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13 Peppermint Oil Benefits, Uses & Side Effects

Written by Helen Quach, BS (Biochemistry) | Last updated:
Jonathan Ritter
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology) | Written by Helen Quach, BS (Biochemistry) | Last updated:

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Peppermint Oil

Peppermint oil has some stimulating, physical performance-enhancing, and cognitive-promoting effects. In addition, it is a great digestive aid, helping with IBS, SIBO, dyspepsia, and pain relief. Read this post to learn about the proven health benefits, uses, and side effects of peppermint oil.

What is Peppermint Oil?

Peppermint, also known as Mentha piperita, is a common herb. It is available in many forms – peppermint leaf, peppermint essential oil, peppermint leaf extract, or peppermint leaf water [1].

Peppermint oil has the most uses. It is used in foods, cosmetics, personal hygiene products, and pharmaceutical products. The oil relieves skin irritation and inflammation, reduces pain and nausea, and improves dental hygiene [1].

Constituents

Constituents of peppermint oil include [2, 3]:

  • Menthol
  • Menthone
  • Pulegone
  • Rosmarinic acid
  • Limone
  • Isomenthone
  • Limonene
  • β-myrcene
  • Β-caryophyllene
  • Carvone

Peppermint oil may also cause allergic reactions. It is also mildly toxic when ingested in large amounts. For the most part, peppermint oil is safe for normal use [2].

Peppermint Oil Benefits and Uses

1) Helps Reduce Nausea and Vomiting

Both peppermint and spearmint oils help prevent chemotherapyinduced nausea and vomiting. In a randomized, double-blind clinical trial study, essential oil capsule administration reduced the intensity and occurrence of vomiting after chemotherapy. Patients can use peppermint oil as a safe and effective treatment for nausea [4].

Peppermint oil aromatherapy is another option for relieving nausea. Other aromatherapy uses include those for therapeutic purposes. Molecules are inhaled through the nose, which transforms into chemical signals which have effects on the body [5].

In one study of 18 gynecological surgery patients, peppermint oil aromatherapy helped reduce anesthesia-induced nausea. However, the sample size might be too small to draw a conclusion [6].

In another trial of 60 pregnant women, peppermint oil aromatherapy did not reduce nausea and vomiting. However, it did reduce nausea intensity [7].

Although there is evidence that peppermint essential oil helps treat nausea and vomiting, more studies are needed to come to any definitive conclusions [8].

2) Helps Treat Stomach Disorders

Peppermint oil has historically been used to treat stomach disorders. Menthol, the main constituent of peppermint oil, helps relax smooth muscle in the stomach and intestines [9].

IBS and SIBO

Irritable bowel syndrome (IBS) symptoms include stomach pain, cramping, gas, constipation, and diarrhea.

In a meta-analysis of five different clinical trials, enteric-coated peppermint oil peppermint was mildly effective at reducing IBS symptoms. It was especially effective at reducing flatulence and stomach pain [10].

However, the quality of these studies was variable. This is because there was not a uniform criterion for the diagnosis of IBS [10].

In another study, 57 IBS patients were treated with two enteric-coated capsules twice per day or a placebo. After four weeks, the patients in the peppermint oil group had improved relief from stomach pain [11].

The peppermint oil group had less IBS symptoms compared to the placebo group. The peppermint oil reduced diarrhea, constipation, bloating, and gas [11].

Results concluded that 75% of the patients showed more than a 50% reduction in IBS symptoms compared to 38% of the placebo group. In more than 50% of the treated patients, the beneficial effect of peppermint oil lasted for one month after the therapy. A longer period of therapy may be more beneficial in treating IBS [11].

Up to 80% of IBS cases may be caused by small intestinal bacterial overgrowth. Peppermint oil reduced intestinal hydrogen gas production in patients with bacterial overgrowth. It also reduced IBS symptoms related to abnormal intestinal gas production [11].

Stomach Upset (Dyspepsia)

Non-ulcer dyspepsia is another stomach condition. Its main symptoms include fullness, bloating, and stomach spasms. A combination of enteric-coated peppermint oil and caraway oil reduced dyspepsia symptoms [10].

This may be due to its relaxing effects on the lower esophageal sphincter. The sphincter is the bundle of muscles at the end of the esophagus, where it is connected to the stomach. However, multiple oils were used in the study. Definitive conclusions could not be reached about peppermint’s effectiveness by itself [10].

In a single-blind trial of 12 healthy volunteers, a combination of peppermint and caraway oil helped relax the gallbladder. However, there is no evidence that peppermint is able to treat gallstones [12].

3) Helps Treat Colic

Infantile colic is a hard-to-treat condition in babies and is quite exhausting for their parents. Symptoms include long episodes of crying, irritability, or restlessness. The cause of colic is currently unknown, but stomach disorders may be one contributor to this condition [13].

Researchers studied 30 infants suffering from colic in a study. The infants received formulas with peppermint oil drops for one week [13].

At the end of the study, there was a decrease in the frequency of daily episodes (3.9 to 1.6). The average time of crying minutes per day also decreased (from 192 ±51.6 minutes to 111 ±28 minutes) [13].

However, infantile colic symptoms usually resolve themselves over time. There is a possibility that time improves colic symptoms instead of peppermint oil treatment [13].

4) Stops Muscle Spasms

Menthol is a major constituent of peppermint oil. Menthol peppermint oil relaxes muscles and prevents spasms by blocking calcium channels in muscles [14].

Peppermint oil helps reduce spasms during intestinal procedures. Administration of the oil through enema (injection through the rectum) helps reduce spasms during barium enema and colonoscopies [10].

Peppermint oil is especially useful in stopping spasms in elderly patients during endoscopy [15].

5) May Relieve Headaches

Topical administration of peppermint oil directly onto the skin was effective at reducing patients’ headaches. In one randomized control trial of 41 patients, 10% peppermint oil significantly reduced headache intensity. Peppermint oil was as effective as acetaminophen (an over-the-counter pain reliever, like Tylenol) at relieving the pain [10].

In another trial, 32 healthy subjects used a combination of peppermint oil, eucalyptus oil, and alcohol. They applied it to large areas of the forehead and temples. This combination of oils had a muscle and mentally relaxing effect. However, it did not reduce pain from migraines [16].

On the other hand, the combination of only peppermint oil and alcohol was effective in reducing pain sensitivity in the same subjects [16].

6) Reduces Back and Muscle Pain

Low back pain is a major problem. While nonsteroidal anti-inflammatory drugs (NSAIDs) relieve pain symptoms, they may cause heart problems. Topical herb remedies may be alternative therapies to NSAIDs [17].

A topical application of the combination of wintergreen and peppermint oil may relieve pain. This combination is likely to have fewer side effects than conventional drugs [17].

Stroke patients who experience complete paralysis of half of the body suffer from shoulder pain from the weakening of shoulder muscles. A combination of lavender, rosemary, and peppermint oils aromatherapy helps relieve this shoulder pain [18].

In a randomized, controlled trial of 30 Korean stroke patients, a combination of aromatherapy and acupressure helped relieve shoulder pain. It also improved muscle strength and helped with relaxation. However, there was a small sample size and the possibility of a placebo effect. A more generalized study is needed to support these results [18].

Additionally, in various case studies of Chinese patients of varying ages, an ointment made from peppermint oil relieved joint and muscle pain. “Ping On Ointment” is a combination of peppermint oil, menthol, natural camphor, and other herbal oils. It is a common over-the-counter ointment for stomach and joint pain [19].

Massaging with the topical application of the ointment on the area of muscular and joint pains effectively reduced pain. There was also no recurrence of pain after daily use of the ointment for approximately two weeks [19].

These pain-relieving effects may be due to peppermint oil’s ability to relax and smoothen muscles. However, these are only results from case studies. Additional randomized trials are needed in order to draw specific conclusions [19].

7) Relieves Itching

Severe itching of the skin occurs during pregnancy (pruritus gravidarum). This occurs in 1-8% of pregnant women. However, most pregnant women avoid using synthetic drugs because of their side effects for the baby. The use of peppermint oil is a safe alternative for treating severe itching [20].

In a triple-blind clinical trial, researchers studied the effects of peppermint oil versus placebo on 96 randomly selected pregnant women. The women applied 60 mL of peppermint oil 0.5% in sesame oil on their skin in the affected areas [20].

The peppermint oil was able to reduce itching severity. The difference between the oil and placebo’s effects on itching severity was statistically significant [20].

Severe burn victims also suffer from severe itching (pruritus). In one controlled study, researchers studied the effects of peppermint oil on burn victims. A gel made with peppermint oil, menthol, and methyl salicylate helped relieve skin irritation in the patients [21]

8) Might Enhance Cognitive Performance

Peppermint oil may enhance brain activity. In a study of 144 volunteers, peppermint aroma helped enhance the participant’s scores on memory tests. The peppermint group had better recognition, faster attention speed, and overall better quality of memory in comparison to the control group [22].

However, in a different study of 13 subjects, peppermint tea had no positive effects on memory enhancement. Analysis of brain activity (using EEG) and their performances on a memory task showed no difference between the effects of peppermint tea and tap water [23].

In another study, researchers studied the effects of peppermint odor on the typing performance of 26 participants. There was a significant improvement in typing speed and accuracy when the patients were exposed to peppermint odor versus without the presence of an odor [24].

Therefore, the results of this study suggest that peppermint oil increases arousal and attention. This helped the participants focus on their task and increase performance [24].

However, in another study, peppermint essential oil aromatherapy had no influence on the speed and accuracy of answers in a vigilance task [25].

9) Improves Exercise Performance

Oral administration of peppermint oil significantly improves exercise performances in normal and healthy adults.

In one study, 20 healthy male university students participated in a treadmill test. After the test, they consumed .05 ml peppermint essential oil in 500 ml of mineral water for 10 days. After 10 days of supplementation, they repeated the test [26].

Compared to the results of the first treadmill test, the students performed significantly better after peppermint oil supplementation. They also had a lower heart rate and blood pressure. It took them a long time to become exhausted [26].

In another study, the instant effects of peppermint oil were tested in 30 healthy male university students. Researchers measured grip force, vertical and long jump distance, visual and audio reaction times, blood pressure, heart rate, and breath rate before, five minutes, and one hour after peppermint oil oral administration [27].

After five minutes, compared to the control group, the peppermint group had a significant increase in grip force, vertical jump, and long jump distance. The peppermint group also had a decreased reaction time, heart rate, and breath rate. These changes were still effective after one hour [27].

A possible explanation for these results from both studies includes peppermint oil relaxing the smooth muscles, which helps boost performance. The oil might also reduce blood lactate levels and help the subject feel less tired [26, 27].

10) Reduces Sleepiness

Peppermint oil might be able to reduce sleepiness and invigorate individuals.

In a study, 20 participants were either exposed to peppermint oil or no odors in a darkened room. Scientists measured eye activity, and the participants completed a survey on their perceived sleepiness (using the Stanford Sleepiness Scale) [28].

According to the results of this study, there was a significant decrease in sleepiness in the peppermint group. These results are significant because the control group and peppermint group had no difference in initial sleepiness before odor administration [28].

However, since the study took place in the daytime, there is not yet any connection between peppermint and nighttime sleepiness. Additional studies are required before peppermint oil can be used to delay the onset of sleep [28].

11) Promotes Hair Growth

Medical, natural, or nutritional conditions cause hair loss. Peppermint oil helps induce hair growth. It may also be more effective than FDA-approved hair loss treatments [29].

In a study of male mice, researchers compared the hair growth effects of peppermint oil, saline, jojoba oil, and minoxidil. Topical application of 3% peppermint oil led to faster hair growth than any other solution. It was even more effective than minoxidil, which is an FDA-approved hair growth treatment [29].

After four weeks of topical application, peppermint oil-induced very thick and long hair in mice. These effects may be due to its ability to increase IGF-1 and alkaline phosphatase. The cellular production of IGF-1 supports cell growth and survival, which helps increase hair thickness [29].

12) Is a Natural Antioxidant

Peppermint has good phenolic content and antioxidant activity [30].

The peppermint plant contains naturally occurring phenolics, which have antioxidant properties [31].

One compound from peppermint, rosmarinic acid, significantly reduces UV radiation-induced inflammation. It also helped prevent colon cancer growth in cell culture [31].

However, peppermint oil’s antioxidant activity mostly relies on its chemical composition. Its antioxidant properties depend on the concentration of phenolic compounds. Additionally, the mixture of other components in the oil and extraction techniques also affects its activity [31].

13) Improves Oral Health and Reduces Bad Breath

Peppermint essential oil has antimicrobial activity. In cell culture, it inhibited the growth of four common oral pathogens. This improves oral health [32].

The peppermint plant also has an antibacterial effect. It helped kill and reduce the growth of various bacteria, including E.coli, S. aureus, etc. [30].

Additionally, peppermint oil increases salivation. Dry mouth can result in halitosis (bad breath) [32].

In a clinical trial of 84 students who suffered from bad breath, a peppermint mouth rinse reduced bad breath. It was more effective in comparison to the placebo. After a one-week trial, the prevalence of bad breath was reduced to 24.4% in the students [33].

However, a longer clinical trial is suggested for more conclusive results [33].

Side Effects & Precautions

Common side effects include [10, 1]:

  • Allergic reactions
  • Dermatitis
  • Nausea and vomiting
  • Heartburn
  • Blurred vision
  • Tongue spasms
  • Breathing problems
  • Acid reflux and heartburn; if the upper intestinal tract is exposed to peppermint oil, it relaxes the lower esophageal sphincter [34]

Peppermint oil can be toxic and lethal at excessive doses. Large doses are associated with inflammation of the kidneys and kidney failure. There is no specific antidote for peppermint oil [10, 35].

Peppermint oil contains pulegone, a neurotoxic agent. This means that it may harm nerve tissue. Pulegone is also toxic to the liver. Pulegone’s concentration in peppermint oil is required to be kept at 1% or lower [35].

The oil may increase the volume of secretion of bile and solids from the liver. Patients with gallstones and gallbladder inflammation should not use peppermint oil. Additionally, the use of oil can worsen a hernia and acid reflux symptoms [10].

Peppermint oil interferes with cytochrome P450 enzyme activity. This means that it stops the body from breaking down certain drugs. This can cause drug toxicity and harm the body. However, this effect has not yet occurred in humans [36, 37].

Peppermint may decrease testosterone levels. It also increases follicle-stimulating and luteinizing hormone levels [38].

Infants, children, or pregnant women should not use peppermint oil [10].

Additionally, menthol increases the transfer of toxins and cancer-causing agents through the esophagus. This can increase smokers’ exposure to cancer-causing agents and nicotine [39].

In tea form, peppermint may inhibit iron absorption [40].

Supplementation

Forms and Dosage

In most IBS trials, the optimal dosage range was 0.2 – 0.4 mL peppermint oil taken three times daily in enteric-coated capsules. Enteric-coated peppermint oil capsules pass through the stomach without dissolving. The capsules then disintegrate in the intestines [10].

Colpermin is an enteric-coated peppermint oil capsule. It contains around 0.2 ml of peppermint oil in each capsule. It gets rid of its enteric coat after 1.07 hours. Colpermin’s peak release of its contents is 5 hours after administration [41, 42].

Mintec is another type of peppermint oil capsule. It is also an enteric-coated capsule. Mintec gets rid of its coat after 30 minutes and its release peak is after 2.8 hours, which is faster than Colpermin [42].

Menthol-β-D-glucuronide is another preparation that contains menthol. However, unlike Colpermin and Mintec, it is not enteric-coated [43].

Peppermint oil is eliminated mainly via the bile [14].

User Reviews

For IBS

  • “I have been dealing with IBS for a long time now. Usually, I never feel any difference when I take products like this but I can really feel a difference with the peppermint oil [44].”
  • “I suffer from IBS and using this product has helped tremendously. My doctor prescribed me an antispasmodic pill to take and I feel like this product works better [45].”
  • “I have bad IBS and peppermint oil capsules and peppermint tea has been the only, and I mean the only thing, that has helped to relieve my cramps, bloating, and explosive diarrhea. It’s not a panacea but certainly worth the investment because it helps, but does not completely alleviate IBS symptoms.”

For Headaches/Nausea

  • “Peppermint oil is a lifesaver! Headaches, mood, sore or tight muscles, etc!.”
  • “I am going through chemotherapy and this is my savior against nausea, stomachache, and hot flashes from side effects of chemo.”
  • “This oil has so many uses and has been most effective in use for pain relief without pharmaceuticals.”

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About the Author

Helen Quach

BS (Biochemistry)

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