What Is Peppermint Oil?

Peppermint (Mentha x piperita) is a perennial herb (meaning it grows year-round). People commonly use it to flavor food and drinks, especially tea.

People sometimes also use peppermint oil and leaves to treat various conditions, from heartburn to tension headaches. Unfortunately, supporting research for these uses is lacking overall.

An exception: There is some evidence that peppermint may reduce symptoms of irritable bowel syndrome (IBS).

This article discusses the health benefits of peppermint and the possible side effects. It also covers appropriate dosages and what to look for when buying it.

Uses of Peppermint

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or doctor. No supplement is intended to treat, cure, or prevent disease. 

People sometimes use peppermint to treat physical discomfort, including IBS, breastfeeding discomfort, abdominal pain, and headache. However, there is limited research to support these claims.

Irritable Bowel Syndrome

Peppermint oil has properties that could be relevant in supporting IBS treatment. These include:

• Antimicrobial (reduces microorganisms, like bacteria or viruses)
• Anti-inflammatory (reduces inflammation)
• Antioxidant (protects cells from damage)
• Immunomodulating (supports the body's immune system)
• Anesthetic (helps reduce the feeling of pain)
• Antispasmodic (helps to relax the smooth muscles in the digestive tract and prevent spasms)

In a 2019 review published in BMC Complementary and Alternative Medicine, researchers evaluated the effect of peppermint oil on IBS. The study reviewed 12 randomized trials spanning five decades and included 835 adults. Researchers found that IBS symptoms and abdominal pain improvement were more significant in the peppermint oil groups than placebo controls.

Abdominal Pain

Another 2017 study in Pediatrics evaluated the effects of herbal medicines, including peppermint, on gastrointestinal disorders in children. The systematic review looked at 14 randomized control trials with 1,927 participants.

Within the review, two studies centered on IBS and peppermint oil. Researchers found no difference between peppermint oil and those who received a placebo.

However, in a study on functional abdominal pain, peppermint oil reduced pain frequency, duration, and severity compared to placebo. In addition, when compared to probiotics, peppermint oil reduced the time and severity of pain.

Breastfeeding Pain

Peppermint's analgesic properties have prompted some studies on its effects when applied topically. Specifically, researchers have looked at how it may impact breastfeeding-related pain.

In an older 2007 study published in the International Breastfeeding Journal, researchers evaluated peppermint water's ability to prevent cracked nipples in 196 Iranian breastfeeding parents who had recently given birth. Participants in the experimental group applied peppermint water to their nipples after every feeding for 14 days. Those in the control group used expressed breastmilk on their nipples after each feeding for 14 days.

Nipple cracks occurred significantly less in the peppermint group compared to the control group—7% to 23%, respectively. In addition, no one in the peppermint group experienced severe cracks, whereas 15% in the control group did.

Another 2014 clinical trial evaluated peppermint's ability to improve nipple cracks in 110 breastfeeding people. Again, researchers divided participants into a peppermint and a control group. The peppermint group applied four drops of menthol essence to their nipples and areolas after each feeding, while the control group applied expressed breastmilk.

On days 10 and 14, researchers evaluated participants' pain intensity and nipple damage. The peppermint group had significantly improved pain and reduced cracking and discharge compared to the control group.

While these studies are promising, more research is needed.

Headaches

The analgesic properties of peppermint have prompted some researchers to evaluate the effects of peppermint on headaches.

In a 2019 study, researchers compared the effects of intranasal lidocaine with peppermint oil on migraines. The double-blind, parallel, randomized controlled trial included 120 Iranian adults with migraines. Researchers divided participants into a lidocaine (anesthetic) group, a peppermint group, and a placebo (control) group.

At the onset of a headache, each group placed two drops of medication into their nose. After 15 minutes, participants evaluated their symptoms and applied a second dose if needed. They then documented their symptoms after 30 minutes. Finally, their physician monitored their symptoms for two months.

For about 40% of participants in the peppermint and lidocaine groups, the therapy reduced the intensity of headaches considerably. On the other hand, few of those in the placebo group responded favorably to treatment.

Other Uses

In addition to the potential health benefits listed above, some people use peppermint to support:

• Relief from endoscopic exams
• Hot flashes
• Dental plaque
• Bad breath
• Pain from shingles
• Stress
• Morning sickness
• Nausea and vomiting

What Are the Side Effects of Peppermint?

Your healthcare provider may recommend you take peppermint for IBS, headaches, or other discomforts. However, consuming an herb like peppermint may have potential side effects. These side effects may be common or severe.

Common Side Effects

Peppermint oil is generally well tolerated, although there are some reports of side effects. These may include:

• Heartburn
• Nausea
• Abdominal pain
• Dry mouth
• Skin rashes and irritation when applied to the skin

Severe Side Effects

Peppermint leaf and oil can also cause allergic reactions, including flushing, headache, and mouth sores.

Peppermint oil appears safe when taken in standard doses and has been used safely in many clinical trials. However, the safety of using large quantities of peppermint leaf or peppermint oil is not known.

Precautions

Researchers know little about peppermint's risks during pregnancy or breastfeeding. Therefore, it is best to avoid it if you are pregnant or breastfeeding.

In addition, people with certain health conditions should use caution and discuss peppermint with a healthcare provider before taking it. These include:

• Kidney disease
• Cholelithiasis (gallstones)
• Cholecystitis (gallbladder inflammation)
• Hiatal hernia (when part of the stomach protrudes through the diaphragm)
• Severe GERD

Avoid using peppermint oil internally or topically in infants and small children.

Dosage: How Much Peppermint Should I Take?

There is no recommended dose of peppermint or peppermint oil. However, studies investigating the herb's effects on different conditions have evaluated various doses.

• For indigestion, participants in one study received a product containing 90 milligrams (mg) of peppermint oil and 50 mg of caraway oil two or three times daily.
• For IBS, most trials have evaluated dosages of 0.2 to 0.4 mL capsules three times a day.
• For children, in one clinical trial, the dosage for kids under 99 pounds was 0.1 mL three times a day.

What If I Take Too Much Peppermint?

Since there is no standard recommended dose, talking to a healthcare provider before taking peppermint is important to ensure you don't take too much. If you experience the side effects noted above, you may have taken too much, or you may be experiencing an allergic reaction. If so, you should seek medical treatment right away.

Interactions

Peppermint may affect how some medications work. These include:

• Tricyclic antidepressants, like amitriptyline
• Immunosuppressants, like cyclosporine
• Antipsychotics, like Haldol (haloperidol)
• Cholesterol-lowering medications, like Zocor (simvastatin)
• Hypertension (high blood pressure) medication, like Plendil (felodipine)

It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss any potential interactions with foods, other supplements, and medications.

How To Store Peppermint

Store peppermint oil in a cool, dry place. Keep peppermint away from direct sunlight. Discard after one year or as indicated on the packaging.

You can store fresh peppermint in the refrigerator. Keep the leaves fresh by wrapping the stems in a damp paper towel and placing them in a plastic bag. Alternately, you could put the stems in a jar of water. Fresh mint stays good for a few days.

Sources of Peppermint and What to Look For

You can eat peppermint fresh, as an herb. Alternately, some people take it as a supplement.

Food Sources of Peppermint

Peppermint is available in grocery stores with the herbs in the produce section. It is also a hardy and easy-to-grow perennial herb thriving in most climates.

People enjoy fresh peppermint in foods and drinks, including:

• Tea
• Salads
• Flavored water
• Mocktails and cocktails
  

Peppermint Supplements

Peppermint oil is available in liquid form and in capsules. Enteric-coated capsules are worth looking for, especially if you have IBS. That's because they protect the oil from being degraded by acid in the stomach.

Check the supplement facts label when buying a peppermint oil product or supplement. It will give you information about what is in the product. Some products contain other ingredients. If you are vegan, vegetarian, or have allergies, read the label carefully to ensure the product does not contain allergens.

Summary

People use peppermint oil to treat various conditions. Unfortunately, most of these aren't supported by research, though it does seem to help relieve irritable bowel syndrome. Side effects may include heartburn or stomach upset.

If you're thinking of using peppermint oil as a supplement, check with a healthcare provider first. They can help you decide whether it would be helpful for your condition. They can also help you determine the dosage you should take.