As I was drinking my lemon water this morning I was inspired to start some research on lemon oil, and I was curious about the benefits I was experiencing by drinking lemon water so often (let me note that I use lemon juice and not lemon oil in my water, although I know lots of people do use the oil), so I thought it was time for the 4th installment in the Just the Facts series! Read on to learn everything you ever wanted to know about lemon oil, including the science that supports (or doesn’t) the claims of its benefits.
Related: The Lemon Water Craze: Explained
Due to the insanely large volume of misinformation available on the properties of essential oils, it is my continuing mission to compile for you a list of facts for each oil. Presented below is my (ever-growing) list of the properties of lemon oil, and the studies that support each claim (references included).
As a young scientist, I know how hard sifting through and understanding
academic articles can be, so I endeavor to remove the jargon for you guys, making this research accessible to everyone. Because this information shouldn’t be limited to people who know words like antiplasmid and ambulatory (or those who have a crazy amount of free time to google each word).
Summary (to save your scrolling finger)
- Origin and Composition
- Neurodegenerative Disorders
- Mosquito Repellent
Origin and Composition of Lemon Oil
Lemon oil (Citrus limon) is derived from the rind of lemons. It can be extracted by either cold pressing or steam distillation, and it’s composition is dependent on the extraction method. Major constituents of cold pressed are: +)-Limonene, B-Pinene, Gamma-Terpinene, a-Terpineol, a-Pinene, Geranial. Major constituents of steam distilled are the same, minus the Geranial (this means it won’t have a strong lemony smell, as this component is the reason lemons smell, well, like lemons). 
Neurodegenerative disorders, such as Alzheimer’s or Parkinson’s, may be able to be managed or prevented by lemon oil. In a study published last year (2014), it was found that lemon oil inhibited enzymes linked to the diseases, as well as acting as an antioxidant. It is commonly proposed that antioxidants are beneficial in the management of neurodegenerative disorders because free radicals have a well-known involvement in the development of these disorders. 
However, much more research needs to be done. This study only covered the possible mechanism behind this hypothesis, testing how lemon oil reacted with rat brains in vitro (meaning with rat brains outside of the rat’s body, as opposed to in vivo which would mean in the living organism). There are no studies where lemon oil is administered and neurodegenerative diseases are seen to diminish or stop getting worse. This work is promising though, and can be considered a first step toward using lemon oil to treat neurodegenerative diseases.
In February of 2014, a group found that inhalation of lemon oil decreased the pain behavior in mice when compared to a control, suggesting that lemon oil decreases the feeling of pain in the nervous system. They propose that the mechanism behind this is that lemon oil is activating dopamine receptors in the brain (dopamine is a hormone secreted naturally by the body that causes feelings of pleasure). Essentially, the brain is tricked into feeling pleasure which reduces the feeling of pain. 
While lemon oil is often cited as improving your sleep, one 1991 study finds that it actually shortened the amount of time mice slept. Lemon oil was administered via inhalation before sleep, along with a pentobarbital (a drug commonly used to induce sleep in these types of studies). 
This finding is echoed by a more recent 2006 study that used rats instead of mice, which finds that lemon oil administered via inhalation significantly reduced pentobarbital sleep time. In contrast, this study found that valerian oil significantly increased pentobarbital sleep time (more on that oil another day!). 
Candida is a yeast that is naturally present on our skin, however it often is the cause of infections ranging from mild to fatal. Lemon oil has been shown to be effective against this yeast, helping keep candida levels healthy or helping get rid of an infection. The authors of the study also mention lemon oil to be antimicrobial in general. 
In a separate study, lemon oil was shown to inhibit growth of Streptococcus mutans (S. mutans), which is a bacteria responsible for tooth decay. Specifically, they found that lemon oil was effective at preventing growth of S. mutans on saliva-coated enamel surfaces, similar to teeth. 
This does not mean, however, that you should start putting lemon oil on your teeth. It is well known that lemon oil or juice can soften the enamel on your teeth, making them susceptible to scratches and other damage. In my opinion, in order to take advantage of this benefit, drinking a glass of lemon water daily should be effective. The juice or oil is diluted enough to not cause too much harm to your enamel while still working to kill the bacteria. Just make sure you don’t brush your teeth for at least an hour after drinking lemon water to give your enamel time to re-harden.
These antimicrobial properties are probably why people recommend lemon oil for dandruff, which can sometimes be caused by a fungus called malassezia.
Lemon oil has been found to act as a mosquito repellent, as well as toxic to the mosquito larva. The authors of the 2012 study propose that the reason for this is the presence of citral, which is a name that includes geranial and neral, compounds that give lemons their lemony scent. 
Lemon oil is commonly used in many commercial repellent products currently, and there are also lots of options for making your own. Just do some research and some trial and error and find what works for you! It’s currently the wrong season here for me to try out any recipes, but let me know if you guys come across something that works well!
- As always, pregnant women, children, and people with sensitive skin should take extra caution when using essential oils and should use higher dilutions. (You can read about dilutions and how to dilute by clicking here)
- Lemon oil contains bergaptene, a component that causes sensitivity to UV light, so anytime oil is applied to the skin extra caution should be taken if that skin will be exposed to sunlight. Without proper care, this sensitivity can lead to harsher sunburns and other sun damage.
- As I mentioned above, lemon oil can soften the enamel of your teeth, so wait at least an hour after drinking lemon water before brushing your teeth to allow your enamel to re-harden and prevent damage.
Also keep in mind that an individual may have an allergic reaction to any oil, so always use caution when using a new oil.
Have you guys heard of other uses for lemon oil that I haven’t touched on? Let me know in the comments below so I can do some research and update this post!
These statements have not been evaluated by the Food and Drug Administration. Essential oils are not intended to diagnose, treat, cure, or prevent any disease.
 Ganiyu Oboh, Tosin A. Olasehinde, Ayokunle O. Ademosun. Essential Oil from Lemon Peels Inhibit Key Enzymes Linked to Neurodegenerative Conditions and Pro-oxidant Induced Lipid Peroxidation. Journal of Oleo Science. (2014). Vol. 63 (2014) No. 4 p. 373-381.
 Hiroshi Ikeda, Syuntaro Takasu and Kazuyuki Murase. Contribution of anterior cingulate cortex and descending pain inhibitory system to analgesic effect of lemon odor in mice. Molecular Pain. (2014). 10:14.
 Toru Tsuchiya, Masahiro Tanida, Shigeharu Uenoyama, Yasuhisa Nakayama, Tatsuya Ozawa. Effects of olfactory stimulation on the sleep time induced by pentobarbital administration in mice. Brain Research Bulletin. (1991). Vol 26, Issue 3. Pages 397–401.
 Teruhisa Komori, Takuya Matsumoto, Eishi Motomura and Takashi Shiroyama. The Sleep-Enhancing Effect of Valerian Inhalation and Sleep-Shortening Effect of Lemon Inhalation. Chem. Senses. (2006). 31: 731–737.
 Białoń M, Krzyśko-Łupicka T, Koszałkowska M, Wieczorek PP. The Influence of Chemical Composition of Commercial Lemon Essential Oils on the Growth of Candida Strains. Mycopathologia. 2014;177(1-2):29-39.
 Ying Liu, Xiangyu Zhang, Yuzhi Wang, Feifei Chen, Zhifen Yu, Li Wang, Shuanglu Chen, Maoding Guo. Effect of citrus lemon oil on growth and adherence of Streptococcus mutans. World Journal of Microbiology and Biotechnology. (2013). Volume 29, Issue 7, pp 1161-1167.
 Athanassios Giatropoulos, Dimitrios P. Papachristos, Athanasios Kimbaris, George Koliopoulos, Moschos G. Polissiou, Nickolaos Emmanouel, Antonios Michaelakis. Evaluation of bioefficacy of three Citrusessential oils against the dengue vector Aedes albopictus (Diptera: Culicidae) in correlation to their components enantiomeric distribution. Parasitology Research. (2012). Volume 111, Issue 6, pp 2253-2263.