Lemon balm: food uses, research and precautions

Identity: which plant and which preparation?

Lemon balm, Melissa officinalis L., is a perennial herb in the mint family, Lamiaceae. Its edible leaves are green, wrinkled, oval to heart-shaped and toothed at the edges; they release a lemon scent when bruised. Young leaves can be particularly flavorful. This guide concerns leaves sold or grown for food, not an unidentified wild plant selected by smell alone. [1]

Lemongrass and lemon verbena are different plants, even though all three may smell lemony. Use the scientific name on the label to distinguish them. Fresh leaves, dried leaves, a strained infusion, a standardized extract and essential oil are also different products. A preparation made for the skin is not interchangeable with one intended for the mouth. [2] [12]

Useful food roles and nutritional meaning

The clearest everyday benefit is flavor and variety. Chopped fresh leaves suit green or fruit salads, soups and sauces; they can also flavor pesto or garnish an iced drink. Start with a few leaves in a serving and adjust to taste. This is a cooking starting point, not a medical dose. Lemon balm can make an unsweetened herbal drink more appealing without requiring added sugar. [1] [3]

The reviewed food-use sources do not provide a reliable nutrient analysis for an ordinary fresh-leaf portion. It would therefore be misleading to assign a mug or garnish a large vitamin or mineral contribution. Lemon fragrance is not evidence of the vitamin C content of a lemon. Eating chopped leaves and drinking an infusion from which the leaves have been removed are different forms of consumption. [3] [4]

Chemical composition also needs context. A studied leaf extract contained phenolic compounds, including rosmarinic acid, as well as flavonoids and triterpenes. These plant compounds are not a substitute for the nutrients in a varied diet. The extract was standardized and chemically analyzed; its composition cannot be assumed for a handful of garden leaves or a homemade tea. [9]

Selecting, preparing and storing the leaves

Choose sound leaves without slime, mold or extensive deterioration. Wash your hands, rinse the leaves under cool running water and pat dry. Use clean utensils and keep the herb away from raw meat and its juices. Do not wash food with soap, detergent or bleach. Washing does not restore spoiled leaves. [6]

For an ordinary infusion, place clean fresh or dried food-grade leaves in a cup, add hot water, steep for several minutes and strain. Adjust the amount to flavor or follow the food product's directions. The reviewed clinical studies do not establish a therapeutic fresh-leaf amount or a home-tea recipe. Their milligram doses refer to specific extracts and should not be converted into spoonfuls of leaves. [4] [8] [9]

Harvest leaves for fresh use as needed; for drying or freezing, Iowa State recommends harvesting just before flowering. Dry in an airy, dark place, then remove the leaves from the stems and keep them in closed containers. Drying can reduce the fresh lemon aroma; freezing is another way to preserve surplus leaves for later cooking. Keep prepared, chopped herbs refrigerated and use them promptly. [3] [5] [6]

Homemade pesto and ordinary mixtures of herbs in oil should be refrigerated promptly and used within 4 days or frozen. Oil does not make moist herbs safe at room temperature: conditions under oil can permit botulism. This storage limit also applies when lemon balm is the herb in the mixture. [7]

What have human studies shown?

A 2004 randomized, double-blind crossover trial in 18 healthy volunteers compared single doses of 300 mg and 600 mg of a standardized extract with placebo, on separate days. During a laboratory stress task assessed one hour after dosing, 600 mg improved self-rated calmness but also reduced self-rated alertness. At 300 mg, mathematical processing was faster without reduced accuracy. These are short-term findings from a small, healthy group under artificial stress, not proof of treatment for an anxiety disorder or an effect from ordinary tea. The original abstract was reviewed. [8]

A 2011 pilot study in 20 adults aged 18–70 with mild-to-moderate anxiety and sleep disturbances used 600 mg daily of a hydroalcoholic leaf extract, divided into two 300 mg doses, for 15 days. Clinician-rated symptoms improved and no adverse effects were reported. However, everyone received the extract: there was no placebo group and no blinding. Natural fluctuation, expectation and other influences cannot be separated from treatment. Several authors were affiliated with the extract manufacturer. This preliminary study cannot establish lasting efficacy or broad safety. [9]

Common claims: what does the evidence say?

Claim: “Lemon balm tea is a proven treatment for insomnia.” → Verdict: not established by the studies reviewed here. The sleep study used a particular extract and lacked a control group. Neither its dose nor its result can simply be transferred to a cup of leaves. [9]

Claim: “A natural calming product cannot reduce alertness.” → Verdict: contradicted under one studied extract condition. Reduced self-rated alertness accompanied greater calmness after 600 mg in the stress trial. This does not mean every food portion has that effect, but “natural” is not a guarantee of unimpaired attention. [8]

Claim: “Lemon balm can replace thyroid medicine.” → Verdict: not supported by the clinical evidence reviewed. The pilot excluded people with both underactive and overactive thyroid disease. Laboratory hypotheses do not justify changing prescribed thyroid treatment. [9]

Safety, medicines and special situations

Alertness and medicines: do not drive or operate machinery if a preparation makes you drowsy. The pilot excluded people using anxiety medicines, antidepressants, sleep-inducing medicines or sedatives; it therefore does not establish that adding its extract to those treatments is safe. Discuss the actual product and dose with the prescriber, and do not stop prescribed treatment because of these small studies. A clinical drug interaction should not be presented as proven merely because a sedative effect is plausible. [8] [9]

Thyroid disease and other conditions: exclusion from the pilot limits what its findings can tell people with thyroid disease; it is not evidence that ordinary leaves interfere with thyroid medicines. Diabetes and asthma were also exclusion criteria. These exclusions do not establish contraindications, but prevent claims that this study demonstrated supplement safety in those groups. [9]

Pregnancy, breastfeeding and children: the pilot excluded pregnancy and breastfeeding and enrolled adults. It does not establish medicinal doses for those groups or children. Washed herbs used to flavor a meal are distinct from repeated medicinal preparations. Do not use this article as a basis for treating pregnancy symptoms, increasing milk production or giving a child a sleep remedy. [10] [9]

Allergy and essential oil: avoid a known allergy trigger. Stop a product that causes a suspected allergic reaction; breathing difficulty or throat swelling requires emergency medical help. Do not swallow essential oil or give it to children by mouth. Concentrated oils can be toxic when swallowed and can irritate skin; keep them out of children's reach. A topical product's instructions or evidence cannot be transferred to drinking it. [11] [12]

Conclusion

Lemon balm is useful as a fragrant food herb and an ingredient in a pleasant herbal drink. Fresh leaves, dried leaves and extracts serve different purposes. Small studies suggest specific short-term effects on calmness or symptom ratings, with important limits and possible reduced alertness. Enjoy culinary use with sound identification, washing and storage, and treat medicinal preparations as separate decisions requiring attention to the product, medicines and the person using it.