Lemon Balm

Melissa officinalis L. belongs to Lamiaceae, the mint family, alongside peppermint, sage, thyme, and rosemary. NCBI Taxonomy files it as taxon 39338. Engels and Brinckmann’s profile for the American Botanical Council (HerbalGram 2017) describes an erect herbaceous perennial about a metre tall with sparsely hairy, toothed leaves that smell and taste of lemon. Unlike many mints it does not have invasive roots; it spreads instead by seed, each small yellow to pinkish-white flower producing four tiny seeds that germinate easily. The genus has only four accepted species, and M. officinalis has three main subspecies (officinalis, altissima, and inodora) and at least 15 named cultivars. The genus originated in the region from the Mediterranean to western and central Asia, and the plant is now cultivated widely in Europe, North Africa, and the Americas.

The medicinal part is the dried leaf, defined in the European Pharmacopoeia, which requires at least 1% rosmarinic acid. EMA’s monograph covers the cut leaf for tea, the powdered leaf, a liquid extract (1:1) and a tincture (1:5) made with 45–53% ethanol, and dried water or ethanol extracts equivalent to those preparations. The essential oil is a separate and very different product: EMA’s assessment report gives an oil content of only 0.06–0.8% of the dried leaf, so a cup of tea delivers relatively little of it. Germany is the largest market; HerbalGram puts its annual demand at about 1.5 million kg, most of it imported.

EMA’s assessment report lists the main constituents. The essential oil is dominated by the monoterpene aldehydes citral, a mixture of neral and geranial (PubChem CID 638011), and citronellal (CID 7794), with β-caryophyllene and germacrene D each making up about 10% of the oil. The leaf also contains flavonoid glycosides of luteolin, quercetin, apigenin, and kaempferol; the triterpenes ursolic and oleanolic acid; tannins; and phenolic acids, especially rosmarinic acid (CID 5281792, C18H16O8), at up to 6% of the leaf. Rosmarinic acid is the compound the European Pharmacopoeia uses to set the minimum quality standard for the leaf. HerbalGram notes at least three chemotypes defined by the oil: citral, germacrene, and caryophyllene types, so the scent and composition of plants and products can differ.

HerbalGram traces the name Melissa to the Greek word for bee, after the plant’s strong attraction for honeybees; Linnaeus assigned the genus in 1737, and in 1543 the German physician Leonhart Fuchs recorded the folk names Melissen and Honigblum (honey flower) for the same reason. One of the earliest descriptions appears in the Historia Plantarum of the Greek botanist Theophrastus. Remains of lemon balm were found in a rodent nest inside a classical bronze statue of an athlete recovered from the northern Adriatic, dating from between the first century BCE and second century CE. The Moors introduced the plant to Spain in the tenth century, Benedictine monks carried it into central Europe, and the abbess Hildegard von Bingen described its medicinal uses in her Physica in the 1150s.

Carmelite water made lemon balm famous. According to HerbalGram, Discalced Carmelites in Paris began cultivating lemon balm around 1611 and distilled Eau de Carmélite, which became a popular remedy for toothache, fainting, and anxiety. During the French Revolution two Carmelite nuns fled Paris to a convent in Baden-Baden with the secret recipe, and in Germany the preparation became known as Melissengeist, an alcoholic spirit of melissa. In December 2005 Klosterfrau Melissengeist became the first product in Europe registered under the EU’s new law on traditional herbal medicinal products.

Modern regulation built on the old handbooks. EMA’s assessment report cites traditional use in German texts from Madaus in 1938 and in the British Herbal Pharmacopoeia of 1983, and notes powdered leaf capsules marketed in France since 1981. Germany’s Commission E approved lemon balm in 1984 for nervous sleeping disorders and functional gastrointestinal complaints, and in 1997 the European Scientific Cooperative on Phytotherapy (ESCOP) listed it internally for tenseness, restlessness, and irritability and externally for cold sores. The European Pharmacopoeia adopted a standard for melissa leaf in 2000. EMA’s Committee on Herbal Medicinal Products published its first monograph in 2007 and a revised monograph on 14 May 2013, recognizing traditional use only; in 2024 it opened a call for new scientific data for a periodic review. In the United States, the FDA classifies lemon balm as generally recognized as safe as a spice and flavouring.

The calming effects have several proposed mechanisms, all from laboratory and animal work summarized in EMA’s assessment report. An aqueous extract inhibited GABA transaminase, the enzyme that breaks down the calming neurotransmitter GABA, in rat brain tissue. A standardized ethanolic extract (Cyracos) reduced anxiety-like behaviour in mice without affecting general activity, and the essential oil interacted with the GABA-A receptor channel in rat brain membranes. Extracts also bound to nicotinic and muscarinic acetylcholine receptors in human brain tissue, though Kennedy and colleagues (Pharmacology Biochemistry and Behavior 2002) found the binding of their extract to be low. Sedative effects were seen in mice. How much of this happens at the doses people actually take is unknown.

For digestion the picture is less clear. EMA reports that the essential oil and its main component citral relaxed isolated rat and guinea pig intestine in the laboratory, but a 30% ethanolic leaf extract showed no significant antispasmodic activity on guinea pig ileum, and another ethanolic extract had no effect on the rhythmic activity of mouse small intestine. Because tea contains little oil, the mechanism behind the traditional use for bloating and wind is not established.

Antiviral and hormonal effects are better characterized in the laboratory. HerbalGram cites studies showing that lemon balm extracts and oil inhibit herpes simplex virus, including blocking attachment of acyclovir-resistant strains to cells. EMA notes that the cold sore cream uses a highly purified aqueous extract (70:1) whose major components are caffeic, chlorogenic, and rosmarinic acids, standardized by its antiviral activity in a plaque inhibition test. EMA also notes in vitro and animal data indicating that water extracts may inhibit the activity of thyroid-stimulating hormone (TSH), with unknown clinical relevance. Noguchi-Shinohara and colleagues tested lemon balm as a source of rosmarinic acid because it inhibits amyloid-β fibril formation in Alzheimer’s disease models.

Stress and calm: Kennedy, Little, and Scholey (Psychosomatic Medicine 2004) gave 18 healthy volunteers single doses of 300 mg and 600 mg of a standardized extract and placebo on separate days before a laboratory stress task. The 600 mg dose reduced the negative mood effects of the stressor, increasing self-rated calmness and reducing alertness, and 300 mg speeded mathematical processing without loss of accuracy. In an earlier trial in 20 young adults described by EMA, 600 mg improved accuracy of attention, but higher doses reduced memory performance and the highest, 900 mg, reduced alertness, a reminder that calming and sedating overlap. EMA notes that these studies used methanol extracts not covered by its monograph and considered them of questionable relevance to the traditional use.

Anxiety and sleep: Cases and colleagues (Mediterranean Journal of Nutrition and Metabolism 2011) gave 20 stressed adults with mild to moderate anxiety and sleep disturbance 600 mg per day of the Cyracos extract for 15 days. Anxiety scores fell by 18% and insomnia by 42%. EMA judged the study insufficient because it was open-label, had no control group, and was too small. Ghazizadeh and colleagues (Phytotherapy Research 2021) pooled randomized trials and found lemon balm improved anxiety scores (standardized mean difference −0.98) and depression scores (−0.47) compared with placebo without serious side effects, particularly in acute settings, but warned that high heterogeneity, few trials, and differing methods mean the results should be interpreted with caution. The EU indication remains a traditional one: relief of mild symptoms of mental stress and to aid sleep.

Cold sores: Koytchev, Alken, and Dundarov (Phytomedicine 1999) randomized 66 people with at least four cold sore episodes a year to a cream containing 1% of a 70:1 dried lemon balm leaf extract or placebo, applied four times daily for five days. On day two, when symptoms are usually worst, a combined score of discomfort, lesion size, and blisters was significantly lower on the active cream. Anheyer and colleagues (Journal of Integrative and Complementary Medicine 2025) reviewed seven randomized trials of topical herbal treatments for cold sores with 1,250 patients in total and found that lemon balm preparations consistently reduced pain and swelling, with some trials showing smaller lesions, though samples were small and most trials raised some concern about bias. EMA notes that the data for this specific extract cannot be transferred to other lemon balm products.

Dementia and memory: Akhondzadeh and colleagues (Journal of Neurology, Neurosurgery and Psychiatry 2003) randomized 42 people aged 65 to 80 with mild to moderate Alzheimer’s disease to 60 drops a day of lemon balm extract or placebo for four months and reported better cognitive scores and less agitation with the extract; EMA considered this one small trial insufficient. Ballard and colleagues (Journal of Clinical Psychiatry 2002) found that a lotion containing lemon balm essential oil, applied to the face and arms of 72 care-home residents with severe dementia, reduced agitation by 35% versus 11% with placebo over four weeks. But Burns and colleagues (Dementia and Geriatric Cognitive Disorders 2011), in a trial of 114 people with Alzheimer’s disease in which raters wore nose clips to keep blinding intact, found melissa aromatherapy no better than placebo or donepezil for agitation; all groups improved. Noguchi-Shinohara and colleagues (Journal of Alzheimer’s Disease 2023) gave 323 older adults with subjective or mild cognitive impairment an extract providing 500 mg of rosmarinic acid daily or placebo for 96 weeks and found no difference in cognitive measures; a subgroup signal in people without high blood pressure needs confirmation.

Other uses: Alijaniha and colleagues (Journal of Ethnopharmacology 2015), testing a use from traditional Iranian medicine, gave adults with benign palpitations 500 mg of a freeze-dried aqueous leaf extract or placebo twice daily for 14 days; of 71 recruited, 55 completed, and the extract reduced the frequency of palpitations and the number of anxious participants. Palpitations must be medically assessed before being called benign. HerbalGram notes positive trials of lemon balm in combination products, with valerian for sleep, with chamomile and fennel for infant colic, and in a multi-herb formula for indigestion, but combinations cannot show what lemon balm contributes, and HerbalGram concludes that high-quality trials of lemon balm alone are few. No trials of lemon balm alone for bloating or wind were identified by EMA.

EU traditional use (EMA/HMPC/196745/2012, adopted 14 May 2013), for adolescents over 12, adults, and older people, for mild stress, sleep, or mild digestive complaints: herbal tea, 1.5–4.5 g of cut dried leaf in 150 ml of boiling water as an infusion, one to three times daily; powdered leaf, 0.19–0.55 g two to three times daily; liquid extract (1:1, 45–53% ethanol), 2–4 ml one to three times daily; tincture (1:5, 45–53% ethanol), 2–6 ml one to three times daily; or dried extracts in equivalent doses. Use in children under 12 is not recommended. If symptoms persist longer than two weeks or worsen, see a doctor or qualified healthcare practitioner. Tinctures and liquid extracts contain alcohol.

Clinical trials used specific extracts, which are not interchangeable with tea or with each other: single doses of 300–600 mg of standardized extract in the laboratory stress studies; 600 mg per day of Cyracos, standardized to more than 7% rosmarinic acid, in the open anxiety study; 500 mg of freeze-dried aqueous extract twice daily for palpitations; 60 drops per day of a 1:1 extract in 45% alcohol in the Alzheimer’s trial; and an extract supplying 500 mg of rosmarinic acid daily for 96 weeks in the Japanese prevention trial. Choose products that state the plant part, extract type and ratio, and any standardization, and that are made to pharmacopoeial quality.

Topical: the cold sore trial used a cream containing 1% of a 70:1 purified aqueous leaf extract, applied four times daily for five days. Keep creams away from the eyes. Cold sores that are frequent, very large, slow to heal, near the eye, or in someone with a weakened immune system need medical advice; antiviral drugs remain the standard treatment. The dementia trials applied lotions containing lemon balm essential oil to the skin as aromatherapy; essential oils are concentrated, should not be swallowed, and should be stored out of children’s reach.