Simple Lemon essential oil is often overlooked for it's aroma-therapeutic effects, mostly as it's not very exotic. Lemon..."ho-hum, I've got lemons in the 'fridge"...but the idea of Frankincense or Helichrysum sounds like it might do us more good ~ in a mysterious sort of way. But all essential oils have their use, and lemon is at the front of the pack in terms of supporting mental and emotional health.

Lemon essential oil has long been used as a mental stimulant and brightener of the mind. Now scientific investigators have demonstrated some of the mechanisms for this effect. In Japan, a study has shown that lemon oil vapor (as produced by a nebulizing diffuser) has anti-stress effects by modulating both the Serotonin and Dopamine neurotransmitter systems. The conclusion was that lemon oil aroma has both anti-anxiety and anti-depressant effects. Other research performed in Japan years ago showed a significant improvement in mental accuracy for office workers inhaling the aroma.

Also recently published by other Japanese researchers shows that lemon oil actually limits the toxicity of scopolamine ~ a natural plant alkaloid with medicinal effects at low dosages, that shows neurotoxicity at higher dosages. Scoploamine overdose can cause dementia and memory loss. Lemon oil prevented these effects from occuring.

Lemon oil is easy to use, and very safe. It's aroma can be enjoyed from any diffuser, though it would be best to use in a cold-air unit due to the delicate nature of citrus essential oils in general. One can simply just enjoy the aroma as frequently as you like. Here are the studies:

Study: Components of lemon essential oil attenuate dementia induced by scopolamine.

Zhou W, Fukumoto S, Yokogoshi H.Laboratory of Nutritional Biochemistry and G-COE Program in the 21st Century, Graduate School of Nutritional and Environmental Science, University of Shizuoka, Shizuoka, Japan.

The anti-dementia effects of s-limonene and s-perillyl alcohol were observed using the passive avoidance test (PA) and the open field habituation test (OFH). These lemon essential oils showed strong ability to improve memory impaired by scopolamine; however, s-perillyl alcohol relieved the deficit of associative memory in PA only, and did not improve non-associative memory significantly in OFH. Analysis of neurotransmitter concentration in some brain regions on the test day showed that dopamine concentration of the vehicle/scopolamine group was significantly lower than that of the vehicle/vehicle group, but this phenomenon was reversed when s-limonene or s-perillyl alcohol were administered before the injection of scopolamine. Simultaneously, we found that these two lemon essential oil components could inhibit acetylcholinesterase activity in vitro using the Ellman method.

Study: Lemon oil vapor causes an anti-stress effect via modulating the 5-HT and DA activities in mice.

Komiya M, Takeuchi T, Harada E.Graduate School of Veterinary Science, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan.

We examined the anti-stress action of the essential oils of lavender, rose, and lemon using an elevated plus-maze task (EPM), a forced swimming task (FST), and an open field task (OFT) in mice. Lemon oil had the strongest anti-stress effect in all three behavioral tasks. We further investigated a regulatory mechanism of the lemon oil by pre-treatments with agonists or antagonists to benzodiazepine, 5-HT, DA, and adrenaline receptors by the EPM and the FST. The anti-stress effect of lemon oil was significantly blocked by pre-treatment with frumazenil, benzodiazepine receptor antagonist, or apomorphine, a nonselective DA receptor agonist. In contrast, agonists or antagonists to the 5-HT receptor and the alpha-2 adrenaline receptor did not affect the anti-stress effect of lemon oil. Buspirone, DOI, and mianserine blocked the antidepressant-like effect of lemon oil in the FST, but WAY100,635 did not. These findings suggest that the antidepressant-like effect of lemon oil is closely related with the 5-HTnergic pathway, especially via 5-HT(1A) receptor. Moreover, the lemon oil significantly accelerated the metabolic turnover of DA in the hippocampus and of 5-HT in the prefrontal cortex and striatum. These results suggest that lemon oil possesses anxiolytic, antidepressant-like effects via the suppression of DA activity related to enhanced 5-HTnergic neurons.