Spearmint (Mentha spicata, Mentha viridis)
Natural Standard Bottom Line Monograph, Copyright © 2013 (www.naturalstandard.com). Commercial distribution prohibited. This monograph is intended for informational purposes only, and should not be interpreted as specific medical advice. You should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.
While some complementary and alternative techniques have been studied scientifically, high-quality data regarding safety, effectiveness, and mechanism of action are limited or controversial for most therapies. Whenever possible, it is recommended that practitioners be licensed by a recognized professional organization that adheres to clearly published standards. In addition, before starting a new technique or engaging a practitioner, it is recommended that patients speak with their primary healthcare provider(s). Potential benefits, risks (including financial costs), and alternatives should be carefully considered. The below monograph is designed to provide historical background and an overview of clinically-oriented research, and neither advocates for or against the use of a particular therapy.
Brook mint, bush mint, Clinopodium douglasii, curly leaf mint, English mint, garden mint, green mint, Kentucky colonel spearmint, Indian mint, lamb mint, Lamiaceae (family), menta verde, Mentha picata, Mentha spicata, Menthaspicata L. var. longifolia L., Menthaspicata L. var. spicata, mentha verde, Mentha veridis, Mentha viridis, menthe de Notre Dame, mint, Moroccan green mint, nana mint, our lady's mint, Ovcon®, pudina (India), sage of Bethlehem, Scotch spearmint, spear mint, spire mint, Touareg tea, yerba buena.
Combination product examples: Carmint (Melissa officinalis, Mentha spicata, and Coriandrum sativum); Zahraa (Alcea damascena, Aloysia triphylla, Astragalus cf. amalecitanus, Cercis siliquastrum, Colutea cilicica, Crataegus aronia, Cytisopsis pseudocytisus, Eleagnus angustifolia, Equisetum telmateia, Helichrysum stoechas, Matricaria recutita, Mentha longifolia, Mentha spicata, Micromeria myrtifolia, Paronychia argentea, Phlomis syriaca, Rosa damascena, Salvia fruticosa, Sambucus nigra, Spartium junceum, and Zea mays).
Spearmint (Mentha viridis or Mentha spicata) is a species of mint plant native to Europe and Asia that grows well in nearly all temperate climates. The name is derived from the plant's spear-like pointed leaf tips. It is an invasive species in the Great Lakes region of the United States.
Spearmint is grown for its aromatic and carminative essential oil, called oil of spearmint. Spearmint leaves can be used whole; chopped; dried; dried and ground; frozen; or preserved in salt, sugar, sugar syrup, alcohol, or oil.
Spearmint is an ingredient in several alcoholic drinks, such as the mojito and mint julep. Sweet tea, iced and flavored with spearmint, is a summer tradition in the southern United States. It is used as a flavoring for toothpaste and confectionery, and it is sometimes added to shampoos and soaps. The cultivar Mentha spicata 'Nana', the Nana mint of Morocco, possesses a clear and pungent, but mild, aroma and is an essential ingredient of Touareg tea.
Spearmint-based sprays have been used to control pests, such as weevils, mites, greenhouse whiteflies, sciarid flies, roundworms, and nematodes.
In folk medicine, spearmint has been used for gastrointestinal distress, respiratory problems, stomachache, dandruff, bad breath, and chronic bronchitis. It has also been used as a sedative, abortifacient, and menstruation stimulant (emmenagogue).
Some human research suggests that drinking spearmint tea may help reduce excessive hair growth (called hirsutism) in women with polycystic ovarian syndrome (PCOS). Early evidence suggests that an herbal combination product containing spearmint may help treat irritable bowel syndrome. It is unclear if chewing spearmint-flavored gum improves memory; evidence is mixed.
At this time, high-quality human trials do not support the use of spearmint for any indication. Better-designed clinical trials are needed before conclusions can be made regarding taking this agent for any condition.
Spearmint, spearmint extract, and spearmint oil are listed on the FDA Generally Recognized as Safe (GRAS) list.
Caution is warranted, as spearmint has been found to dose-dependently cause liver and kidney damage. Allergic reactions to spearmint and spearmint oil have been reported.
Although it is commonly recommended that patients with gastrointestinal reflux disease avoid spearmint and peppermint, research in healthy individuals suggests that spearmint may not affect esophageal sphincter function and acid reflux.
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Hair growth (hirsutism)
Excessive hair growth (called hirsutism) is typically a sign of increased androgen levels and is a common symptom of polycystic ovarian syndrome (PCOS). Early evidence suggests that spearmint tea may help reduce hirsutism in women with PCOS. More research is needed to confirm these findings.
Irritable bowel syndrome
The herbal remedy carmint (made from spearmint, lemon balm, and coriander extracts) plus loperamide or psyllium has shown promise as a treatment for irritable bowel syndrome. However, additional studies testing spearmint alone are needed.
It is unclear if chewing spearmint-flavored gum improves memory. Research results are conflicting.
Gastrointestinal reflux disease (acid reflux)
Patients with heartburn or gastrointestinal reflux disease (GERD) are often discouraged from consuming mint-flavored products. It has been suggested that spearmint may impair muscles in the throat. However, in available human research, spearmint had no effect on lower esophageal sphincter function and acid reflux in healthy volunteers.
*Key to grades:A: Strong scientific evidence for this use; B: Good scientific evidence for this use; C: Unclear scientific evidence for this use; D: Fair scientific evidence against this use (it may not work); F: Strong scientific evidence against this use (it likely does not work).
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious and should be evaluated by a qualified health care professional.
Abortifacient, analgesic (pain reliever), antibacterial, antifungal, anti-inflammatory, antimicrobial, antineoplastic (anticancer), antioxidant, antiparasitic, ascaridiasis, bronchitis, common cold, dandruff, dental caries, emmenagogue (menstrual stimulant), fever, food flavoring, gastrointestinal disorders, halitosis, indigestion, insecticide, loss of appetite, nausea and vomiting, nausea and vomiting during pregnancy, relaxation/stress/anxiety, respiratory disorders, sinusitis, stomachache.
The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (18 years and older)
According to secondary sources, to treat a stomachache, it is suggested to drink mint tea, prepared by adding one tablespoon of fresh mint leaves to hot water. To treat dandruff, it is suggested to mix a sprig of spearmint and rosemary in eight ounces of cider vinegar, let it sit for one week, and then apply to the scalp after shampooing.
A high dose of spearmint (500mg) or a flavoring spearmint dose (0.5mg) taken once orally did not show beneficial effects for gastrointestinal reflux disease.
For excessive hair growth (hirsutism), spearmint tea has been taken twice daily for one month, with mixed results. Alternatively, 250mL of spearmint tea has been taken twice daily for five days during the follicular phase of the menstrual cycle with beneficial effects.
Chewing Wrigley's Extra® Thin Ice spearmint-flavored microstrips or Wrigley's Extra® Spearmint sugar-free chewing gum during a learning exercise showed no benefit. However, one study found that chewing or sucking on Wrigley's Extra® Spearmint sugar-free chewing gum during a learning exercise was beneficial.
Children (under 18 years old)
There is no proven safe or effective dose for spearmint in children.
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Avoid in individuals with known allergy/hypersensitivity to spearmint or other members of Lamiaceae (Labiatae) family, such as basil, mint, rosemary, sage, savory, marjoram, oregano, thyme, lavender, and perilla. Carvone, one of the main components of spearmint oil, has been implicated as the main allergen. The sensitizing potential of carvone has been considered low, but it has occasionally caused contact allergy in users of spearmint toothpaste and chewing gum. In a patch test of 541 patients, 15 (2.77%) had positive reactions and 12 had doubtful positive reactions to carvone. The strongest reactions were observed in nine patients who also had Compositae sensitivity. When retesting with l-carvone in the same or lower concentrations, only two out of eight patients had positive reactions.
Although considered rare, allergic contact dermatitis has been reported from spearmint oil and fragrance. In one case, a 64 year-old man developed erythema and blistering on his hands a few hours after picking mint from his garden. Rare cases of contact cheilitis from spearmint oil in toothpaste and chewing gum have been reported.
Side Effects and Warnings
Spearmint appears to be safe in healthy individuals when consumed in amounts normally found in food or beverages. Based on available research, it appears that spearmint is well tolerated in recommended doses up to 500 milligrams daily or taken as a tea twice daily for 30 days. In rare cases, spearmint may cause an allergic response.
Use cautiously in individuals taking iron, as spearmint may inhibit iron absorption.
Use cautiously in individuals with gastrointestinal reflux disease as spearmint may increase the risk of heartburn and regurgitation, although no effect on lower esophageal sphincter function and acid reflux in healthy humans.
Use cautiously in individuals taking CNS depressants, as spearmint may have sedative and antidepressant effects.
Use cautiously in individuals trying to conceive, as spearmint tea may lower testosterone levels, cause damaging effects on testicular tissue, decrease sperm density, and significantly decrease follicle-stimulating hormone (FSH) and luteinizing hormone LH) levels. Use cautiously in individuals using hormonal agents.
Spearmint may cause kidney damage. Use cautiously in individuals with kidney disorders or in those taking drugs that may damage the kidneys.
Spearmint may cause liver damage. Use cautiously in individuals with liver problems or in those who are using drugs that may damage the liver.
Other reported adverse effects include chest pain and decreased libido.
Avoid in individuals with known allergy/hypersensitivity to spearmint or other members of the Lamiaceae (Labiatae) family, such as basil, mint, rosemary, sage, savory, marjoram, oregano, thyme, lavender, and perilla.
Pregnancy and Breastfeeding
Traditionally, spearmint tea is often recommended to relieve nausea and morning sickness in pregnant women. However, there is evidence that spearmint tea caused lipid peroxidation and uterine damage in rats, and spearmint tea was shown to affect hormone levels and testicular tissue in rats.
Information pertaining to spearmint's effects on breastfeeding is currently lacking in the National Institute of Health's Lactation and Toxicology Database (LactMed).
Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.
Interactions with Drugs
Spearmint may interfere with the way the body processes certain drugs that use the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be altered in the blood. Patients using any medications metabolized by cytochrome P450 enzyme system should check the package insert, and speak with qualified healthcare professionals, including pharmacists, about possible interactions.
Spearmint may increase the amount of drowsiness caused by some drugs. Examples include benzodiazepines such as lorazepam (Ativan®) or diazepam (Valium®), barbiturates such as phenobarbital, narcotics such as codeine, some antidepressants, and alcohol. Caution is advised while driving or operating machinery.
Spearmint may increase the risk of liver damage when taken with agents that are broken down by the liver.
Spearmint may increase the risk of kidney damage when taken with agents that are broken down by the kidneys.
Spearmint may also interact with hormonal agents, antibiotics, antifungals, anti-inflammatory agents, cholesterol-lowering agents, anticancer agents, and radioprotective drugs.
Interactions with Herbs and Dietary Supplements
Spearmint may interfere with the way the body processes certain herbs or supplements using the liver's cytochrome P450 enzyme system. As a result, the levels of other herbs or supplements may become too high in the blood. It may also alter the effects that other herbs or supplements possibly have on the P450 system.
Spearmint may increase the amount of drowsiness caused by some herbs or supplements such as sedatives or some antidepressants.
Spearmint may increase the risk of liver damage when taken with herbs or supplements that are broken down by the liver.
Spearmint may increase the risk of kidney damage when taken with herbs or supplements that are broken down by the kidneys.
Spearmint may also interact with antibacterials, antifungals, anti-inflammatory herbs or supplements, cholesterol-lowering herbs or supplements, anticancer herbs or supplements, antioxidants, hormonal herbs or supplements, iron, and vitamin E.
This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.
Akdogan, M, Tamer, MN, Cure, E, et al. Effect of spearmint (Mentha spicata Labiatae) teas on androgen levels in women with hirsutism. Phytother.Res 2007;21(5):444-447. View Abstract
Baker, JR, Bezance, JB, Zellaby, E, et al. Chewing gum can produce context-dependent effects upon memory. Appetite 2004;43(2):207-210. View Abstract
Bonamonte, D, Mundo, L, Daddabbo, M, et al. Allergic contact dermatitis from Mentha spicata (spearmint). Contact Dermatitis 2001;45(5):298. View Abstract
Bulat, R, Fachnie, E, Chauhan, U, et al. Lack of effect of spearmint on lower oesophageal sphincter function and acid reflux in healthy volunteers. Aliment.Pharmacol Ther. 1999;13(6):805-812. View Abstract
Clayton, R and Orton, D. Contact allergy to spearmint oil in a patient with oral lichen planus. Contact Dermatitis 2004;51(5-6):314-315. View Abstract
Grant, P. Spearmint herbal tea has significant anti-androgen effects in polycystic ovarian syndrome. a randomized controlled trial. Phytother Res 7-7-2009. View Abstract
Johnson, AJ and Miles, C. Chewing gum and context-dependent memory: the independent roles of chewing gum and mint flavour. Br J Psychol 2008;99(Pt 2):293-306. View Abstract
Johnson, AJ and Miles, C. Evidence against memorial facilitation and context-dependent memory effects through the chewing of gum. Appetite 2007;48(3):394-396. View Abstract
Larsen, W, Nakayama, H, Fischer, T, et al. Fragrance contact dermatitis: a worldwide multicenter investigation (Part II). Contact Dermatitis 2001;44(6):344-346. View Abstract
Miles, C and Johnson, AJ. Chewing gum and context-dependent memory effects: a re-examination. Appetite 2007;48(2):154-158. View Abstract
Ormerod, AD and Main, RA. Sensitisation to "sensitive teeth" toothpaste. Contact Dermatitis 1985;13(3):192-193. View Abstract
Poon, TS and Freeman, S. Cheilitis caused by contact allergy to anethole in spearmint flavoured toothpaste. Australas J Dermatol 2006;47(4):300-301. View Abstract
Tomson, N, Murdoch, S, and Finch, TM. The dangers of making mint sauce. Contact Dermatitis 2004;51(2):92-93. View Abstract
Torney, LK, Johnson, AJ, and Miles, C. Chewing gum and impasse-induced self-reported stress. Appetite 2009;53(3):414-417. View Abstract
Tucha, O, Mecklinger, L, Maier, K, et al. Chewing gum differentially affects aspects of attention in healthy subjects. Appetite 2004;42(3):327-329. View Abstract
Copyright © 2013 Natural Standard (www.naturalstandard.com)
The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.
March 22, 2017