Essential oils are a basic component of aromatherapy, widely used with diffusers or during a massage. But what is it that makes them ‘essential’? Just what can they do for us, and how do we know they are safe?
The word ‘essential’ relates to how the oils capture the ‘essence’ of the plants from which they are derived. Through a variety of methods – most typically steam distillation – roots, bark, seeds, leaves or fruit are turned into an oil. This contains many substances, sometimes hundreds, including volatile organic compounds. These compounds give the oils their smell: they are volatile in the sense that they quickly evaporate in air, transporting the distinctive scent of lavender, say, or peppermint.
Practitioners in the field often take the idea of ‘essence’ further. Farida Irani is founder of Australian brand Subtle Energies, who marry aromatherapy with Ayurvedic principles. She describes essential oils as “the very essence of the plant, the very prana, chi or life force”.
“What an essential oil contains are potent compounds of the plant and that is why we refer to essential oils as concentrated,” says Joanne Bruce, founder and director of Malaysia-based brand Biossentials. “Only a few drops are needed for a therapeutic benefit via inhalation, massage, bath or compress.”
The precise set of substances in those potent compounds though can alter between varieties of the same plant species and even with the location of a given colony of the plant – think of it like the terroir associated with wine.
The industry’s way to get a handle on a given product is to analyse it using gas chromatography mass spectrometry (GC-MS) to establish that it contains only what it is supposed to.
“What is very important when considering using essential oils is that they are genuine (correct botanical species), and are not adulterated, modified or blended,” says Bruce. “Lavender, for instance, has many species but the one that has the calming, healing benefits is known as Lavandula angustifolia. Companies who just put ‘lavender’ or ‘eucalyptus’ on a label without stating the botanical species are not telling the consumer what they are buying. A label should state: 100 per cent Pure & Natural Essential Oil and should have a batch number and use-by date. Consumers should be able to request documents to verify the quality of the oil.”
Once you have a reputable source, you need to understand what these oils can do for you. That is not always straightforward. Although essential oils have been used therapeutically for centuries, and their use in complementary medicine is widespread, especially in Europe, there is relatively little published research on many of them.