The Effects of Essential Oils on the Nervous System: A Scoping Review

Summary & key facts

This scoping review looked at research from 2012–2022 on how essential oils affect the nervous system. The authors included about 70 studies in humans, animals, and cell models. Across these studies, different oils (especially lavender and citrus) and mostly inhalation methods were linked to effects on stress, sleep, mood, pain, alertness, and some brain-related measures, but the studies were varied in methods and outcomes so the results are not one clear answer.

Key facts:

• The review searched studies from 2012 to 2022 and included approximately 70 original studies.
• About 81% of the included studies were done in humans, about 19% in animals, and about 1% in cell cultures (reported from the PubMed subset).
• Lavender essential oil was the most commonly used oil, appearing in about 30.71% of the studies. Citrus species (orange, bergamot, grapefruit, lemon) appeared in about 24.4% of studies.
• Inhalation was the most common way oils were used, reported in about 58.57% of the included studies.
• Reported outcomes across studies included antistress and antianxiety effects, pain relief (analgesic effects), changes in cognition, and changes in autonomic nervous system measures (like heart rate and blood pressure).
• Electroencephalography (EEG) findings often showed lavender had sedative effects, while peppermint and coffee showed stimulating effects on brain activity.
• Massage with lavender and geranium oils was reported to reduce heart rate and blood pressure after the massage in some studies.
• Several essential oils (for example lavender, bergamot, yuzu, Copaifera officinalis resin, Aniba rosaeodora, Juniperus species, and grapefruit) were reported to affect stress-related hormones or markers such as cortisol and salivary chromog
• Some studies reported that certain essential oils can modify neurotransmitter receptor levels and may promote neurite outgrowth, suggesting possible effects on nervous system development or cell signaling.
• The authors described the overall findings as "promising" but the studies used many different methods and measures, so the evidence is varied rather than conclusive.

Abstract

Essential oils are a mixture of natural aromatic volatile oils extracted from plants. The use of essential oils is ancient, and has prevailed in different cultures around the world, such as those of the Egyptians, Greeks, Persians, and Chinese. Today, essential oils are used in traditional and complimentary medicines, aromatherapy, massage therapies, cosmetics, perfumes and food industries. The screening effect of essential oils has been studied worldwide. They demonstrate a range of biological activities, such as antiparasitic, antifungal, antibacterial, antiviral, antioxidant, anti-inflammatory, anticancer, antiaging, and neuroprotective properties. In this scoping review, we provide a 10-year updated comprehensive assessment of volatile oils and their effects on the nervous system. MEDLINE, Scopus, and Google Scholar were systematically and strategically searched for original studies investigating these effects from 2012 to 2022. Approximately seventy studies were selected as included studies. Among these studies, several outcomes were reported, including antistress, antianxiety, analgesic, cognitive, and autonomic effects. Some essential oils showed developmental benefits, with the potential to induce neurite outgrowth. The neurotransmitter receptor level can also be modified by essential oil application. Physiological and pathophysiological outcome measures were reported. For physiological outcomes, arousal, cognitive performance, circadian eating behavior, emotional modulation, consumer acceptance, preferences, and willingness to buy were investigated. For pathophysiological conditions, pain, depression, anxiety, stress, sleep disorder, mental fatigue, agitated behavior, and quality of life were measured. In conclusion, essential oils showed promising effects on the nervous system, which can be further applied to their use in functional foods, drinks, and alternative therapy.

Topics

Essential Oils and Antimicrobial Activity Medicinal Plant Extracts Effects Olfactory and Sensory Function Studies

Categories

Life Sciences Neuroscience Sensory Systems

Tags

Alternative medicine Anxiety Aromatherapy Biology Essential oil Food science Massage Medicine Nutraceutical Pathology Pharmacology Psychiatry Traditional medicine