the ylang ylang oil and provide some evidence for the usage of the ylang ylang oil in aromatherapy such as causing a relief of depression and stress in humans” (Hongratanaworakit, Buchbauer, 2006).
Jasmine (Jasminum officinale) is considered a euphoric with an intoxicating aroma. Jasmine’s major constituents are alcohols, which contribute to its stimulating, tonic effect. Someone who has lost joy for living and is fighting depressive exhaustion can utilize the warming, stimulating effect of Jasmine.
Rose (Rosa damascene) is also traditionally indicated for a number of mood disorders, including depression and anxiety. Its primary constituents are terpene alcohols and according to Schnaubelt: “The unfortunately very expensive rose oil is best used for its fragrance. The scent alone has uplifting and tonifying effects and stabilizes the nervous system.” (1998, p. 87). But that hardly tells the whole story. Rose is one of the most chemically complex essential oils with more than 300 compounds, many of which have not yet been isolated (Battaglia, 2007, p. 255). So while the diverse efficacy of rose is mostly empirical at this time it remains one of the most beloved essential oils for treating mood.
Neroli (Citrus aurantium var. amara) is steam distilled from orange blossoms and is 40% terpene alcohols, specifically cintronellol, which has been shown to have significant sedative effects (Schnaubelt, 1998, p. 41) and 10-20% esters (Schnaubelt, 1998, p. 61). Its main effect is to reduce anxiety and calm the central nervous system.
So while the floral oils are useful for soothing the nerves, inducing euphoria, and reducing stress the citrus oils have very different constituents and effects. We’ll review Mandarin, Bergamot, and Lemon.
Mandarin (Citrus reticulate) contains mainly terpene hydrocarbons and esters. The terpene hydrocarbons, principally limonene, promote antiviral and antiseptic effects that in a subliminal way offer a sense of fresh liveliness. These components are said to be stimulants and “general tonics” (Battaglia, 2007. p. 76). Mandarin’s ester content is unique as it comes from a particular source, anthranilic acid ester, which has a strongly sedative effect that is safe for use even with children (Schnaubelt, 1998, p.77). Mandarin, along with lavender, is considered by many aromatherapists the “children’s remedy” for restlessness, anxiety, nightmares, and worry.
Bergamot (Citrus aurantium ssp. Bergamia) is composed principally of terpene hydrocarbons, alcohols, and esters. The balance of stimulating hydrocarbons with sedating alcohols and euphoric esters makes this an ideal adaptogen or balancer. Bergamot has been used traditionally to refresh and relax thereby inducing a state of focused calm. In a Korean study the combination of Bergamot, Lavender, and Frankincense (1:1:1) in sweet almond oil massaged on terminal hospice cancer patients showed statistically significant improvement in both pain and depression scores (Chang, 2008).
Lemon (Citrus limon), like mandarin and bergamot, is composed primarily of terpene hydrocarbons with their antiseptic, stimulating effects. A study at Ohio State University “provided robust evidence that lemon oil reliably enhances positive mood compared to water and lavender regardless of expectancies or previous use of aromatherapy” (Kielcot-Glaser, Graham, Malarkey, Porter, Lemeshow, & Glaser, 2008).
So the citrus oils’ gift to a depressed individual is gentle, calm stimulation without the jittery effects common with over-the-counter drugs and caffeine. Each citrus has its own character so someone who indicates a need to balance will prefer bergamot whereas someone who is prone to hysterics may do better with mandarin’s sedative calm. And yet another person who simply needs to feel emotionally lifted may be drawn to lemon’s specific positivity.
There are still a few more essential oils left on Worwood’s comprehensive list. Geranium (Pelargonium odorantissimum), an herb, is composed mostly of terpene alcohols with a significant (approximately 25%) number of esters. Like neroli, geranium has a significant citronellol content, which allows for its alert yet calming effect. According to Schnaubelt the mix of tonic alcohols and sedating esters give geranium a unique character that makes its effects very individualized (1998, p. 70). Clary sage (Salvia sclarea), another herb, is composed primarily (up to 75%) of esters, which are known as euphoric sedatives, making this oil beneficial in the treatment of any condition related to lifting mood (Battaglia, 2007, p. 188). Frankincense (Boswellia), a resin, is mostly terpene hydrocarbons, which stimulate and tonify the entire system (Battaglia, 2007, p. 204). And finally Sandalwood (santalum album) is composed of 75% santalols, an alcohol that is said to have a calming, sedative effect (Battaglia, 2007, p. 264).
Our survey of the primary chemical constituents of Worwood’s traditional oils to treat depression indicates flexibility within a standard list. Each of the suggested essential oils has clear benefit for some type or symptom of depression. A possible remedy for someone with jittery nervous exhaustion would be: ylang-ylang, mandarin, and sandalwood. Someone who has lost her will may prefer a more euphoric jasmine, clary sage, lemon, and frankincense blend. And yet another who wishes to balance out mood swings would lean towards neroli, bergamot, geranium, and sandalwood. The options are diverse but therapist understanding of why particular oils are indicated for depression streamlines the art of blending and places sound science in line with a beautifully pleasing art.
Concentration is the ability to focus through any number of distractions, external such as phones, dog’s barking, and children crying, as well as internal brain chatter, web surfing, and procrastination. It’s an immensely useful skill (or gift!) and fortunately there are traditional ways it can be enhanced with essential oils. Worwood suggests the following oils as useful for concentration: Lemon, Lemongrass, Cardamom, Orange, Rosemary, Peppermint, Basil, Bergamot, Cedarwood, and Eucalyptus (1996, p. 99).
With the exception of the citruses (lemon, orange, and bergamot) the oils are distinctly different than those recommended to treat depression. The tonic effects of terpene hydrocarbons in the citrus oils make them naturals for the stimulating warmth required for concentration. So we’ll review the constituents of the most common oils recommended for focused alertness and concentration: rosemary, peppermint, and eucalyptus.
Rosemary (Rosmarinus officinalis) has three main chemotypes. The most common in aromatherapy is the cineole type. Its main component is cineole, an oxide. Oxides are known for their expectorant properties and 1.8 cineole found in rosemary is cited as the constituent “responsible for rosemary’s CNS-excitatory properties” (Battaglia, 2007, p. 83) and terpene hydrocarbons, which are known for their tonic effect. Traditionally rosemary is said to stimulate the mind and help with memory. A UK study recently validated this in the lab: “Rosemary produced a significant enhancement of performance for overall quality of memory and secondary memory factors, but also produced an impairment of speed of memory compared to controls” (Moss M, Cook J, Wesnes K, Duckett P., 2003). And in regards to mood: “both the control and lavender groups were significantly less alert than the rosemary condition; however, the control group was significantly less content than both rosemary and lavender conditions. These findings indicate that the olfactory properties of these essential oils can produce objective effects on cognitive performance, as well as subjective effects on mood” (Moss M, Cook J, Wesnes K, Duckett P., 2003). So, indeed, rosemary does aid memory and enhances mental clarity.
Peppermint (Mentha x piperita) is composed principally of menthol (up to 46%) with the associated alcohol tonic effect. The above referenced study (page 3) by Moss, et al indicated peppermint stimulated cognitive functioning as opposed to ylang-ylang, which slowed processing time (Moss, Hewitt, Moss, &Wesnes,2008). Not entirely unrelated to concentration peppermint is also shown to relieve headaches and: “prevent congestion of blood supply to the brain” and cold compresses of peppermint oil are recommended to reduce headache and migraine (Battaglia, 2007 p. 247). While headaches are not directly related to concentration they can certainly distract! By including peppermint oil in a concentration blend the unfortunate occasional by-product of focused work, the headache, can be avoided.
Eucalyptus has at least 600 different species and at least 13 different essential oil types. For our purposes we’ll review Eucalyptus radiata, which is 65-75% cineole content (Battaglia, 2007, p. 192) with the remaining principle components terpene alcohols. Like rosemary cineole oxide stimulates and terpene alcohols tonify. Aside from Worwood’s list eucalyptus is rarely indicated for mood but more often for its expectorant and antibacterial qualities. However its distinctive, clearing odor may well serve to bring the mind to rapid attention regardless of chemistry.
So while the essential oils traditionally associated with depression have euphoric, sedative, and calming effects via their ester, ether, and alcohol contents the essential oils associated with concentration are heavier in oxides and terpene alcohols. The aromas of florals are rich, warm, and gently supportive whereas cineole-rich rosemary and eucalyptus are crisp and clearing. Citrus oils are useful for both depression and concentration with their stimulating uplift.
Much of aromatherapy’s elegance is the synergy between different oils. Blending lemon with clary sage and jasmine creates a different effect (uplifted euphoria) than blending lemon with rosemary and eucalyptus (crisp awareness) and yet the component ‘lemon’ is an integral part of each blend.
This synergy offers more freedom than the pharmaceutical approach to treating ‘disease’. Pharmaceuticals for mood are suddenly common as candy and many client intake forms are filled with lists of anti-depressants, sleeping pills, and pain relievers. While pharmaceuticals have their place often they’re unnecessary and evidence of a cultural reliance on chemicals to “fix” us. With laboratory studies suggesting the efficacy of traditional remedies, including aromatherapy, we can explore viable alternatives to pills. This encourages active engagement of the client/patient in his/her own health and well-being. And aesthetically the application or inhalation of a blend of essential oils pleases the senses and engages the imagination while the chemical constituents work their “magic” to alter mood and promote well-being. That’s good medicine.
Battaglia, Salvatore. (2007). The complete guide to aromatherapy. Brisbane, Australia: The International Centre of Holistic Aromatherapy.
Chang, SY. (2008). Effects of aroma hand massage on pain, state anxiety and depression in hospice patients with terminal cancer. Department of Nursing, Keimyung University, Jung-gu, Daegu, Korea. Abstract obtained fromhttp://www.pubmed.gov.
Hongratanaworakit, T, Buchbauer, G. (2006). Relaxing effect of ylang yang oil on humans after transdermal absorption. Phytother Res. 2006 Sep: 20(9): 758-63. Abstract obtained from http://www.pubmed.gov.
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Moss, M Hewitt, S Moss, L, Wesnis, K. (2008). Modulation of cognitive performance and moods by aromas of peppermint and ylang-ylang. Int J Neuroscience. 118:(1):59-77. Abstract obtained fromhttp://www.pubmed.gov.
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