[toc]Although none are conclusively proven, you have probably heard of the many things this type of honey is being researched for.
Antibacterial activity, wound treatments, acne, allergies, cavities, and the list goes on. Many of them involve topical uses and therefore the sugars (i.e. glucose, fructose, maltose, and sucrose) are believed to be inactive ingredients.
If you want skip the sweetness and stick with the phytonutrients of the plant, then the essential oil may offer an intriguing alternative.
Manuka oil vs. Manuka honey
Both come from the nectar of the Manuka tree, which only grows in New Zealand and Australia. When bees make honey from their flowers, it’s called Manuka honey. The essential oil is made by humans, through the steam distillation of the leaves, branches, and other parts, to capture their volatile organic compounds.
This species of tree, Leptospermum Scoparium, is found native throughout New Zealand. Those growing in the East Cape, which is the easternmost point of the country, are exposed to a more strenuous environment; wet, windy, and frequently changing. Their required hardiness is probably why the leaves in this region tend to have more essential oil content and in turn, are a go-to source.
Only a few brands sell Manuka essential oil and it can be expensive when compared to other more common varieties, like oregano and tea tree oil. The latter is sold in two forms – essential and non-essential – while the difference with Manuka is that it’s only sold as the essential (meaning it’s the volatile, non-stable oils).
Both the Manuka tree (Leptospermum Scoparium) and tea tree (Melaleuca alternifolia) are called “tea trees” generically, however they are distinctly different species. The actual tea tree grows in Australia and the Manuka is native to New Zealand.
The well-known brands like Doterra, Young Living, and Plant Therapy do sell it. USDA certified organic Manuka oil is almost non-existent. Being that it’s such a niche oil, manufacturers rarely bother to source organically.
For same reason, finding where to buy essential Manuka oil of any type is a challenge. We could not find it at a Whole Foods in Los Angeles when we looked. A similar independent grocer in Long Beach sold Simplers Botanicals but not for any other brands. We hear it’s even harder to find for sale in the UK.
Although you probably haven’t heard of them, there are a couple specialty brands that focus just on products made from this tree. For example, there is 100% pure East Cape Manuka oil you can get from Naturals New Zealand on Amazon.
The chemical constituents or compounds inside pure oil of Manuka are:
- 60-70% coming from 35 different sesquiterpenes, with the most concentrated being (-)-trans-calamenene (12.5%), d-cadinene (6.3%), cadina-3,5-diene (6.3%), a-copaene (5.3%), and cadina-1,4-diene (4.7%).
- 22% from triketones, with the three most concentrated being leptospermone, flavesone, and isoleptospermone.
- 5% from monoterpenes like a-pinene.
You’re NOT expected to make sense of that scientific jargon, though we list them because you might recognize some from other essential oils. For example, a-pinene is a major active ingredient in frankincense oil, clove oil, and eucalyptus oil.
Though some of the compounds are believed to be unique to Manuka. They’re not even found in other species of the region, like tea tree, which contrary to what some believe, has a much different chemical profile. (1) (2)
Very little research exists on the isolated essential oil. The majority is on Manuka honey (which does contain small amounts of the EO). For that reason, when it’s believed to be relevant, some of what we are about to review involves studies specific to the honey.
The UMF stands for Unique Manuka Factor and it’ measures how much dihydroxyacetone (DHA), methylglyoxal (MGO), and other markers can be detected inside the honey (e.g. UMF 10+, 20).
Please note that this DHA is totally unrelated to omega 3 DHA.
It is true that dihydroxyacetone (DHA) and methylglyoxal (MGO) are created by the sugars in the honey and for that reason, they won’t be in the oil. (3)
Even though the methylglyoxal is believed to be responsible for antibacterial activity of the honey, the essential oil demonstrates antibacterial effects too, which means other compounds in the plant offer this potential.
Manuka oil benefits being studied
1. May have antiviral activity
Manuka honey is a popular remedy for colds, coughs, and sore throats. Whether it truly works or not is unknown, though researchers out of Germany have found that Manuka essential oil…
“…exhibited high levels of virucidal activity against HSV-1 as well against drug-resistant HSV-1 isolates in viral suspension tests.”
HSV-1 is the herpes simplex virus, which causes cold sores and fever blisters. Keep in mind this is only lab research and antiviral activity in humans remains unproven. (4)
On ClinicalTrials.gov, if you search for Manuka and COVID-19 you will see a clinical trial. It’s titled ” Efficacy of Natural Honey Treatment in Patients With Novel Coronavirus” and is conducted by an Egyptian university. This involves the honey, not Manuka oil. The study was last updated in April 2020 and no results have been published. You can view it here.
Anyone claiming that Manuka can treat, prevent, or cure COVID-19 coronavirus is lying. There is no scientific proof of that. Just because a study has been started, that doesn’t mean it helps. Do NOT use manuka for COVID-19 or any other viral infection.
2. Reduces UV skin damage and wrinkles
Another study looked at the oil, this one out of South Korea, and found that when hairless mice had their skin treated with a 10% concentration it…
“…reduced the average length, depth, and % area of wrinkles significantly, and this was correlated with inhibition of loss of collagen fiber content and epidermal hyperplasia.”
There was also inflammation seen.
As you see, the skin benefits were in a dose-dependent manner; the 1% line being the highest (less effective) and the 10% line being the lowest (most effective). Since photoaging is a major cause of skin wrinkling, the researchers suspect that Manuka oil might offer skin care uses for anti-aging when used in added to a face cream or serum. (5)
3. Antibacterial properties
In lab research out of a university in Italy, several essential oils were tested against 14 different strains of Staphylococcus aureus bacteria, which causes staph infections. After oregano oil, the one that exhibited the highest antibacterial activity was Manuka. (7)
Other research has found it to have effects against oral pathogenic bacteria, like Streptococcus mutans and Lactobacillus species. (8)
Those are just a couple of many lab studies published. In humans, there is one study out of India which reported that (9):
“Children using manuka honey showed statistically significant reductions in salivary S. mutans after 10 and 21 days.”
So both the EO and the honey have demonstrated effects against S. mutans.
4. Insect and pest control
The redbay ambrosia beetle (Xyleborus glabratus) is native to Asia but has been present in the Southeast U.S. since 2002. It’s a known carrier of a fungus that kills numerous trees, including the avocado tree.
Research done by the USDA Forest Service found that Manuka oil and phoebe oil were two of the most effective baits for drawing in these beetles so they could be captured and killed, using a poison or some other method since the Manuka itself is non-toxic to them. (6)
Using Manuka honey for mosquito bites is a popular herbal remedy for soothing inflammation and itch. Although not formally tested, certain compounds found in the essential oil might act as a natural mosquito repellent, too.
5. May promote oral health
That study with salivary bacteria in children is not the first time it’s been used for dental hygiene.
As an unproven yet long used remedy, Manuka honey and propolis has been utilized for the management of oral infections. (10)
In a randomized and placebo-controlled feasibility study involving head and neck cancer patients, a gargle solution was made using 2 drops of the essential oils manuka and kanuka (Kunzea ericoides) diluted in water. They wanted to see these added ingredient would relieve mucositis, which is painful inflammation in the mucous membranes (i.e. mouth and throat) that’s a common side effect of chemotherapy and radiation treatments.
Compared to placebo, there appeared to be “a positive effect on the development of radiation induced mucositis.” More research is needed to know for sure. (11)
6. Fights Candida yeast and other fungi
Funded by the Taiwan Society of Microbiology, a group of scientists there tested the essential oils of manuka and the closely related kanuka against four types of fungi which are often associated with hospital-acquired infections:
- Candida albicans
- Candida tropicalis
- Trichosporon mucoides
- Malassezia furfur
Their findings stated (12):
“Multiple analyses of microorganism growth confirmed that both essential oils significantly inhibited four fungi… confirmed by minimum inhibitory concentrations ranging from 0.78% to 3.13%.”
Candida yeast infections are of particular interest, because they are also a difficult to treat disease that manifests itself in the intestines.
Nail fungus hasn’t been tested, though some claim it’s a home remedy that helps. Some home remedy sites go so far as to allege it’s a cure for toenail fungus. They say for it work, you need to remove the infected parts of the nail so the oil can make direct contact with the seat of the fungus. Without clinical data, it’s impossible to evaluate claims like this.
7. Suppresses inflammation
Those same Taiwanese scientists monitored cultured cells for 48 hours as they were exposed to Manuka oil concentrations ranging from 0.1% to 10%. There was no toxicity or adverse side effects seen, as the number of living cells “exceeded 100%” of the starting amount.
After checking for toxicity, they triggered a strong inflammatory response by adding the bacterial endotoxin known as LPS.
When the essential oil was administered along with the endotoxin, the amount of tumor necrosis factor (TNF-a) decreased. TNA-a is a cytokine released by cells as an inflammatory response.
8. Promotes wound healing
Because of or Manuka’s natural antibacterial properties, topical applications of the honey are widely used for the treatment for burns and wounds.
More recent research suggests that it might be helping to repair skin in another way – through the stimulation of human dermal fibroblasts.
In a wound healing model using cultured cells, different types of honeys were tested including this one, buckwheat, and acacia.
The effective treatment of platelet lysate (PL), which is a growth factor, was used for comparison.
Manuka didn’t work as well as the acacia and buckwheat honeys, but it did promote wound closure about 50% better than being untreated (control). (13)
Using Manuka for wounds, burns, and scars is a popular remedy and studies like this lend credence to that possibility.
9. Natural herbicide
The oil glands in the Manuka leaves produce ß-triketones. Scientists now believe it is this compound which is responsible for the plant’s known natural herbicide and pesticide-like properties.
If it can ever be produced and isolated on a large scale, it might work as natural alternative for organic farmers to treat their plants. (14)
10. IBD, IBS, and Crohn’s disease research
In a study, rats were inflicted with a model of irritable bowel disease (IBD). This was accomplished using an acid.
Next, they were split into different treatment groups. These included a control (untreated), sulfasalazine (an ulcerative colitis drug), and Manuka honey in various dosages.
The Manuka offered “significant protection” at dosages of 5 and 10 grams per kilogram of body weight. The inflammation of the colon and other markers of the disease were significantly reduced compared to the control (untreated) group. (15)
Irritable bowel syndrome (IBS), Crohn’s disease, and other digestive diseases are also of interest to researchers. In a guinea pig model, it was found that the essential oil of Manuka relieved muscle spasms of the ileum, which is the third portion of the small intestine. (16)
11. Potential uses for dogs and cats
A common cause of ear infections in dogs is caused by the species Staphylococcus pseudintermedius, which is a type of staph infection. South Korean researchers isolated actual strains from the skin and ears of dogs over a 2 year period.
39 of these strains were methicillin-resistant (antibiotics don’t work for them) and 11 were methicillin-susceptible (antibiotics do work). When all of these strains were treated in the lab using Manuka oil, the results were impressive (18):
“Our results indicated that Manuka oil had excellent activity against all bacterial isolates.”
12. Cancer research
Scientists in Italy wanted to see if the phytochemicals and antioxidants from the honeys of the Manuka and Strawberry tree (Arbutus unedo) might have antiproliferative effects. They tested both against two types of cultured colon cancer cells in the lab:
- human colon adenocarcinoma (HCT-116)
- metastatic colon cancer (LoVo)
Using concentrations of the honeys ranging from 0–20 mg/mL, both inhibited cell proliferation in a dose-dependent manner over 24, 48, and 72 hour periods. (17)
While these results are impressive, it’s no different than frankincense oil and cancer, which may produce intriguing effects in the lab, but that doesn’t mean the same happens inside of animals or humans. This should NOT be considered as a treatment for cancer, as these findings are very preliminary.
Things not studied, but seem promising
Acne on face, back, and chest
Even though there isn’t formal research on using it for pimples, whiteheads, and blackheads, you will find countless reviews online of people using it for this purpose.
How they use this oil for acne is in a diluted form, mixed with a carrier oil or a serum/lotion.
One user said he used a few drops of New Zealand East Cape Manuka oil diluted in jojoba oil. He then spread it on his face at bedtime. He said it left his skin “super smooth” and “nearly all signs of acne are gone.” (19)
At least in theory, there is science to suggest why it may help acne. Being that it has antimicrobial benefits, it may reduce the growth of P. acnes bacteria. That is not a root cause of acne, though it does worsen redness and inflammation of blocked pores, where the bacteria thrive inside.
A few skin care products even market the oil for acne.
There is an interesting product we found for sale that uses Manuka along with the essential oils of tea tree, geranium, basil, red thyme, and others. There’s also vitamin E added. It’s marketed for acne and the directions for how to use it say:
“Apply a few drops onto your fingertips and then apply to affected areas. Use once a day after washing your face.”
To buy or see the reviews, check out Manuka Acne Clear Treatment on Amazon.
Hair growth and dry scalp
In theory at least, the anti-inflammatory effects may help with itchy dandruff and if it really does stimulate the growth of dermal fibroblasts, that might help with the healing of dry and flaky dead skin.
The stories about Manuka oil for hair loss seem more like an old wives’ tale. Since it hasn’t been clinically evaluated, no one can say for certain it does not work. Though on the flip side, there’s no evidence that it does work, nor are there any unrelated findings which would hint it has the potential to stimulate the growth of hair follicles.
Perhaps adding sheen and taming split ends gives the appearance of healthier hair. That’s about as much as one can legitimately claim.
Warts and boils
Common warts of the skin are caused by viruses in the human papillomavirus, or HPV, family. There are more than 100 types of HPV and none have been studied using Manuka oil or honey.
That said, as mentioned above, there are at least a couple lab studies which show that the essential oils of this plant have anti-viral effects against HSV-1 and HSV-2 in cell cultures.
When the viruses were pre-treated with the Manuka oil 60 minutes prior to infecting the host cells, there was a decrease in plaque formation (sign of virus replication) by 99.5% for HSV-1 and 98.9% for HSV-2. To reiterated, those are the viruses which cause herpes and cold sores on the lips. Not warts. (20)
No one knows if this oil can help humans with herpes, let alone whether other types of viruses, like the HPV family which causes warts. This remains an intriguing topic that is worthy of scientific research.
Boils are not the same thing as warts. They’re usually caused by the Staphylococcus (staph) bacteria. Since the oil has demonstrated antimicrobial effects against various strains of staph infections in Petri-dish like experiments, it’s feasible – though unproven – that it might help boils when topically applied.
Eczema and dry skin
Is Manuka honey good for your skin?
The benefits of being anti-inflammatory, anti-bacterial, promoting wound healing, and protecting from UV damage are all traits that suggest topical Manuka oil may improve your skin quality. There is less evidence for the honey helping, except for the support of cuts, burns, and damaged skin.
Even then, the honey has only been evaluated in a couple clinical trials.
One that was published in 2017 used it on 55 patients who underwent cosmetic eyelid surgery (upper blepharoplasty). The surgical incisions of both eyelids were treated with Vaseline 4x daily and in addition, one side was randomized to also get honey.
Healing and scarring on both sides was comparable and it was concluded that “honey may provide subjective benefits early, postoperatively” but not after that. (21)
In an earlier randomized controlled trial, where 108 patients with leg ulcers were treated with the honey or a hydrogel, it was concluded that “Manuka honey was effective in eradicating MRSA from 70% of chronic venous ulcers.” (22)
When it comes to the isolated essential oils being used for skin care, there’s no human data. Only the lab research. As with acne, the anti-inflammatory and moisturizing properties could be good for eczema, though it has not been studied and therefore, also remains an unproven use.
Asthma and allergies
Similar to skin, there’s only circumstantial evidence that it might help with these.
In theory, the anti-inflammatory effects of Manuka oil may alleviate symptoms of allergic rhinitis (hay fever) caused by pollen. Since lab research has found that it reduces TNF-a production (an inflammatory cytokine) in a dose-dependent manner, such effect would be beneficial for excess inflammation cause by allergy attacks.
Asthmatics suffering constriction of the airways may benefit from the relaxation of smooth muscle cells around the lungs. As seen in the guinea pig study, their smooth muscle in the intestinal tract were relaxed when Manuka oil was administered. Anti-inflammatory effects may also lessen the severity of asthma attacks.
Remember this is all theoretical. It should not be used for asthma, allergies, or any other disease. Hopefully research will be done on these topics some day. Since essential oils can irritate the mucous membranes, if it does work, its most likely would be in some sort of diluted form. Otherwise, it may cause the opposite reaction and worsen inflammation and irritation!
Side effects of Manuka oil
When used according to instructions, this essential oil is generally well-tolerated, however the following adverse reactions are possible:
- May cause skin irritation, especially if more than a few drops are used at a time
- Will burn mucous membranes such as the eyes and nasal cavities, which are areas that should be avoided
- If you are allergic to bees you should avoid the honey, while the risk of a separate allergy to the Manuka tree is possible but not common
- Unknown safety during pregnancy and breastfeeding
Verdict
As with other essential oils, there is not enough data to conclusively prove any benefit. For that reason, it should NOT be used for the prevention or treatment of any disease.
The good news is that incorporating it into your skin care regimen appears to be safe with few side effects reported. Adding a few drops to a pump of your favorite face cream is not proven to help wrinkles, pimples, etc. though it probably won’t hurt them either.
Can Manuka oil be taken internally? In small amounts – a serving of a couple drops – some products label it as being safe for internal use. However most are labeled therapeutic grade essential oil, which means they are for external use only. Do not eat or drink a Manuka oil unless the manufacturer’s instructions say it is safe to do so.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.