Does Thieves Essential Oil Really Work? Science Has a Say.

does thieves essential oil really work science has a say

Even if you’re not familiar with the world of essential oils, you may have heard of the famous Thieves blend being used for supporting a healthy immune system. It was actually the reason I first decided to give essential oils a try (because I honestly thought it was hokey, and frankly did not like scents). So – does Thieves essential oil really work? Sound scientific research is very important to me, so I’m going to share what I’ve found.

The Young Living Thieves blend of essential oils (this is why I primarily use Young Living oils) is made up of Clove, Lemon, Cinnamon Bark, Eucalyptus Radiata, and Rosemary. The legend is that 15th century thieves rubbed these oils on themselves during the plague so as not to contract disease while robbing the dead and dying. There are many essential oil companies out there with their own Thieves-type formulations. I want to emphasize that the studies I cite below are about single oils that may be included in a Thieves blend, NOT about a specific company’s blend.

I worked as a researcher in the first 6 years of my Speech-Language Pathologist career in the area of head and neck cancer. This experience has provided me with expertise in interpreting scientific research. I say this because I believe my credentials say something about my ability as a scientist; I’ve seen many “crunchy moms” be dismissed and scoffed at by the scientific community. Well, it’s possible to be a crunchy mom and a scientist. For reals. (If you really want to know, here’s my list of scientific publications in peer-reviewed academic journals.) Ok, enough bragging. Here are some of the studies I looked at:

Deans & Ritchie (1987) looked at 50 different essential oils and their antibacterial properties against 25 types of bacteria. The 10 most inhibitory and comprehensively inhibitory oils included Cinnamon and Clove.

Fu et al (2007) looked at the antimicrobial activity of Clove and Rosemary alone and in combination. Both on their own had significant effects against 3 Gram-positive bacteria, 3 Gram-negative bacteria, and 2 fungi, and the combination of the two oils together had additive, synergistic, or antagonistic effects against each microorganism.

Kalemba & Kunicka (2003) did a review paper of hundreds of studies documenting essential oils and their antimicrobial properties. They stated that Thyme, Oregano, Mint, Cinnamon, Clove, and Salvia had the strongest antimicrobial properties.

Mayaud et al (2008) looked at 13 essential oils and their effect on 65 bacterial strains with varying sensitivity to antibiotics. Their conclusion was that Cinnamon Bark had the highest antimicrobial activity, especially against resistant strains.

Warnke et al (2009) looked at the effect of several essential oils (Eucalyptus, Tea Tree, Thyme white, Lavender, Lemon, Lemongrass, Cinnamon, Grapefruit, Clove Bud, Sandalwood, Peppermint, Kunzea, and Sage) on antibiotic-resistant strains of bacteria (people get infected often through hospital stays). (I can say for a fact that MRSA which was tested in this study, has been running rampant in our local hospitals for several years.) They found that the strongest oils for inhibiting the bacteria were Thyme white, Lemon, Lemongrass, and Cinnamon. They also found that the other oils also demonstrated considerable efficacy and state that “essential oils represent a cheap and effective antiseptic topical treatment option even for antibiotic-resistant strains as MRSA and antimycotic-resistant Candida species“. (This article comes from a sound peer-reviewed journal I’m familiar with, the Journal of Cranio-Maxillofacial Surgery.) Warnke did another study showing the same results with a focus on Lemongrass, Eucalyptus and Tea Tree oils (2013).

Goni et al (2009) found that vapour generated by a combination of cinnamon and clove essential oils prevented the growth of 4 types of Gram-negative and 4 types of Gram-positive bacteria.

Have you tried any Thieves blends, or DIY your own?

Young Living’s Thieves blend is registered in Canada as a Natural Health Product, shown to help relieve colds and coughs.


  • Deans SG, Ritchie G. Antibacterial properties of plant essential oils. International Journal of Food Microbiology 1987; 5(2): 165–180.
  • Fu Y, Zu Y, Chen L, Shi X, Wang Z, Sun S, Efferth T. Antimicrobial activity of clove and rosemary essential oils alone and in combination. Phytother Res 2007; 21(10): 989-94.
  • Goni P, Lopez P, Sanchez C, Gomez-Lus R, Becerril R, Nerin C. Antimicrobial activity in the vapour phase of a combination of cinnamon and clove essential oils. Food Chemistry 2009; 116(4): 982–989.
  • Kalemba D, Kunicka A. Antibacterial and antifungal properties of essential oils. Curr Med Chem 2003;10(10): 813-29.
  • Mayaud L, Carricajo A, Zhiri A, Aubert G. Comparison of bacteriostatic and bactericidal activity of 13 essential oils against strains with varying sensitivity to antibiotics. Letters in Applied Microbiology 2008; 47(3): 167–173.
  • Warnke PH, Becker ST, Podschun R, Sivanathan S, Springer IN, Russo PAJ, Wiltfang J, Fickenscher H, Sherry E (2009). The The battle against multi-resistant strains: Renaissance of antimicrobial essential oils as a promising force to fight hospital-acquired infections. Journal of Cranio-Maxillofacial Surgery 2009; 37(7): 392-397.
  • Warnke PH, Lott AJS, Sherry E, Wiltfang J, Podschun R. The ongoing battle against multi-resistant strains: In-vitro inhibition of hospital-acquired MRSA, VRE, Pseudomonas, ESBL E. coli and Klebsiella species in the presence of plant-derived antiseptic oils. Journal of Cranio-Maxillofacial Surgery 2013; 41(4): 321–326.


43 Responses

  1. Are the scientific studies based on spraying it in the air, or applying it to surfaces?

  2. Really interesting stuff. I always wonder what is the difference is between the oils and say just squeezing some fresh lemon juice (for example) into a glass of water? Is it just the concentration?

    • The essential oil is definitely WAAAAAY more concentrated. And in the case of lemons, it’s not the juice of the lemons, the oil comes from the rind. Here’s a description from the Young Living site: “Lemon essential oil is cold-pressed from the rinds of lemons. Jean Valnet MD estimated that it takes 3,000 lemons to produce one kilo of oil.”

    • I believe the oil from the rind is much more effective, the juice is not oil and does not contain any oil. I have always put lemon juice in my water. I have never had the results that I have now that I use the lemon oil!

  3. hi I am doing something along the lines of this for my school science fair and I need editors name and where it was published do you know where I can find these answers or do you know them

    • Hi Angela, Are you referring to this article? I wrote this (Judith Lam Tang) and published it on my blog here at juicy green mom. The research articles I talk about in my article are referenced at the bottom of the post. Hope this helps.

  4. I joined Young Living because of Thieves. I swear by the stuff, in a diffuser and I put a couple drops on my tongue when I’m feeling congested. Your post just helps prove it’s not all in my head, or rather the placebo effect.

  5. On TV local news last year there was a report on a middle school student who tested the germ killing ability of bleach vs. Thieves (Young Living) Oil. The oil killed more germs than the bleach.

  6. Last winter my husband was in end stage liver cancer. Due to Bill’s weakened immune system, I diffused thieves essential oil everyday to prevent the spread of airborne illness from all the visitors and hospice workers. We were confined to our home. Everyone had to wash their hands upon entering. I made a foaming hand soap with thieves oil to kill surface germs too.
    Neither of us ever got so much as a sniffle all winter long.

  7. Hi Judith, I would like to specifically ask you your thoughts on boosting your immune system with a “roller” of theives and carrier oil. I also use and love Young living, but have been skeptical that Thieves, applied topically, stimulates your immune system. I really like the study about diffusing… But we have very tall vaulted ceilings and unfortunately I feel that it is a waste most of the time to diffuse anywhere other than my bedroom. After being laid up all last week I’m trying to really stay on top of my immune-boosting… Taking Elder Berry syrup and Echinacea and vitamin C… I would use a thieves roller but I just have not seen any support for its use scientifically. Thanks!

    • Hi Anna, Thanks for your question. I don’t know of any scientific studies that talk about the Thieves blend used topically either. However, I do use it topically on a regular basis. In general my family’s health is better than it used to be, but this could be attributed to a lot of things. Topical application of Thieves with a carrier oil is one of the many things we use in addition to diffusing it.

  8. I’m super confused. The dr. Annie’s at home experiments that you mentioned at the end of this blog shows that thieves had no indications of disinfecting or bacteria killing/resistance. It basically disproves your claim. I love the smell of thieves and use it all the time, but I’m having a hard time coming around to the idea that it works as anything other than a scent.

    • Ahh I found the difference. Dr Annie claims that her experiments show that pure thieves or thieves cleaner works to disinfect. However, either one of them diluted does not. In the case of the cleaner which the bottle says to dilute 1:4 — she said it’s no longer effective.

  9. His own study only tested 3 types of bacteria and stated, “…44% reduction in the S. aureus bioaerosol following 10 min of exposure.” In the United States, sanitizers are agents that destroy 99.999% of bacteria in 30 seconds during the Official Detergent Sanitizer Test (a public health test) and disinfectants are products that destroy all organisms in 10 minutes during the AOAC Use Dilution Test, a test regulated by the EPA to determine the efficiency of disinfectants. As a matter of fact, these studies actually all prove that none of the oils even came close to this level of kill rates, some even after 24 hours!

    Imagine that, there’s actually a protocol already in place for testing sanitizers and disinfectants and not even one of the links you provide even come close to performing studies that are even close to these well-established guidelines. Young Living could easily perform these tests in order to make these claims but they don’t because they don’t even come close! That could be the reason they are not allowed to make these claims and instead rely on people like you to make false claims for them.

    The FDA even sent them a warning letter telling them and the people selling their products who are making these claims to stop. Here is a link to the FDA letter sent to them and several of their “consultants” i.e. salespeople for making false claims.

    Also, here is an article that helps explain in greater detail why this is wrong and asks, “Are you prepared to deal with the fallout if someone becomes seriously ill, or even dies as a result of following your advice? Hint … if you don’t have a license to practice and carry liability insurance, nor have the evidence to back up your medical claims, then you are most definitely not.”

    It’s just sad what people will try to present as evidence when there is money involved. Anyone who actually reads your “supporting evidence” who has a fundamental grasp of the English language can see that they DO NOT support your agenda. I wonder how many people have suffered from infections or possibly could have died following your advice.

    I believe the founder of Young Living (Gary Young) actually named his product correctly when he named it “Thieves”! If anyone is in doubt, please take a look at some of the Thieves product ingredients listed on their website. For instance, their Hand Sanitizer’s main ingredient is “Denatured alcohol” which is the same ingredient in nearly all hand sanitizers. They just add some essential oils so it smells prettier but it’s the alcohol that’s killing the germs so instead of paying $0.99 they charge you $6.58 for a 1 oz. bottle! They have to put something in their product that makes it work because they are not allowed to call it a “sanitizer” unless it does. Here’s the link, just click on the Ingredients tab because there isn’t a direct link to the ingredients or scroll down to the list but don’t stop at Key Ingredients, be sure to go to the actual ingredients list.

    Again, they don’t make these claims about their essential oils because they can’t! That’s why they rely on people like yourself to make these false claims to sell their products! Just ask them and they will tell you they don’t, but if you want to sell products…

    Let your conscience be your guide and may you reap what you sow!

    • Thank you for your comment and links to many resources. I appreciate where you are coming from. My original post was simply a collection of the research I had looked at to find out more about the oils contained in Young Living’s Thieves blend. Studies involving essential oils typically use synthentic oils because oils derived from plants can vary tremendously in their chemical components, thus leading the results to be void because the balance of components cannot be controlled the way they can be with synthetic oils. So – from that perspective, the evidence I present really does not have close relevance to the plant-based oils used in Young Living’s Thieves blend. However, I have also become more informed about the practices regarding testing of chemical components in plant-based essential oils, and Young Living has stringent standards in this regard.

      With regard to being able to make claims about essential oils, regulations in any country are what govern this. In Canada, many of Young Living’s oils and products are now classified as Natural Health Products. “Natural health products (NHPs) are naturally occurring substances that are used to restore or maintain good health. They are often made from plants, but can also be made from animals, microorganisms and marine sources. They come in a wide variety of forms like tablets, capsules, tinctures, solutions, creams, ointments and drops.” A description of what products are now classified as NHPs can be found here:

      In the USA, the FDA regulations are different. The same types of claims cannot be made about the exact same essential oils. However, the FDA has classified some essential oils to be safe for ingestion, whereas in Canada, they are classified as safe for “flavouring”. The letter from the FDA that you refer to is from 2014. A lot has changed since then. Young Living has really cracked down since that warning letter on what is allowable for distributors to say regarding claims – exactly to avoid people making claims that are not regulated by the FDA.

      I do not intend to make false claims in order to make money from these products. I share information from my own digging and research so that people can make informed decisions. That is the whole purpose of my blog. The income I may make from affiliate sales or reviewing products is just enough to keep the blog up and running.

      • I’m so glad to have found this post! Thank you for sharing such valuable information! I wish I had more time to read studies myself… Thank you to Darren for the link, maybe later! A few questions on the above comments-

        Regarding the EPA test results- So Clorox/lysol will kill “all organisms in 10 minutes”…is that for sure a good thing?? There are some we benefit from aren’t there? And I know kids can push patience but…lol. Doesn’t seem friendly?! But in comparison with EO, is it a matter of how quickly they kill versus inhibitory effect? Seems so. Inhibitory effect seems more desirable, right? And what about the long term effects on our immune systems? Seems important research to look at simultaneously, right? I’d be suspicious of crutches that further their need… And I can’t help but wonder if people who get worked up in defense of disinfectants/sanitizers put as much energy towards supporting their immune systems…hopefully!

        Regarding synthetic oils used for the studies due to being consistent versus plant based oils used in YL Thieves- Does this mean the “balance of components” in Thieves can vary tremendously as you say is the case for the plant based oils it is made from? Otherwise why would YL use that qualifier to defend against the test results?

        Sorry if that’s an overload of questions! Not expecting you to have all the answers, but would be very appreciative for your thoughts!

        • I certainly do not have all the answers but I appreciate your questions. The more I learn, the more I learn I don’t know.

          What I can answer is that essential oils produced from plants DO vary tremendously in terms of the “balance” of their components. However, YL only sells oils that have the appropriate balance for their therapeutic uses (at least that’s what I learned when I attended a YL convention a few years ago). I believe this is also necessary for them to maintain their Natural Health Product status in Canada for Thieves blend and other oils.

    • Just a couple of comments regarding the post above. Re: Sanitizer and other efficacy testing. With respect to essential oils, the science is absolutely clear on their proven anti microbial activity. Rather than list out all the research anyone may peruse ttps:// Countless fascinating peer reviewed research reports on this subject. Just came across a new one testing the inhibitory effects of topically applied and vapourized Hinokitiol from (CHAMAECYPARIS OBTUSA) on various gram +/- bacteria. Wonderful stuff! Re: FDA letter. Please note that the FDA does not directly address the validity or lack thereof of any of the therapeutic claims being made. Rather they take issue that the product(s) make drug claims without being a legally registered and approved drug by the FDA. Re: Thieves + crimes against post. This is predominantly an opinion piece rather than fact based article so I’ll just leave it at that. For anyone who truly wishes to learn more about the pharmacology, usage and safety of essential oils I would highly recommend they take a visit to Robert Tisserand’s website. Just google his name. He is a well known, unbiased, internationally respected, veritable walking encyclopedia of EO research. Over 40 years experience in the EO industry. Lastly, with respect to the MLM industry and it’s practices, product claims, etc let me just say this to all involved… no one outside a licensed Doctor / Pharmacologist should be encouraging people to consume pure essential oils. There are simply too many circumstances / variables in which a serious reaction and possibly tragic outcome might occur. Essential oils are concentrated, powerful medicines and should be respected as such.

Verified by ExactMetrics