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If you get cold sores, it's nothing to be embarrassed about. The American Academy of Dermatology notes that more than half of Americans carry the virus that causes them. While most clear up within two weeks, you may be able to speed up the process by using peppermint oil for your cold sore.

Of course, while you may have some good results using essential oils for the herpes virus that causes cold sores, it's best to check with your doctor before doing any type of at-home treatment, just to be safe.

What's a Cold Sore?

Cold sores, also called fever blisters, are small, fluid-filled blisters that develop on and around your lips. They're caused by a herpes simplex virus called HSV-1. This isn't the same virus that causes genital herpes (that's HSV-2), but the two are very closely related. Most cold sores heal on their own in two to four weeks after passing through a series of stages that include:

  • Tingling, itching and burning around the lips before blisters actually appear.
  • Blisters that erupt in or around the lips, nose or cheeks after a day or two of tingling and itching.
  • Oozing and crusting. In most cases, the blisters erupt, leaving shallow open sores that leak fluid and then eventually harden and crust over.

Signs and symptoms can vary, but it's important to note that cold sores are contagious, even if you can't see them. The current go-to treatment for cold sores is antiviral medication, which reduces the number of outbreaks and helps active cold sores heal faster, but research has also looked at the effectiveness of using an essential oil for a fever blister, or cold sore, instead. And there are promising results.

Read more: How to Make a Cold Sore Pop Fast

What Is Peppermint Oil?

Peppermint oil is an essential oil, which is defined in an August 2015 issue of the Asian Pacific Journal of Tropical Biomedicine as a highly concentrated substance that's extracted from the flowers, leaves, stalks, fruits and roots of various plants. Each essential oil has different chemical properties that may help various conditions, like headache, indigestion, insomnia and anxiety.

According to a report published in the Journal of Acute Medicine in September 2015, plant compounds classified as phenols, flavonoids, alkaloids, and terpenes show anti-herpetic properties. Substances in some of these essential oils help fight off the herpes virus, preventing active infection. They're found in essential oils in varying amounts, but the main compounds in peppermint essential oil responsible for its antimicrobial properties are:

  • Menthol
  • Menthone
  • Methyl acetate
  • Carveone
  • Neomenthol
  • Limonene

Peppermint Oil for Fever Blisters

One study published in the Indian Journal of Traditional Knowledge in July 2018 looked in detail at a wide range of essential oils. Researchers from the study were able to isolate menthol and menthone as two of the compounds in peppermint oil that may help reduce the viral activity of HSV-1 and help make cold sores better.

An older study that was published in Phytomedicine in 2003 looked at how different concentrations of peppermint oil could positively affect the herpes virus. Researchers found that at a 50 percent concentration, peppermint oil could reduce the antiviral activity of both HSV-1 and HSV-2 by 82 percent and 92 percent, respectively. At higher concentrations, the peppermint oil reduced the activity by 99 percent.

This report also noted that peppermint oil was even able to reduce the viral activity of a strain of HSV-1 that's resistant to acyclovir, an antiviral medication typically used to treat cold sores. This may be especially helpful since HSV-1 is known to develop resistance to antiviral medications, according to a May 2014 report in Phytomedicine.

Other Essential Oils for Herpes

But, peppermint oil isn't the only essential oil for a fever blister. Research shows that using other essential oils, like tea tree oil, for cold sores may be effective too. According to a report that was published in the Journal of Pharmacy and Pharmacology in June 2015, the terpenes in tea tree, thyme and eucalyptus essential oils were shown to reduce the viral activity of HSV-1 by more than 80 percent.

Another older report that was published in Antimicrobial Agents and Chemotherapy in April 2007 looked at thyme, ginger, hyssop, sandalwood and oregano essential oils and found that they were all effective in reducing the viral activity of HSV-1 by as much as 95.9 to 99.9 percent.

It's important to keep in mind, however, that many of these studies (although not all) were performed on herpes viruses that were in a controlled lab environment and not in the human body. That means that, while the results are promising, it's still not totally clear whether the essential oils would act entirely the same way in or on the human body.

How to Use Peppermint Oil

Although essential oils are traditionally used as aromatherapy, which means you get their benefits simply by smelling them, the most effective way to use peppermint oil for a cold sore may be to apply it directly to the affected area. Keep in mind that like all essential oils, peppermint oil is highly concentrated, so you need only a few drops. It's also important to dilute the peppermint oil in a carrier oil before applying it to your skin.

The Tisserand Institute recommends a dilution rate of 4 to 10 percent for specific conditions, like cold sores. This means that, if you have 100 milliliters of a carrier oil, like coconut oil or jojoba oil, you would add 4 to 10 milliliters of peppermint oil to it and mix well before applying.

If you don't properly dilute the peppermint oil, it increases your risk of developing skin irritation, like contact dermatitis, which is the most commonly associated adverse reaction reported in connection to essential oils.

Of course, if you're pregnant or have an underlying health condition, the exact amount you should use may differ from the general guidelines. Always discuss your options with a doctor or another qualified health professional who's familiar with your medical history before trying to treat yourself at home.

The August 2015 report in the Asian Pacific Journal of Tropical Biomedicine also notes that essential oils are found to be more effective when combined with healthy changes in diet and lifestyle. So if you're looking to control your cold sore outbreaks, you might want to take a look at the other things in your life, too.