12 Essential Oils for Cold Sores Ranked

Essential oils for cold sores

If you’re in the market for a more natural alternative to pharmaceutical treatments, then you’ve probably come across essential oils for cold sores.

Maybe you’ve been disappointed by pharmaceuticals and common over-the-counter cold sore treatments before and are looking for something that works better.

Or maybe you heard your favorite alternative health expert extol the seemingly boundless virtues of essential oils, including for cold sores.

Me? I don’t care what my cold sore treatments are or where they come from.

They could be natural, pharmaceutical, ancient, new, communist, or alien for all I care. As long as they work for healing and/or stopping my cold sores dead in their tracks, I’m a happy camper.

But one must wonder, are essential oils for cold sores effective?

In this article, I took a dive into the world of essential oils to figure out which one is best (if any), and whether or not they are worthy of your time.

What essential oils are good for cold sores?

Name a plant, and there’s probably an essential oil made from it. Which means that there are probably hundreds, if not thousands of different essential oils you can buy. So, I wondered which ones are best for fighting cold sores?

Instead of looking at each and every essential oil there is, I narrowed down my search to the ones that have a history of being used against cold sores. The ones commonly talked about or that cold sore sufferer’s have reported using.

Then, for each essential oil that made the cut, I looked at what the active compound it contains is, what kind of scientific evidence it has to back it up, whether there is anecdotal evidence to back it up, and how it compares to some of the more common cold sore treatments such as Abreva or acyclovir.

Oh, and after that, I put together a nifty table that ranks and compares the main aspects of each.

So without further ado, let’s get cracking.

Tea tree oil

Tea tree oil is perhaps the most commonly used and well known essential oil for cold sores out there, no doubt.

You can buy it basically anywhere and going on reviews and comments, lots of cold sore sufferer’s have used it.

Tea tree oil source and composition

It’s extracted from the leaves of a plant called Melaleuca alternifolia, more commonly known as the Australian tea tree. It has been shown to have antibacterial, antiviral and antifungal activity.

70 to 90 percent of purified tea tree oil is composed of terpinen-4-ol, γ-terpinene and α-terpinene. The other 10 to 30 percent is composed of various other terpenes, but those are the three main ones.

How effective is tea tree oil against cold sores?

One study published in 2001 found that tea tree oil reduced activity of the herpes simplex virus (i.e. the cold sore virus) by up to 98 percent in viral suspension tests.

However, this level of virucidal activity was only achieved when the viral particles were exposed to the tea tree oil, and then used to infect cells with them.

Overall, the general consensus is that tea tree oil is at least somewhat effective against cold sores. Case in point, when a group of scientists performed a small clinical study in actual humans to determine if tea tree oil is effective against cold sores, they found that it reduced the total duration of the outbreak by over 3 days, which is actually better than the results achieved in clinical docosanol studies.

So is tea tree oil effective? It sure seems like it. It has proven to be potent at destroying viral particles, including the herpes virus, which is really all you can ask for from a cold sore treatment.

Black seed oil

Gonna be honest. I had never heard about this oil before researching it for this post. And even the name doesn’t say much about what it is. I mean, how many seeds on the face of this earth are black? Too many to count I bet.

Nevertheless, black seed oil is a thing people use against cold sores outbreaks, so let’s take a look.

Black seed oil source and composition

As it turns out, black seed oil is the oil extracted from the seeds (duh) of a plant called Nigella sativa, more commonly known as the fennel flower.

The plant and seeds themselves apparently have a long history of being used as natural treatments for a wide range of diseases and ailments in many parts of the world, especially in southern Europe and the middle east, and India.

It’s been studied for many different properties, from anti-cancer to liver and kidney protection. Its main active compound is called thymoquinone which makes up almost 50% of its composition. However, it contains a bunch of other compounds that may give it even more healing properties.

Is black seed oil effective against cold sores?

Black seed oil has been shown to have anti-viral properties. For instance, one study found that black seed oil reduced the viral load of humans infected with the hepatitis C virus.

Also, it’s been shown to significantly enhance and support the activity of the immune system in immuno-deficient patients.

However, when it comes to cold sores and HSV-1, there is absolutely nothing to suggest that black seed oil has any benefits whatsoever.

So, given this lack of evidence, I wouldn’t waste my time with black seed oil. There are other essential oils that with proven cold sore fighting properties.

Peppermint oil

Peppermint oil is one essential oil that isn’t quite as well known as tea tree oil or lemon balm oil in terms of a cold sore treatment. However, it is something that is suggested to cold sore sufferers on a regular basis.

Peppermint oil source and composition

Peppermint oil is extracted from, you guessed it, the peppermint plant (Mentha piperita), which is a plant that grows mostly in Europe and north America.

The two main constituents of peppermint oil are menthol, at about 40%, and menthone, at about 25%.

Peppermint oil is used for many purposes and has some scientific evidence to back up its wide range of benefits. It has evidence to support its use for pain, nausea, irritable bowel syndrome, and has even been shown to increase cognitive and athletic performance. It also helps fight bacterial and yeast infections.

Is peppermint oil effective against cold sores?

According to a study published in 2003, peppermint oil has been shown to reduce the activity of the herpes simplex type 1 virus by up to 82% in cultured cells.

The researchers also tested applying peppermint oil at different stages of the viral infection. What they found was that peppermint oil was most effective when the virus was pretreated with it.

This means that, much like tea tree oil, peppermint oil is effective at destroying the viral particles that haven’t infected cells yet, but really doesn’t do much for cells that are already infected.

One interesting tidbit about the peppermint essential oil is that it was found to be effective at killing off particles of a herpes virus strain that was resistant to acyclovir, which makes it more effective than the popular pharmaceutical in some cases.

Lemon balm oil

If tea tree oil is the most well-known essential oil for cold sores, lemon balm oil isn’t far behind. In fact, go to Amazon or do a google search and you’ll see that there are countless cold sore balms and creams that contain lemon balm oil.

So, what’s so special about this essential oil?

Lemon balm oil source and composition

Extracted from the lemon balm plant (Melissa oficinalis), lemon balm oil has demonstrated benefits for indigestion, stress, anxiety, insomnia, has antimicrobial properties and may even have benefits against Alzheimer’s disease.

A study of its composition shows that the main active compound in it is geranial (which is an isomer of citral), which makes up a little under half its weight.

Is lemon balm oil effective against cold sores?

According to a study published in 2008, lemon balm oil reduced the activity of the herpes virus by up to 98%. However, once again this activity was only against free viral particles, not cells which were already infected.

Interestingly, in 1994 a clinical study on human cold sore sufferers showed that a cream containing lemon balm reduces the average time to healing, prevents the spread of infection and reduced the symptoms of pain, itchiness, etc. of cold sores.

Another clinical study of the double-blind, placebo-controlled variety found that applying a balm containing lemon balm extract four times a day reduced symptom severity by almost 20%, as measured on the second day of treatment.

What’s interesting however, is that the main compound in lemon balm oil by weight (geranial or citral) may not be the most active compound in the oil. In fact, one study revealed that most of the anti-herpes activity can be attributed to rosmarinic acid. In fact, this same study put forth that rosmarinic acid may be up to 100 times more potent against the herpes virus than other comparable compounds.

Oregano oil

Not nearly as well known as tea tree oil or lemon balm oil, oregano oil is nonetheless often suggested for fighting cold sores. So, let’s take a look.

Oregano oil source and composition

Because the name makes it so obvious, I’m going to let you guess where oregano oil comes from. I’ll give you a hint: it’s Latin name is Origanum vulgare and it is part of the mint family of plants.

Oregano oil’s main active compound is carvacrol, clocking in at over 60% of its composition by weight.

Oregano oil has many reported uses and benefits. It’s an antibacterial, an antifungal, it has antioxidant properties, can help reduce cholesterol and may even have anti-cancer properties.

Is oregano oil effective against cold sores?

While oregano oil does have demonstrated antiviral properties against multiple types of viruses, what about the herpes virus specifically?

One study did find some effectiveness against the herpes virus in cell cultures, but once again, only when the herpes virus was pretreated with the oregano oil.

And another study found that the main compound in oregano oil, carvacrol, inhibited activity of the herpes virus by up to 90%. Again though, this only occurred only when viral particles were pretreated with the compound.

So, there is definitely some effectiveness and you could definitely do worse, but it’s hard to tell just how effective it is against cold sores compared to other, better known essential oils. That being said, oregano oil also contains some amount of rosmarinic acid which, if you recall, is very potent against the herpes virus.

Lavender oil

While it may not be the most popular essential oil for cold sores, lavender oil just may be one of the more popular essential oils overall.

Lavender oil source and composition

Lavender oil is extracted from the flowers of the Lavandula angustifolia plant.

It’s been reported to be a beneficial treatment in a laundry list of situations such as anxiety, depression, acne, gas, cancer, pain, nausea, insomnia and even fall prevention (?). However, most of those claims are not supported by enough evidence to objectively evaluate their effectiveness.

Its main active compounds are linalool and linalyl acetate which together make up almost half of the oil by weight.

Lavender oil and cold sores

While lavender oil has strong evidence supporting its use against bacterial infections, there isn’t much evidence supporting its antiviral properties.

For example, one study found that essential oils containing linalool may have antiviral properties against the coxsackievirus.

However, the closest thing to evidence that lavender oil may be effective against the cold sore virus is a study that found that an essential oil also containing linalool and linalyl acetate inhibits the activity of the type 2 herpes virus.

So in a nutshell, don’t waste your time with lavender oil if you have a cold sore. It may help with inflammation a bit, but that’s it. Besides, there’s more effective essential oils out there.

Neem oil

Here’s one essential oil that’s a little lesser known. Heck, I had never even heard of this essential before.

But despite my ignorance, it turns out that neem oil is used for many things including treating people with lice, fever, heart disease, indigestion, various skin conditions, diabetes, insect repellant and it’s even used anecdotally as a form of birth control in some countries.

Neem oil source and composition

Neem oil is extracted from the seeds of Azadirachta indica, i.e. the neem, which lives mostly on the Indian subcontinent.

It is mostly composed of up to over 50% of oleic acid and of up to one-third of palmitic acid.

Neem oil and cold sores

While neem oil has a lot of anecdotal evidence supporting its use as an antiviral, concrete scientific information is harder to come by.

In one study published in 2010, neem bark extract was found to inhibit attachment and entry of the herpes simplex 1 virus almost completely in cell cultures. Again, this effect is limited to when the viral particles are pre-treated with the neem bark extract.

On the flip side, another study published in 2004 found that neem oil did not demonstrate any antiviral activity against the herpes simplex 1 virus.

So as you can see, figuring out just what exactly is going on between neem oil and the herpes virus is a little difficult. Some say it works, others say it don’t…

Eucalyptus oil

Eucalyptus oil is probably the essential oil with the most instantly recognizable smell out there. Everybody knows it.

But it turns out eucalyptus oil is good for more than giving a distinctive smell to your bathroom, “post-bidnizz”. It’s good for relieving coughing and congestion, it’s used as a wound disinfectant, can ease joint pain, can keep blood sugar in check and can even be used as an insect repellent.

Eucalyptus oil source and composition

Eucalyptus oil is extracted from the leaves of the Eucalyptus globulus tree (also known as the blue gum tree) which grows mainly in Australia.

The main active compound in eucalyptus oil is called 1,8-cineole (also known as eucalyptol), making up approximately 70% of the essential oil.

Eucalyptus oil for cold sores

The antibacterial activity of eucalyptus oil is well documented. But what about its antiviral activity?

Well, it turns out that a lot of research has been done into not only the antiviral activity of eucalyptus oil, but also specifically about its effect on the herpes virus.

For example, one study published in 2001 compared the effects of tea tree oil and eucalyptus oil on the infectivity of the herpes virus. It found that pre-treating the herpes virus with eucalyptus oil reduced the activity of the herpes simplex 1 virus by just under 60%. That’s a decent number, but given the same study found that tea tree oil reduced infectivity by 98%, it’s a wonder why you’d choose eucalyptus oil over tea tree oil.

On the other hand, a study published in 2018 showed that tereticornate A and cypellocarpin C (two compounds found in eucalyptus oil), were each more effective than acyclovir at suppressing the herpes virus. However, I couldn’t find much information on what concentration of each of these compounds eucalyptus oil contains, so I’m guessing it’s pretty low.

Castor oil

Despite its boring name, castor oil may be the coolest of all the essential oils (more on that in a bit).

It’s a remedy as old as time, as it’s been reported to have been used as far back as in ancient Egypt. It’s main uses are that of a laxative, a skin moisturiser, an anti-inflammatory, an anti-fungal, as an acne remedy, and it may help promote wound healing.

Castor oil source and composition

While most essential oils are extracted from leaves, castor oil bucks this trend. Instead, it’s extracted from the beans of Ricinus communis, also known as the castor bean.

Side note: Remember when I said that castor oil was the coolest of essential oils, like 3 seconds ago? Well, castor beans also contain a cute little toxin named ricin, which was used by the infamous Walter White to sneakily murder Lydia in Breaking Bad. And that alone, in my book, makes it cooler than all other essential oils. Then again, maybe I’m just a dork… Alright, back to business.

Its main active compound is called ricinoleic acid, which makes up approximately 90 percent of its weight. It also contains small amounts of oleic acid and linoleic acid, both clocking in at a little under 5 percent.

Castor oil for cold sores

Castor oil has been reported to have significant antibacterial and antifungal properties, but when it comes to the antiviral activity of castor oil, there is almost literally no evidence to go on.

Really, that’s it. No reported antiviral activity and no reported effect against the herpes virus whatsoever.

Frankincense oil

Frankincense oil is another essential oil I knew nothing about. But it turns out it has a long history of use (dating back as far as medieval times) and has reported benefits for arthritis, asthma, acne, digestive issues such as diarrhea and Crohn’s disease, may help fight bad breath and other dental issues, and may even have cancer fighting properties.

Frankincense oil source and composition

Frankincense oil is a little different from most other essential oils. Instead of being extracted from leaves or bark, it is extracted from the resin of the Boswellia carteri tree.

The chemical composition of frankincense essential oil seems to vary a lot depending on the source. However, its main compounds appear to be α-pinene at anywhere between 20 to 40 percent, and limonene clocking in at anywhere between 12 to 20 percent.

Frankincense oil for cold sores

After digging into the research done on frankincense oil as an antiviral, there unfortunately isn’t much to report. Scratch that. I couldn’t find any reported antiviral activity for frankincense oil. Not against the herpes virus, nor against any other virus for that matter. Heck, it doesn’t even seem to be effective against bacterial infections. At best, it has mild anti-inflammatory properties. I say skip it, there are more effective essential oils for cold sores out there.

Licorice oil (anise oil)

Odds are that when you buy a licorice essential oil, what you’re really getting is anise essential oil. It’s claimed to be effective against a laundry list of conditions, from dry mouth and dental plaque all the way to infertility and prostate cancer, but most of those claims seem unsubstantiated. However, there is some evidence suggesting that it may be effective against eczema and heartburn. Interestingly, it’s used a lot to make various licorice flavored liquors, such as Sambuca and Absinthe.

Anise oil source and composition

Anise oil (or licorice oil) is extracted from Pimpinella anisum, which is native to the eastern Mediterranean region and in Southwest Asia. The oil is extracted from the fruit of the anise plant, and the main compound in the oil is called anethole, making up to 90 percent of the essential oil.

Anise oil for cold sores

According to a study from 2011, anise oil reduces the infectivity of free herpes virus particles by up to 99%, which is significant.

However, this same study also showed that when anise oil is applied to cells already infected with the virus, it only killed off approximately 10% of viral particles.

What this indicates is that anise oil is extremely effective at killing off free particles of the herpes virus, but not so much the ones that have already taken hold in healthy cells. Much like most other essential oils listed here.

Lemongrass oil

The only exposure to lemongrass I had ever had before researching its benefits against cold sores was in Thai food. In lemongrass beef, to be precise. It was ok. A little bland, but ok.

But it turns out that lemongrass oil has many health benefits. It’s used as an anti-bacterial and anti-fungal, it has anti-inflammatory and antioxidant properties, and it’s even beneficial against various digestive issues such as nausea, stomach pain and diarrhea. It also makes a pretty decent tea.

Lemongrass oil source and composition

Lemongrass oil is extracted from the Cymbopogon citratus plant which originates mainly from couth-east Asia. Its main components are compounds of the citral family (mainly geranial and neral) as well as myrcene.

Lemongrass oil for cold sores

A team of scientists published a study in 2003 where they pitted 12 essential oils against each other to determine which ones were most effective at destroying the herpes virus. They determined that lemongrass oil was hands down the most effective essential oil at destroying free particles of the herpes virus. In fact, other mainstay essential oils commonly used against cold sores like tea tree oil and peppermint oil didn’t even come close to the effectiveness of lemongrass oil. However, like most other essential oils, it was only effective when the virus was exposed to the oil before cells were infected.

Also, there are a few essential oils that were unfortunately not included in the study (mainly anise oil and lemon balm oil) that I would be curious to see how they stack up against lemongrass oil.

Finally, an interesting study published in 2018 investigated how creating a nano-emulsion of lemongrass oil affected its potency against the herpes virus. They found a massive increase in potency of the nano-emulsified oil when compared to the pure oil itself. Of course, this doesn’t tell us much about the effectiveness of lemongrass oil itself. Instead, it indicates the potential of the nano-emulsification process in the delivery of the essential oil to cells and tissues and presumably, this process could make any other essential oil more bioavailable.

Sooo… which essential is best for cold sores?

Ok. So now that we went down the list of some of the most commonly used essential oils for cold sores, which one should you use? Is one of them more effective than others? Which one?

To help answer this question, I put together a nifty table based on the sources linked to in this article which compares each oil we talked about here. It compares the oils based on the following criteria:

  • Source of the oil
  • Active compounds
  • In vitro effectiveness (represented in IC50, i.e. what concentration reduced infectivity of the herpes virus in cell cultures by 50%, and plaque reduction %, i.e. the total reduction in infectivity at maximum non-cytotoxic concentrations)
  • Mode of action
  • What effect did it have on humans

With the information laid out like this, it’s easier to compare the essential oils against each other. So without further ado…


Essential oil source Main active compounds In vitro IC50 % Plaque reduction
Action Effect in humans
Tea tree oil Melaleuca alternifolia terpinen-4-ol, γ-terpinene and α-terpinene 0.0009 98.20% Virucidal 3.5 day outbreak reduction
Black seed oil Nigella sativa thymoquinone No data No data No data No data
Peppermint oil Mentha piperita menthol, menthone 0.0020 82% Virucidal No data
Lemon balm oil Melissa oficinalis geranial 0.0004 98.80% Virucidal Reduced symptoms by 20%
Oregano oil Origanum vulgare carvacrol 0.0100 90% Virucidal No data
Lavender oil Lavandula angustifolia linalool, linalyl acetate No data No data No data No data
Neem oil Azadirachta indica oleic acid, palmitic acid No data No data No data No data
Eucalyptus oil Eucalyptus globulus eucalyptol 0.0090 57.90% Virucidal No data
Castor oil Ricinus communis ricinoleic acid No data No data No data No data
Frankincense oil Boswellia carteri α-pinene, limonene No data No data No data No data
Licorice oil Pimpinella anisum anethole 0.0001 99.00% Virucidal No data
Lemongrass oil Cymbopogon citratus geranial, neral 0.0050 99.00% Virucidal No data

Please note that the values indicated here are from the studies linked to in each respective section of this page.

Are essential oils for cold sores more effective than Abreva or acyclovir?

Comparing essential oils for cold sores against more common treatments like Abreva or acyclovir turned out to be a little tricky for a few reasons.

First, there isn’t much clinical data in humans to go on in the case of essential oils. Of the ones listed here, only tea tree oil was been tested in humans and the result was an average increased healing time of 3.5 days.

Second, the essential oils for cold sores researched here all have a different mechanism of action then either Abreva or acyclovir. Essential oils are generally virucidal, Abreva blocks cell attachment, and acyclovir interferes with the intracellular replication of the herpes virus. So even if we could compare the average healing time in humans, it’s not exactly an apples to oranges comparison.

That being said, an Abreva clinical trial published in 2001 found an increase in healing speed of 18 hours, on average . Acyclovir on the other hand showed an average increase of healing time of a little over half a day in 2 separate clinical trials. Contrast that with tea tree oil which was resulted was an average increased healing time of 3.5 days.

But don’t take this for money in the bank. Different studies use different methods and parameters and the mechanisms of action of these compounds will make them more or less effective depending on the stage of a cold sore outbreak they are used at.


Unfortunately, there isn’t much data to go on when it comes to clinical trials made on humans with essential oils for cold sores, which would be the mots revealing form of data. However, based on the rest of the data I’ve found and if you’re looking for an effective essential oil for cold sores, I’d say you can’t go wrong with either tea tree oil, lemon balm oil, licorice oil, or lemongrass oil.

They have demonstrated virucidal activity. So if you do decide to try one of these essential oils on your next cold sore, you can be sure that you will benefit. Heck, they may even be more effective than common pharmaceutical treatments (although I’d like to see better data to draw a definitive conclusion).

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Chris "the Cold Sore Killer" Mueller