Aromatherapy: how it works and what it helps with

Aromatherapy uses concentrated plant extracts called essential oils, most commonly through inhalation or diluted application to the skin. The mechanism for its mood effects is plausible: olfactory nerves connect directly to the limbic system, which handles emotion and memory. Evidence supports use for anxiety, mood and sleep. Claims about treating disease, killing infections or detoxification are not supported.

What aromatherapy is

Aromatherapy is the use of essential oils, which are concentrated volatile extracts from plants, for wellbeing purposes. Oils are produced by steam distillation or, for citrus, by cold pressing, and it takes a substantial quantity of plant material to produce a small amount of oil, which is why some are expensive.

In the UK it is most commonly encountered as aromatherapy massage, but also through diffusers, inhalation, bath products and skincare. It is offered in some NHS settings, particularly hospices and some maternity units, as supportive care.

The important framing is that essential oils are pharmacologically active compounds. They are not gentle by virtue of being natural, and the same properties that make them useful also make them capable of causing harm when misused.

How it works

The olfactory route. This is the well-established mechanism and the more interesting one. Scent molecules bind to receptors in the olfactory epithelium at the top of the nasal cavity. Olfactory nerves then project directly to the olfactory bulb and from there to the limbic system, including the amygdala and hippocampus, which handle emotion and memory.

Uniquely among the senses, this pathway bypasses the thalamus, the brain's usual relay station. That anatomical shortcut is why a smell can produce an emotional response or a vivid memory before you have consciously identified it, and it provides a straightforward explanation for why aromatherapy affects mood.

The dermal route. Some absorption through the skin occurs during massage, though the quantities are small at typical dilutions. This is more relevant to safety, particularly in pregnancy, than to efficacy.

The association route. Often underrated. If lavender is what you smell during an hour of being looked after, that scent acquires an association, and the association itself becomes useful. This is a real effect rather than a dismissal.

What the evidence supports

Reasonably supported:

• Anxiety reduction. Lavender in particular has consistent supporting research, including in pre-operative and hospital settings.
• Sleep quality. Commonly reported improvement, with lavender again the most studied.
• Mood. Reasonable evidence for short-term improvement.
• Nausea. Peppermint and ginger have some support, including in post-operative settings.
• Comfort in palliative care. Widely used and valued, primarily for quality of life.

Not supported:

• Treating infections in the body. Some oils have antimicrobial properties in a laboratory dish. That does not translate to treating an infection in a person, and antibiotics exist for good reason.
• Treating disease. No essential oil treats a medical condition.
• Detoxification. Not a mechanism that exists.
• Hormonal regulation or fertility. Frequently claimed, not supported.
• Replacing medication. Never appropriate.

NHS guidance places aromatherapy among complementary therapies to be used alongside conventional care, and advises scepticism about claims to treat serious illness^[1].

Ways it is used

Safety rules that matter

• Always dilute before skin contact. One to three per cent in a carrier oil. Sensitisation from neat application is usually permanent.
• Never ingest. Several oils are toxic when swallowed.
• Keep away from children. Ingestion is a medical emergency; contact NHS 111 or attend A&E.
• Care with pets. Cats in particular cannot metabolise several common oil compounds.
• Pregnancy. A restricted list applies. Clary sage, rosemary and juniper among others are avoided. See the pregnancy massage guide.
• Epilepsy. Rosemary and fennel among others are avoided.
• Photosensitivity. Citrus oils, especially bergamot, increase sun sensitivity.
• Asthma. Strong scents can trigger symptoms in some people.
• Patch test. Particularly with sensitive skin or a history of allergy.
• Store properly. Dark glass, cool, away from light. Oxidised oils are more likely to irritate.

Using oils safely at home

If you want to try it, start simply.

1. Buy a small number of good quality oils. Lavender, sweet orange and peppermint cover a lot of ground.
2. Get a carrier oil. Sweet almond, grapeseed or jojoba, unless you have a nut allergy.
3. Dilute properly. Around 12 drops of essential oil per 30ml of carrier gives roughly two per cent.
4. Patch test. Inside the forearm, wait 24 hours.
5. Ventilate when diffusing. And keep sessions to 30 to 60 minutes rather than running a diffuser all day.
6. Notice what you actually like. Preference matters more than any chart of properties.

Oil-by-oil guidance is in best essential oils for massage, sleep-specific advice in massage for better sleep, and the professional treatment in the aromatherapy massage guide.

For treatment, look for a therapist with a specific aromatherapy qualification and CNHC or IFA registration^[2]. Every therapist listed on Massages Bristol is checked for qualifications and insurance. Browse aromatherapy massage in Bristol or the full directory.

Frequently asked questions

This article is researched by the Massages Bristol editorial team using NHS guidance, professional body standards and published research, and is checked against the practice of the qualified therapists listed in our Bristol directory. It is reviewed and updated when guidance or standard practice changes. It is general information, not medical advice: speak to your GP if you have a health condition that may affect treatment.