Peppermint (Mentha piperita)

What is Peppermint?

Peppermint is a hybrid mint plant that is a cross between watermint and spearmint. It is a perennial herb that is native to Europe and the Middle East, and is now widely cultivated all over the world. The leaves and stems of the peppermint plant are used for their medicinal and culinary purposes.

What are the mechanisms by which it works for medicinal purposes?

Peppermint has several medicinal properties due to the presence of menthol, an active ingredient that provides a cooling and soothing effect on the skin and body. This cooling effect can help soothe muscle and joint pain, improve digestion, and reduce symptoms of headaches, nausea, and indigestion. Peppermint also has antimicrobial properties that help kill bacteria and viruses, and has been used to treat a range of conditions including colds, flu, and skin infections.

What are the active ingredients that are important for its medicinal properties?

The active ingredient in peppermint is menthol, which is responsible for the plant's medicinal properties. Menthol has a cooling and soothing effect on the skin and body, and has antimicrobial properties.

What forms does it come in?

Peppermint is available in several forms, including oil, capsules, tea, and gum. The oil can be used topically, or inhaled as aromatherapy, while the capsules and tea can be ingested orally. Peppermint gum can be chewed to freshen breath and improve oral health.

When was it first used for medicinal purposes?

Peppermint has been used for medicinal purposes for thousands of years. The ancient Egyptians and Greeks used peppermint for digestive problems and headaches, and it has been used in traditional medicine in Europe and Asia for centuries.

What does Peppermint (Mentha piperita) help with?

Peppermint is a mint plant taken as a tea, an oil, or a capsule. People have used it for gut and breathing complaints for thousands of years, in Europe, China, Egypt and India. Most modern research uses peppermint oil in coated capsules, or on the skin.

• Irritable bowel syndrome (IBS): cramping, urgency, unpredictable bowels
  Strong evidence — several clinical trials of enteric-coated peppermint oil capsules. Peppermint oil is one of the most studied plant options for IBS. In several clinical trials, coated capsules lowered belly pain and total IBS symptom scores. People took them for 4 to 8 weeks. Studies of gut muscle show peppermint relaxes that muscle, which may ease spasms.
  Evidence grade A · Traditional tier T2
• Ongoing stomach discomfort with no clear cause (functional dyspepsia)
  Strong evidence — several clinical trials of a peppermint plus caraway oil combination. Functional dyspepsia means repeat stomach discomfort with no structural cause. Several clinical trials tested peppermint oil paired with caraway oil. People reported less pain, less fullness and less pressure. The capsules are enteric-coated so the oil passes the stomach.
  Evidence grade A · Traditional tier T2
• Tension headache
  Good evidence — research comparing diluted peppermint oil with acetaminophen. In research comparing diluted peppermint oil with acetaminophen, the two performed about the same for tension-type headache. The solution went on the temples and forehead. Relief set in within about 15 to 30 minutes.
  Evidence grade B · Traditional tier T2
• Nausea and a queasy, upset stomach
  Early evidence — small human studies of peppermint aroma and oral forms. Both the smell of peppermint oil and oral forms have helped people with nausea in studies. Some people felt less queasy within minutes of breathing in the scent. The studies cover motion sickness, post-surgery queasiness and general upset stomach. They are small.
  Evidence grade C · Traditional tier T2
• Bloating, gas and that over-full feeling after meals
  Early evidence — bloating scored inside the IBS capsule trials; no trial of bloating alone on file. Bloating is one of the symptoms counted in the IBS capsule trials, and those scores fell. No trial on file tested bloating on its own. In gut studies, peppermint relaxed gut muscle, which may let trapped gas move through.
  Evidence grade C · Traditional tier T2
• Stress and mental fatigue during a demanding day
  Early evidence — small human studies of peppermint aroma. In studies of peppermint aroma, people were more alert and reported less mental fatigue. Stress and anxiety ratings dropped modestly during hard tasks. The effects were small, and so were the studies.
  Evidence grade C · Traditional tier T2
• Stuffy nose and sinus congestion
  Long traditional use · not yet tested in trials — no human trial on file; sensory and receptor science only. Menthol is known to switch on cold receptors in the nose, which can make breathing feel easier. That is sensory science, not a trial of peppermint for colds. The library holds no human trial of peppermint steam or menthol chest rubs.
  Evidence grade insufficient · Traditional tier T2
• Sore muscles after exercise or tension
  Long traditional use · not yet tested in trials — no human trial on file; product use and tradition. Peppermint rubs feel cool on the skin, and menthol is known to numb surface pain nerves. That describes how the product feels, not a measured result. No human trial of topical peppermint for soreness is on file here.
  Evidence grade insufficient · Traditional tier T2
• Bad breath
  Long traditional use · not yet tested in trials — lab antibacterial work and long use in dental products; no human trial on file. In lab work, peppermint oil slowed mouth bacteria of the kind linked with odor. Menthol is also a strong scent, and dental products worldwide use it. No human trial of breath odor is on file here.
  Evidence grade insufficient · Traditional tier T2

What Peppermint (Mentha piperita) has not been shown to do

• Plain peppermint oil, without an enteric coating, has not been shown to relieve heartburn; it can relax the valve between the stomach and the gullet and make reflux worse.
• It has not been shown to cure IBS or to change the cause behind it; the trials measured symptom scores over 4 to 8 weeks.
• The headache research on file was in tension-type headache, so it does not show anything about migraine.
• No trial on file shows peppermint shortens a cold or clears a sinus infection.
• No trial on file shows peppermint heals a muscle strain or injury; the topical work is about the cooling feel.
• No human trial on file shows peppermint treats gum or dental problems that cause bad breath.

How to read this:

The grades run from A down to insufficient. A means several human trials agree. B means one good human trial. C means small or mixed human studies. D means the human evidence is weak or clashing. Insufficient means no human trial is on file. This page sets out options and what studies found. It is not medical advice, and it is not a dosing guide.

What can Peppermint (Mentha piperita) help prevent?

• Recurrence of IBS flare-ups with consistent daily use of enteric-coated oil
• Tension headache episodes when used regularly as a preventive topical treatment
• Post-operative nausea when peppermint aromatherapy is used peri-operatively

Which foods are rich in Peppermint?

Peppermint is not commonly found in food, but the leaves can be used fresh or dried to flavor dishes and teas.

What are possible side effects?

Peppermint is generally well tolerated at Possible side effects of peppermint include heartburn, headaches, skin irritation, and allergic reactions. These side effects are generally mild and occur in a small percentage of people.

What’s the recommended daily dose?

The recommended daily dose of peppermint varies depending on the form it is taken in. For peppermint oil, the recommended dose is 0.2 to 0.4 ml, while for peppermint tea, the recommended dose is 2 to 3 cups per day.

How many days does it take to work?

The time it takes for peppermint to work depends on the individual and the condition being treated. For some conditions, such as headaches, relief may be immediate, while for others, such as digestive problems, it may take several days of consistent use to see a difference.

What time of day is best to take it?

Peppermint can be taken at any time of day, although it is best to avoid taking it late in the evening