Ah, basil. Beloved staple herb in pizza sauce and powerful… headache reliever? Basil is much more than a flavorful herb, my friends, and when used in the essential oil form, basil oil is claimed to have numerous benefits (anyone know of an essential oil that isn’t though?). Basil oil is most definitely a potent substance in any case, and this article delves into the REAL benefits of the oil, according to science.
As a young scientist, I know how hard sifting through and understanding academic articles can be, so I endeavor to remove (or explain) 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).
Basil most likely originated in India, and has been cultivated in the middle east since ancient Greek and Roman empires ruled. Currently, it can be found all over the world, and each location-based variety has a different active-constituent profile, which you can read more about here. Sweet basil (Ocimum basilicum) is the most common variety used for making essential oils, and contains linalool and methylchavicol as the major constituents.
When reading research or claims about the benefits of a certain essential oil, it is important to note the variety, because it is the major constituents that are responsible for the effects.
Claims People Make About Basil Oil
- Headache Relief
- Anti fungal
- Insect Repellent
- Anxiety Relief
Let’s go over these claims one-by-one and see what science has to say.
Looking for ways to use basil oil? Download my free basil oil uses cheat sheet from my resource library by clicking the image below! All uses are based on the science in this article.
There’s really only one study I could find that mentioned even any sort of pain relief due to basil oil (if you know of any others feel free to shoot me an email). In this study, basil oil was found to reduce hyperalgesia (super sensitive to pain) in mice who had hyperalgesia artificially induced.
Other than that, though, it seems that people tend to recommend basil oil for stress headaches, and as you can read below, holy basil seems to be a moderate anxiety reducer, so that is probably why basil is said to relieve headaches.
Bottom line: As I mention below in the anti-anxiety section, basil isn’t the best anti-anxiety oil out there, so if you’ve got a stress headache I’d recommend something more widely studied for stress such as lavender oil.
A study in 2014 found that while components of sweet basil oil (Ocimum basilicum) were very effective antiviral agents, the oil itself did not perform as well, and the researchers deemed it impracticable to use the oil as an antiviral therapy. They explain the discrepancy through a lot of boring chemistry I won’t go through, but the short explanation is that they believe the extra components in the whole basil oil inhibit the antiviral activity of the components that are so effective when tested separately (i.e. they are antagonistic rather than synergistic). However, this study only tested one type of virus, a bovine model for hepatitis C.
An older study done in 2005 which tested more viruses, however, came to the same conclusion: that while basil oil does exhibit a little antiviral activity, it’s nothing major enough to be used as a treatment, and the isolated components performed far better against the viruses tested.
Bottom line: Basil oil is slightly antiviral, but not active enough to be recommended as an antiviral therapy.
Last year (2015), a study by El-Soud NH et al found that sweet basil oil (Ocimum basilicum) inhibited growth of the fungus Aspergillus flavus and inhibited production of aflatoxin B1. A. flavus is a fungus commonly found in crops of cereal grains, legumes, and tree nuts. It is pathogenic to humans and other mammals, causing aspergillosis. It is best known for producing the toxin aflatoxin B1, which is a potent carcinogen.
Specifically, this study found that basil oil inhibited growth of the fungus at concentrations above 1000ppm (after crunching the numbers for you, this comes out to be about a 1% dilution), and inhibited the fungus’ production of aflatoxin B1 at concentrations at or above 500ppm (about a 0.3% dilution).
The action of basil oil against this fungus and a few other fungi is supported by this study published just last month (June 2016).
Bottom line: Basil oil is an active anti fungal oil, inhibiting growth in vitro (i.e. in a petri dish).
According to a few different studies, basil oil is a moderately effective antibacterial agent.
In November of 2015, researchers found that a concentration of 17.92uL/mL of basil oil (about 1.8% dilution) was sufficient to inhibit the growth of both Gram positive and Gram negative bacteria, with the Gram positive being a little more susceptible (as expected, because Gram positive bacteria are generally more susceptible to antibiotics). Specifically, the researchers tested Bacillus subtilis, Staphylococcus aureus, Shigella flexneri, and Escherichia coli (i.e. E.coli).
In January of 2016, basil oil was tested against another bacteria strain, Vibrio spp. It was found to have a very low minimum inhibitory concentration of 0.047mg/mL (meaning this is the lowest concentration that inhibited visible bacteria growth).
A third study confirms the efficacy of basil oil against Staphylococcus aureus, reporting a minimum inhibitory concentration of 4ug/mL (note that this is much lower than the amount required to inhibit the Vibrio spp strain in the study above).
However, basil oil doesn’t compare with other oils like tea tree when it comes to multi-drug-resistant Gram negative bacteria (which are becoming all too common in our world of antibacterial soaps and overuse of antibiotics). Basil oil was found to have a minimum inhibitory concentration of more than 4%, compared to as low as 0.12% for tea tree oil. (Tea tree oil is my oil of choice for disinfecting countertops).
Bottom line: Basil oil is an alright antibacterial oil, but it’s not the best one out there by any means.
A study published this year (2016) in the Journal of the American Mosquito Control Association, showed that sweet basil oil is a moderate mosquito irritant and repellant, repelling less than 50% of mosquitos at a concentration of 5%. However, they found that another variety of basil, hairy basil (a.k.a. Ocimum americanum) is a much more effective mosquito repellent, repelling mosquitos better than all other oils studied at a concentration of 0.5%.
Similarly, another study done in August 2015 found that basil oil was 77.4% effective at repelling mosquitos at a concentration of 6.7mg/cm2. While that doesn’t really compare with DEET (100% effective at a concentration of 1.8mg/cm2), it’s still a moderately effective repellent.
When it comes to the poultry red mite though, this study found that basil is less than 30% effective at repelling the insect.
Bottom line: Basil oil is moderately effective against mosquitos, but is not an overarching insect repellent.
In 2007, researchers found that sweet basil oil (Ocimum basilica) significantly reduced an induced inflammation response in rats. The oil was administered by 1:10 tincture (dissolved in alcohol). While it did show a significant effect, however, it was not as effective as diclofenac, a commercially available anti-inflammatory drug.
More recently a 2014 PLoS One article reports that, Ocimum basilica (sweet basil) and Ocimum americanum (American basil) reduce inflammation by 98.2% and 31.6%, respectively.
It is important to note that these two studies measured different compounds when reporting anti-inflammatory activity. The first one measured levels of 4 different components involved in the inflammation response (total leukocyte count, differential leukocyte count, phagocytosis, and nitric oxide synthesis). Leukocytes are inflammatory-response immune cells, the first to arrive at the site of injury to begin the inflammatory response, and the 2007 study found basil oil to be more effective at reducing the leukocyte count than the nitric oxide synthesis.
However, the 2014 PLoS One article only looks at one inflammatory parameter, lipoxygenase, which is an enzyme involved in the inflammatory pathway (i.e. the cascade of different proteins signaling each other to produce inflammation). Therefore the difference in effectiveness reported by these two articles is likely due to the parameters measured.
Bottom line: It’s hard to tell how effective basil oil is at reducing inflammation, however it is obvious that it is effective on some level. I wouldn’t use it as a sole source of anti-inflammatory power, but it could be a nice addition to other anti-inflammatory oils.
In 2005, a Science Direct article reported that Holy basil oil, Ocimum sanctum, caused noise-stressed mice not to produce acetylcholinesterase, which is thought to be involved in the stress response (note this version of the enzyme is only found in mice). This was compared to untreated mice, who showed a significant increase in production of this enzyme under stress.
This study was probably actually a repeat of an earlier study, done in 1997, which found that ethanol extract of Holy basil oil reduced corticosterone levels in the plasma of mice subjected to both acute and chronic (short term and long term) noise stress. While this hormone is of little importance in humans, it is known to be involved in the stress response of many mammals.
In a much more recent study, published in 2016, researchers found that Holy basil oil inhibited the release of cortisol, the stress hormone, in stressed rats.
What science doesn’t say, though, is that sweet basil, Ocimum basilica, is at all effective against stress. In fact, I haven’t been able to find anyone who even bothered to publish a study about it. (However if you know of one, shoot me an email).
Bottom line: Holy basil oil seems to be pretty well established as an effective stress reducer in mice and rats, but I haven’t seen any human trials. If you’re looking for a stress-relieving oil I’d go with something like Lavender, which is better established as a stress-reducer in humans.
I was unable to find any peer-reviewed articles that mentioned decongestant properties of basil oil. (Again, if you know of any, let me know). My guess is that due to it’s mild antiviral and moderate antibacterial and anti-inflammatory properties it tends to reduce the cause of the congestion rather than working like an over the counter decongestant which targets the congestion directly.
Bottom line: possibly effective, depending on the cause of congestion, but no direct evidence from peer-reviewed studies.
While there seems to be very limited information in this area, I was able to dig up two studies that mentioned the stimulant effect.
The first one, done in 2000, mentions in the abstract that a high dose of holy basil oil (Ocimum sanctum) caused in increase in swimming activity of mice, indicating a central nervous system stimulating effect. Since I couldn’t find a link to the full article, based on the information they provide in the abstract it seems like a pretty big leap to make, and I don’t really trust their conclusion.
The second one, done in 2003, seems slightly more believable. Researchers found that human subjects that inhaled basil oil exhibited a heightened skin temperature, which they correlated to a stimulant effect. While not as far of a leap as the first study, without access to the entire article I can’t say for sure how accurate their conclusions are.
Bottom line: Basil oil could have a slight stimulant effect, but there’s not enough trustworthy research to know for sure.
- Basil oil is a ‘hot’ oil, meaning using it undiluted on your skin can cause severe rashes and burning. Use carefully and dilute according to specifications. (You can grab a copy of my essential oil dilution guide from my resource library here.)
- Basil oil should not be used by pregnant women.
- High doses of basil oil may be carcinogenic, so use this oil sparingly.
So thanks for reading guys! If you enjoyed it, or have any questions, let me know in the comments! I’d love to chat. You can read more Just the Facts posts here.