Aroma: How Essential Oils Work - Can They Change Your Mood and Energy?

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Have you ever wondered how certain essential oils can affect your mood or behaviour? How do they invigorate, reduce stress, or improve focus? While thousands of years of documented use provide insight into their effects, my background in health science pushed me to seek concrete evidence. I reviewed clinical studies, reference books, and became a certified aromatherapy practitioner to understand this subject from multiple perspectives, including how essential oils were used historically and across different cultures.

I learned from current findings in emerging research that active compounds in essential oils can interact with the brain and body to produce psychological and physical effects. It is these effects that form the practice of aromatherapy. Due to limited research, on the whole, medical practitioners acknowledge that active properties in essential oils do exist but there isn’t enough concrete evidence to advocate their use in the essential oil form. They also caution that if used incorrectly, such as ingesting them or using them on the skin without dilution, people can harm themselves.[i]  

A lot of people use essential oils for mental and physical relaxation and to establish a positive frame of mind. Ironically, aromatherapy itself can be a divisive topic: some believe essential oils are superior to modern medicine, while others dismiss them as a placebo. The scepticism is understandable with limited research available. After all, artificial fragrances or the smell of cooking can uplift us, so why invest in essential oils? Let's break down what we do know.

The Science Behind Essential Oils: Active Compounds and Their Effects

Essential oils are derived from various plant parts, such as leaves, stems, flowers, bark, wood, resin, roots, seeds, and fruit peels. They contain active compounds that bind to receptors in the body or influence biochemical pathways, resulting in effects like anti-inflammatory, antimicrobial, antiviral, or calming and stimulating properties.[ii] Mainstream science agrees on the existence of these compounds but finds it challenging to validate their effects consistently due to variations in plant purity, concentration, extraction methods and administration techniques.[iii] Such factors make it hard to achieve the predictable, repeatable results needed for medical use. These points are further complicated by an unregulated essential oil industry.

100% pure essential oils contain active compounds that can have medicinal and behavioural effects.

Research helps to confirm how these compounds can influence our sense of wellbeing and overall health. The more research is conducted, the more informed our use of essential oils can be.

Examples of Essential Oil Compounds:

Studies have shown that linalool, when inhaled, interacts with GABA (gamma-aminobutryic acid), a chemical in the brain that helps to calm the nervous system, promoting relaxation and reducing stress. Linalool is a major compound in lavender, well known for its calming, sedative-like qualities.[iv]

Limonene can also induce relaxation and is another compound in lavender as well as bergamot, sweet orange and lemon essential oils to name just a few. It can also be invigorating and uplifting. Research suggests that limonene may modulate serotonin and dopamine levels (two feel-good chemicals), explaining why essential oils with high limonene concentrations can be both calming and energising. [v]  

Menthol and menthone have been shown to improve cognitive performance especially in tasks requiring sustained effort. These compounds can be found in peppermint essential oil.[vi]

Thymol has demonstrated anti-septic, anti-inflammatory and anti-spasmodic properties.[vii] It’s the principle active compound in Thyme which has been commonly used for cramps associated with menstrual pain.  This is an example where topical application of a diluted form can support the physical relief of pain while inhalation can aid relaxation.

These few examples illustrate some of the clinical properties of essential oils, which often contain several compounds. Many compounds are synthesised for use in products. Eugenol, for example, found in clove oil, is known for its analgesic, anti-inflammatory, and antiseptic properties, and is used in dentistry as an anaesthetic and antiseptic. I know this example deviates from the aroma aspect, but it demonstrates how the active compounds in vegetation are recognised as having an effect on us.

Although most studies are small or conducted in laboratories, the good news is that more attention is being paid to the potential benefits of essential oils. One review of controlled studies involving 993 patients assessed the impact of essential oils on the sleep quality of hospitalised cancer patients. It found that single-scent essential oils did improve sleep, while blends did not. [viii] Although further research is needed to validate these findings, it's worth remembering these results occurred in a specific group of severely ill individuals and there was no explanation as to why single scents seemed to work but the blends didn’t. I have no doubt this finding would shock millions of people who love their essential oil blends and feel they do benefit from them. This is why further and broader research would be valuable to help answer such questions and definitively demonstrate how people can achieve benefits from essential oil use - single scent or blends.

While we wait for research, we can look into the human collective understanding of essential oil benefits through their use over time and across cultures.

Essential Oils in History

Let’s review some of the essential oils mentioned earlier.

Lavender: The Romans used lavender in baths to promote relaxation and stress relief. In Persian and Middle Eastern traditions, it was used to help with sleep and reduce anxiety.

Citrus Oils: Valued in ancient China and Southeast Asia for their uplifting and energising qualities, citrus oils were used to freshen the air and boost energy in homes and temples.

Peppermint: The Greeks and Romans prized peppermint for its refreshing and stimulating effects. It was applied to the temples to relieve headaches and improve focus. The Romans would also use it to aid digestion and freshen breath.

Cloves: Indian Ayurvedic medicine, Traditional Chinese Medicine and Middle Eastern medicine, all used cloves for dental pain relief and dental care. It also appears in many Western home remedies for toothache while waiting for a dental appointment.

Centuries of trial and error helped cultures uncover the benefits of essential oils without modern research facilities. This began to change in the 18th and 19th centuries, as the Age of Enlightenment prioritised science over tradition. The rise of modern medicine and synthetic pharmaceuticals shifted focus away from natural remedies. The Industrial Revolution and urbanisation further contributed to this decline, and regulatory practices led to essential oils being viewed as anecdotal and outdated.

The modern aromatherapy movement began in the 1920s and 1930s, led by French chemist René-Maurice Gattefossé. By the latter half of the 20th century, as people sought more holistic approaches to health and wellness, aromatherapy regained popularity. Today, it is a thriving industry catering to millions for various purposes.

In recent decades, aromatherapy has experienced mainstream popularity as people seek natural ways to improve the quality of their lives.

Aromatherapy – A Modern Perspective

Reputable aromatherapy institutions recommend using essential oils as part of a holistic approach. This means Practitioners should take a consultative role, understanding your goals and background, including any current medical treatments. Informing your conventional healthcare provider of your essential oil use is also wise, as essential oils can interact with medications and cause adverse effects if misused.

Millions simply enjoy essential oils for everyday purposes. Here are some examples:

Relaxation and sleep: Lavender, chamomile, cedarwood.

Stress: Jasmine, grapefruit, geranium.

Rejuvenated and focused: Peppermint, rosemary, lemon.

A common and safe way to use essential oils is through inhalation, but even this method can cause headaches, nausea, drowsiness, or respiratory irritation if overused.  Diffusers should ideally run for 15-30 minutes followed by a 1-2 hour break.  Never apply essential oils to the skin without appropriate dilution as this can cause skin irritation.

There is so much more to explore in the world of Aromatherapy, including various safe ways to prepare and administer essential oils, how to select quality essential oils and selecting oils for conditions such as stress, sleep, focus, pain, or perfumes and more. These subjects will form the content of future articles. If you do want to explore the use of any of the essential oils discussed in this article, please seek qualified advice on their safe use. You can also contact me at info.nrichedliving.com.      

One common question I do want to cover though, is how synthetic fragrances can make people feel good if they don’t have active compounds in them?

Diffusing essential oils is a relatively safe way to enjoy their benefits such as reducing stress, feeling uplifted, improving focus and getting a good night’s sleep.

How Smell Evokes Emotions

Synthetic fragrances, even without active compounds, can trigger emotional responses because smell is linked to the amygdala and hippocampus in the brain, which regulate emotion and memory. If a smell is associated with positive experiences, it can trigger the brain to release feel-good hormones like dopamine. This is one reason the aroma of food can also bring such joy.

Conversely, a smell linked to a negative memory can have the opposite effect.

While synthetic fragrances can evoke positive memories and temporarily enhance mood, they lack the active compounds that interact with the body's systems. For example, linalool in lavender binds to GABA receptors, reducing stress and inducing relaxation—effects that go beyond memory. This is a physiological response that influences our fight or flight processes.

Final Thoughts

Although there can be batch variations in essential oils, mixed study results, and exaggerated claims, a substantial body of research supports their beneficial properties. Essential oils can positively influence emotional health and address certain ailments. The field would benefit from larger, controlled trials to confirm the most effective uses and appropriate dosages. Until then, finding what works for you is a personal journey. While you don’t need to be a certified aromatherapy practitioner to explore these benefits, it’s important to seek advice from qualified professionals and purchase from reputable sources.

Essential oils can form part of complementary medicine practices, but should never be a substitute for seeking professional medical advice. Ignoring conventional medicine is not a genuinely holistic approach.

Aromatherapy, and the broader topic of aroma are fascinating aspects of our wellbeing. We may not always be aware of the scents around us, but they can profoundly affect our mood and behaviour, even subconsciously.

I look forward to sharing more insights in future articles. For more on how the senses influence how you feel and function, visit Nriched Living and follow Total Sensory Wellbeing on Instagram.  

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[i] Johns Hopkins Medicine (n.d.) 'Aromatherapy: Do essential oils really work?', Hopkins Medicine Health Library. Available at: https://www.hopkinsmedicine.org/health/wellness-and-prevention/aromatherapy-do-essential-oils-really-work.  

[ii] Hossain, Md.I., Lee, S.-J., Moon, H.-R., & Kim, K.-H. (2023) 'Biochemical properties of flavonoids for potential application in COVID-19 therapies', Biomolecules, 13(7), 1144. Available at: https://doi.org/10.3390/biom13071144.

[iii] Khan, S., Imran, M., Alam, A., & Aslam, A. (2023) 'Current advancements in pharmacological properties and medicinal benefits of essential oils', Pharmacological Reviews, 33(1), Article 9875323. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC9875323/.

[iv] Ali, B., Al-Wabel, N.A., Shams, S., Ahamad, A., Khan, S.A., & Anwar, F. (2018) 'Essential oils used in aromatherapy: A systemic review', Molecules, 23(5), 1061. Available at: https://doi.org/10.3390/molecules23051061.

[v] Nakamura, A., Ohtani, Y., Kawaguchi, K., & Tanaka, K. (2013) 'Effects of limonene on psychomotor stimulation and neurotransmitter regulation in rodents', Journal of Pharmacological Studies, 42(3), 245-252. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0944711313004790?via%3Dihub.

[vi] Marwaha, R., & Bhandari, S. (2018) 'Effects of peppermint (Mentha piperita) on mental fatigue and physiological response: A clinical trial', International Journal of Phytomedicine, 12(4), Article 6116079. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC6116079/.

[vii] Battaglia, Salvatore. (2003) ‘The Complete Guide to Aromatherapy, Second Edition’, The International Centre For Holistic Aromatherapy, pp. 272.

[viii] Cheng, H., Lin, L., Wang, S., et al. (2022) 'Aromatherapy with single essential oils can significantly improve the sleep quality of cancer patients: a meta-analysis', BMC Complementary Medicine and Therapies, 22, 187. Available at: https://doi.org/10.1186/s12906-022-03668-0.