A recent study looked at the use of aroma therapy while sleeping and its effects on Alzheimer's
patients.
Scents are powerful. The use of air fresheners and scented candles is common. The scent of
lemon is associated with cleanliness, or the scent of fresh baked cookies with a cozy home or memories
of your grandmother, and the scent of a Thanksgiving feast brings back childhood memories of past
celebrations. Not all scents are positive, our body respond strongly to scent as a protective measure (we
gag when we smell spoiled milk or rotten eggs). All of this is the result of our olfactory nerve have a
direct route to our brain. Different stimulation from that nerve releases different neurotransmitters and
hormones into our system and we get things like lavender affecting serotonin, GABA receptors, and
NMDA receptors resulting in decreased anxiety, relieving stress and improving restfulness 1 .
The study followed 43 patients for six months. One group was diffused only water, and the
other group diffused a rotation of 7 different scents for two hours each night. The scents they used in
the study included rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender. After six
months they found that the group that diffused scents each night had 226% better scores on Rey
Auditory Verbal Learning Tests that measures verbal learning and memory, including proactive
interference, retroactive interference, delayed recall, retention, and recognition memory. Participants
saw improved performance on word list recall, and other studies have seen improvement in coverbal
fluency and slowed cognitive decline 2 .
There were some measurable changes in the white matter pathways that seem to mediate
episodic memory, language, socio-emotional processing, and selecting among competing memories
during retrieval. This was similar to previous studies that showed people that actively danced vs
listening to audiobooks had increased effects on the brain 2 .
Because olfactory stimulation does not go through the thalamus, there does not appear to be
any provocation of any consciousness to the scents that might impact dreams, and it does deepen slow-
wave sleep, which is the most restful portion of the sleep cycle- possibly to the magnitude of a sleep
medication 2 . Participants did show on average about 22 more minutes of sleep each night than the
control group.
This study did have a small study population, which makes it hard to generalize to everyone.
Not all participants saw improvement- 5% saw a decline, and almost half stayed the same, however this
was better than the control group, which only saw 5% improvement and the rest stayed the same or
declined after six months.
While many feel aromatherapy is hooky and too far out there to be real, there is a growing body
of scientific evidence that supports aromatherapy and it’s effectiveness. And what harm is there in
giving it a try? The cost is relatively small, and even if you don’t see the desired benefit, at least your
home will smell good, and you might get a little more restful sleep. The scent themselves do not appear
to be the key, it seems that variety is the key as the author referenced other studies where participants
smelled a variety of different scent vials multiple times throughout the day, and the variety of scents
essentially helped train and strengthen the neural pathways versus smelling one scent all the time.
Consider picking up a diffuser and a variety of scents you like and see how you feel! We stock
dōTERRA oils at Uptown Pharmacy and our pharmacists are available to help you with questions
regarding this study, and the use of essential oils for other purposes as well.
1. López V, Nielsen B, Solas M, Ramírez MJ, Jäger AK. Exploring Pharmacological
Mechanisms of Lavender (Lavandula angustifolia) Essential Oil on Central Nervous
System Targets. Front Pharmacol. 2017 May 19;8:280. doi: 10.3389/fphar.2017.00280.
PMID: 28579958; PMCID: PMC5437114.
2. Woo Cynthia C., Miranda Blake, Sathishkumar Mithra, Dehkordi-Vakil Farideh, Yassa
Michael A., Leon Michael. Overnight olfactory enrichment using an odorant diffuser
improves memory and modifies the uncinate fasciculus in older adults. Frontiers in
Neuroscience Volume 17, 2023,