Botanical name Mentha spicata
Processing Method Steam Distilled
Color/Consistency A thin, clear, colourless to pale yellow liquid.
Aromatic Summary / Note / Strength of Aroma A top note with a medium aroma, it has a characteristic scent that is sweeter than the minty aroma of peppermint.
Blends With Basil, Bergamot, Eucalyptus, Sweet Birch, Jasmine, Lavender and Rosemary.
Spearmint, or spear mint, also known as garden mint, common mint, lamb mint and mackerel mint is a species of mint native to much of Europe and Asia (Middle East, Himalays, China etc.), and naturalized in parts of northern and western Africa, North America and South America, as well as various oceanic islands. Mentha spp. and their hybrids, Spearmint makes one of the better-flavored mint teas. Spearmint flavoring is also used in chewing gum and other products; it has significant economic importance. Spearmint has been widely cultivated since ancient times, and was introduced to the British Isles by the Romans.
John Gerard's Herbal (1597) states that: "It is good against watering eyes and all manner of break outs on the head and sores. It is applied with salt to the biting of mad dogs," and that "They lay it on the stinging of wasps and bees with good success." He also mentions that "the smell rejoice the heart of man", for which cause they used to strew it in chambers and places of recreation, pleasure and repose, where feasts and banquets are made.
The spearmint essential oil is extracted by steam distillation of flowering tops of the spearmint plant, whose scientific name is Mentha spicata. The main components of this oil are alpha-pinene, beta-pinene, carvone, cineole, caryophyllene, linalool, limonene, menthol, and myrcene.
There are no reported dangers of using this essential oil, but as an emmenagogue, it should not be taken by pregnant women.
Quality May be adulterated with added (–)-carvone.
Hazards Skin sensitization (low risk); mucous membrane irritation.
Contraindications None known.
Maximum dermal use level 1.7%
Our safety advice
We recommend a dermal maximum of 1.7%, based on 71.6% (–)-carvone content, and a dermal limit of 1.2%. We recommend a human daily oral maximum dose of 12.5 mg/kg for carvone isomers, which is
effectively not restrictive.
Has GRAS status. The IFRA standard for either isomer of carvone in leave-on products such as body lotions is 1.2%, for skin sensitization. The Council of Europe (1992) has set an ADI of 1 mg/kg for carvone (isomer not specified). This is equivalent to a daily dose of 90–115 mg of spearmint oil (depending on ()-carvone content) for an adult, or approximately three drops.
Adverse skin reactions Undiluted spearmint oil was moderately irritating to rabbits, slightly irritating to guinea pigs and was not irritating to mice or pigs; tested at 4% on 25 volunteers it was neither irritating nor sensitizing. Spearmint oil is nonphototoxic. Spearmint oil, tested at 2% in consecutive dermatitis patients, induced allergic responses in 13 of 1,606 and five of 318 (1.6%) . Of 178 dermatitis patients who were “sensitive to fragrance”, 9 (5.0%) tested positive to 5% spearmint oil. Few cases of spearmint oil sensitization are recorded, suggesting that they are rare. A 64-year-old woman developed allergic
lesions on one knee after applying an infusion made with fresh spearmint leaves for pain relief. She tested positive to 2% spearmint oil and 2% peppermint oil, but not to 1% menthol. There have been several cases of oral lesions linked to spearmint oil. One woman developed a sore mouth accompanied by fissuring of the lips and scaling and edema of the surrounding skin. A number of similar cases were reported by both Anderson & Styles and Francalanci et al. A case of allergic stomatitis to spearmint oil was reported by Clayton and Orton.
Acute toxicity Spearmint oil acute oral LD50 in rats 5 g/kg; acute dermal LD50 in rabbits >5 g/kg; acute dermal LD50 in guinea pigs >2 g/kg.
Carcinogenic/anticarcinogenic potential Mentha spicata oil was strongly mutagenic in fruit flies (Franzios et al 1997). Spearmint oil was not mutagenic in either a CA test or an Ames test . In mouse micronucleus tests, spearmint oil was not genotoxic (Hayashi et al 1988). Spearmint oil showed significant chemopreventive activity against human mouth epidermal carcinoma (KB) and mouse leukemia (P388) cell lines, with respective IC50 values of 65 and 61 mg/mL. The oil was more effective than three of four positive control drugs. Mentha spicata oil was cytotoxic to human prostate cancer cells with an IC50 value of 0.09%, but was not cytotoxic to human lung or breast cancer cells. Spearmint oil residues significantly induced glutathione S-transferase activity in mouse tissues (Lam & Zheng 1991). (þ)-Limonene displays anticarcinogenic activity.
(1R)-(þ)-b-Pulegone is occasionally found in spearmint oils, at up to 1.0%, though this is not sufficient to be of concern. The main producing country is the USA, and four types of oil are offered: Midwest native, Farwest native, Midwest Scotch and Farwest Scotch. Scotch spearmint was introduced to the US from Scotland, and native spearmint is believed to originate from Mitcham in England.