Peppermint (Mentha piperita) is a hybrid plant that’s been used medicinally for thousands of years, with records stretching back to ancient Greece. The essential oil extracted from its leaves and stems contains primarily menthol and menthone, giving it that characteristic cooling sensation and sharp, clean smell.

Today, peppermint oil appears in everything from toothpaste and chewing gum to massage oils and digestive supplements. But does the research actually support its purported health benefits? I’ve gone through the clinical evidence to separate what’s reasonably well-supported from what’s still speculative.

What the research suggests about peppermint oil

1. Irritable bowel syndrome (IBS) symptom relief

This is probably the best-supported use of peppermint oil. IBS affects somewhere between 5% and 15% of the population and can be genuinely debilitating. The symptoms include abdominal pain, bloating, altered bowel habits (constipation, diarrhoea, or both), and that unpleasant sensation of incomplete evacuation. There’s no cure, which is why people keep looking for anything that might help.

Peppermint oil works as an antispasmodic, relaxing the smooth muscle in the gut wall. The theory is that this reduces the cramping and pain that characterise IBS.

A 2014 meta-analysis looked at nine randomised, placebo-controlled trials involving 726 participants. The pooled data showed that peppermint oil significantly improved global IBS symptoms and reduced abdominal pain compared to placebo [1].

A more recent Cochrane review in 2019 also concluded that peppermint oil was more effective than placebo for improving overall IBS symptoms, though the authors noted the evidence quality was low to moderate [2].

My honest assessment: the effects are real but modest. Peppermint oil isn’t going to cure IBS, but it might take the edge off symptoms for some people. Given the safety profile and low cost, it’s reasonable to try. Enteric-coated capsules work better than regular ones because they bypass the stomach and release in the intestines where they’re actually needed.

If you’re dealing with bladder spasms alongside digestive issues, the antispasmodic effects might theoretically help there too, though I haven’t found clinical trials specifically looking at this.

2. Tension-type headache relief

Tension headaches are the most common type of headache. Unlike migraines, they typically don’t cause nausea or visual disturbances. They’re usually described as a dull, pressing sensation around the forehead or the back of the head, often triggered by stress, poor posture, muscle tension, or eye strain.

A small but interesting study from 1996 tested 10% peppermint oil applied to the forehead and temples on 41 patients with tension headaches. Compared to placebo, the peppermint oil reduced headache intensity, and the effect was comparable to 1,000 mg of paracetamol [3].

The mechanism probably involves the menthol triggering cold receptors in the skin, which may alter pain perception. There might also be some muscle relaxation effect from the cooling sensation.

I wouldn’t throw out your paracetamol based on one small trial, but for people who want to avoid medication or who are looking for something to use alongside painkillers, topical peppermint oil is worth considering. The advantages: it’s cheap, it’s generally well-tolerated, and you can reapply as needed without worrying about the dosing limits that come with oral analgesics.

One caveat: make sure you dilute it properly if using pure essential oil. Applying undiluted peppermint oil to skin can cause irritation.

3. Athletic performance enhancement

This one surprised me when I first read about it. The idea is that peppermint oil might improve respiratory function and exercise capacity.

A 2014 study on 30 male university students found that oral peppermint oil improved grip strength, standing long jump, and vertical jump performance. It also improved some measures of lung function, including forced vital capacity and peak inspiratory and expiratory flow rates [4].

The proposed mechanism is that menthol relaxes bronchial smooth muscle, making breathing easier during exercise.

However, a 2017 study found that peppermint oil didn’t significantly affect maximal oxygen uptake or time to exhaustion during exercise [5].

My take: the evidence is mixed at best. If there’s any real effect, it’s probably small. I wouldn’t recommend peppermint oil to athletes expecting meaningful performance gains. That said, some people find that the sensation of peppermint (whether inhaled or taken orally) makes breathing feel easier, even if objective measures don’t change much. A placebo effect isn’t nothing, especially in sport where psychology matters.

Itching during pregnancy affects roughly 1% to 8% of pregnant women, typically appearing around week 31. It ranges from mildly annoying to severely distressing, sometimes affecting sleep significantly. The causes vary from benign skin stretching to more serious conditions like intrahepatic cholestasis of pregnancy.

A triple-blind randomised trial involving 96 pregnant women with pruritus found that topical peppermint oil reduced the severity of itching [6].

The cooling sensation from menthol likely provides symptomatic relief by stimulating cold receptors and potentially reducing the itch-scratch cycle.

This is preliminary evidence from a single trial, but given how limited the treatment options are for pregnancy-related itching (many medications are contraindicated), peppermint oil offers a relatively safe option to try. Always check with your midwife or obstetrician first though.

Side effects

Peppermint oil is generally safe when used appropriately, but it’s not without potential issues.

When taken orally, the most common side effects include:

Heartburn (the menthol relaxes the lower oesophageal sphincter, which can worsen acid reflux)
Nausea
Allergic reactions, though these are uncommon

When applied topically, you might experience:

Skin irritation or rash
Tingling or burning sensation
Contact dermatitis in sensitive individuals

The oral side effects are more likely with liquid preparations than with enteric-coated capsules, since the capsules are designed to bypass the stomach.

Safety precautions and contraindications

There are specific situations where peppermint oil should be used cautiously or avoided altogether:

1. Infants and young children

Never apply peppermint oil to the face, nose, or chest of babies or young children. Menthol can cause reflex apnoea (breathing stoppage) and laryngospasm in infants. This is a serious risk, not a theoretical concern.

2. Gastro-oesophageal reflux disease (GORD)

If you have GORD or a hiatal hernia, peppermint oil can make symptoms worse. It relaxes the lower oesophageal sphincter, allowing stomach acid to reflux into the oesophagus.

3. Pregnancy and breastfeeding

While topical use for itching appears safe, oral peppermint oil supplements haven’t been adequately studied in pregnancy. Check with your healthcare provider before taking it internally.

4. Liver and kidney disease

People with significant liver or kidney impairment should avoid peppermint oil supplements. The oil is metabolised by the liver and excreted by the kidneys, and there’s not enough data on safety in impaired organ function.

5. Drug interactions with ciclosporin

Peppermint oil may inhibit the enzymes that break down ciclosporin (an immunosuppressant), potentially leading to toxic levels. If you take ciclosporin, avoid peppermint oil.

6. Antacid interaction

If you’re taking enteric-coated peppermint oil capsules, don’t combine them with antacids. The antacids can cause the coating to dissolve prematurely in the stomach, releasing the oil where it’s not wanted and potentially causing heartburn.

7. Cytochrome P450 interactions

Peppermint oil may affect the cytochrome P450 enzyme system, which metabolises many medications. Drugs potentially affected include:

Certain antidepressants (amitriptyline)
Some beta-blockers (propranolol)
NSAIDs (diclofenac, ibuprofen, celecoxib)
Calcium channel blockers (verapamil)
Warfarin
Some statins (lovastatin)

If you’re taking any prescription medications, check with your pharmacist before adding peppermint oil supplements.

Practical recommendations

If you want to try peppermint oil:

For IBS: Use enteric-coated capsules containing 180-200 mg of peppermint oil, taken 2-3 times daily before meals. Enteric coating is important; it prevents the oil from being released in the stomach.

For tension headaches: Apply a 10% peppermint oil solution (diluted in a carrier oil) to the temples and forehead. You can reapply every 15-30 minutes if needed.

For general aromatherapy use: Add a few drops to a diffuser or inhale directly from the bottle. This is generally safe for most adults.

If you’re looking for other natural approaches to gut health, probiotics have a larger evidence base for various digestive conditions.

26 benefits and side effects of curcumin – another natural anti-inflammatory with digestive benefits
3 benefits and side effects of slippery elm bark – traditionally used for digestive issues
4 benefits and side effects of GABA – may help with stress-related digestive symptoms

References

Khanna R, MacDonald JK, Levesque BG. Peppermint oil for the treatment of irritable bowel syndrome: a systematic review and meta-analysis. J Clin Gastroenterol. 2014;48(6):505-512. PubMed
Black CJ, Yuan Y, Selinger CP, et al. Efficacy of soluble fibre, antispasmodic drugs, and gut-brain neuromodulators in irritable bowel syndrome: a systematic review and network meta-analysis. Lancet Gastroenterol Hepatol. 2020;5(2):117-131.
Göbel H, Fresenius J, Heinze A, Dworschak M, Soyka D. Effectiveness of peppermint oil and paracetamol in tension-type headache. Nervenarzt. 1996;67(8):672-681. PubMed
Meamarbashi A. Instant effects of peppermint essential oil on the physiological parameters and exercise performance. Avicenna J Phytomed. 2014;4(1):72-78. PMC
Meamarbashi A, Rajabi A. The effects of peppermint on exercise performance. J Int Soc Sports Nutr. 2013;10(1):15. PubMed
Akhavan Amjadi M, Mojab F, Kamranpour SB. The effect of peppermint oil on symptomatic treatment of pruritus in pregnant women. Iran J Pharm Res. 2012;11(4):1073-1077. PMC
NHS. Peppermint oil. Available at: https://www.nhs.uk/medicines/peppermint-oil/
Mayo Clinic. Peppermint. Available at: https://www.mayoclinic.org/drugs-supplements-peppermint/art-20395820