What is it?
An extract of the leaves of spearmint, Mentha spicata, the mint used fresh or dried as a seasoning and brewed as an herbal tea. Spearmint essential oil gets its scent mainly from carvone, while a water extract of the leaves studied in detail was dominated by rosmarinic acid and related polyphenols. How much of the fragrant oil an extract carries depends on the plant and the extraction method. In cosmetics it is listed as a skin-conditioning ingredient.
Key information
- The FDA lists spearmint among spices and natural seasonings that are generally recognized as safe (GRAS).
- In a 90-day study, rats given a dried spearmint extract with 15.4 percent rosmarinic acid showed no adverse effects at the highest dose tested, and the extract was not mutagenic in lab tests.
- The EU labels spearmint oil as a fragrance allergen; the leaf extract is not named, but carvone, the oil's main scent compound, must be declared above 0.001 percent in leave-on products.
- We found no safety assessment of spearmint leaf extract by the Cosmetic Ingredient Review or the EU's Scientific Committee on Consumer Safety.
More information
Spearmint is a common culinary mint. Its essential oil is mostly carvone (roughly 22 to 73 percent in traditional cultivars) and limonene, while water extracts of the leaves are rich in polyphenols. A 2016 analysis of a dried water extract made from spearmint bred for high rosmarinic acid tentatively identified 66 phenolic compounds, led by rosmarinic acid and its derivatives, and found only trace amounts of carvone.
The same type of extract was tested in a 90-day study in which rats were given up to 1,948 mg per kilogram of body weight a day by stomach tube. There were no treatment-related adverse effects, and the highest dose was set as the no-observed-adverse-effect level; some gland weights rose, which the authors judged non-adverse because tissue examination showed no changes. The extract was not mutagenic in the Ames test and did not damage chromosomes in human blood cells. These were oral studies. We found no skin irritation or allergy studies of the leaf extract and no safety assessment by the Cosmetic Ingredient Review (CIR) or the EU’s Scientific Committee on Consumer Safety.
The EU lists spearmint oil as a fragrance allergen, and since August 2026 new products must name it on the label above 0.001 percent in leave-on or 0.01 percent in rinse-off products. That rule covers the oil, not the leaf extract, but carvone itself must be declared above the same thresholds. People who know they react to spearmint can check labels for Mentha Spicata Leaf Extract, spearmint oil (Mentha Viridis Leaf Oil) and carvone. See also our Peppermint Oil profile.
Sources: Molecules (2016): Phenolic and Volatile Composition of a Dry Spearmint (Mentha spicata L.) Extract; Regulatory Toxicology and Pharmacology (2015): The safety of a dry spearmint extract in vitro and in vivo; Cornell LII: 21 CFR 182.10, Spices and other natural seasonings and flavorings; EUR-Lex: Commission Regulation (EU) 2023/1545 on labelling of fragrance allergens
