Lemon balm (Melissa officinalis) grows really well in my garden, and also in the wild in various locations in New Zealand and other countries. It has a distinctive lemony scent when rubbed, and a plethora of medicinal uses.

Lemon balm was a sacred herb to the ancient Greeks, and widely planted by early beekeepers to keep honeybees happy and well fed with nectar. Its healing properties were increasingly recognised during the Medieval and Renaissance ages, and by the 9^th century it was widely planted in monastery gardens. Widespread medicinal uses were described by the Greek and Persian physicians Dioscorides and Avicenna and reiterated by the 17^th century English herbalist Nicholas Culpeper, who also described it as ‘an excellent remedy for a cold and moist stomach’, which ‘cheers the heart, refresheth the mind, takes away grief, sorrow and care, instead of which it produces joy and mirth’⁽¹⁾.

Like other members of the lamiaceae (mint) family of plants such as peppermint, basil, rosemary and sage, aerial parts of lemon balm can be a valuable component to the management of nervous dyspepsia and digestive conditions such as bloating and irritable bowel syndrome.  Perhaps more than anything though, its potential applications for nervous system conditions such as anxiety and mood disorders, have been increasingly supported by animal and human clinical studies in recent years.

Administration of a single dose of lemon balm to healthy student volunteers was first reported to improve cognitive performance in a laboratory model of acute stress by British researchers in 2002 ^(2-6). These and subsequent experiments measured a reduction in the negative effects of stress on mood and improved self ratings of calmness, while not causing any reduction in accuracy whilst undertaking required laboratory tasks. These effects were apparent for up to 6 hours following lemon balm administration.

A pilot trial in which 20 volunteers suffering from mild to moderate anxiety disorders and sleep disturbances took lemon balm for 15 days, found most responded to treatment, with a reduction in anxiety and associated symptoms, and an improvement in sleep⁽⁷⁾. While this was an open-label study with no placebo, and clinician contact may have contributed to the symptom improvement observed, it supports further controlled trials with larger patient numbers.

Other clinical studies have expanded our understanding of lemon balm’s relaxant properties. Favourable effects were reported in an Iranian trial in which lemon balm capsules were taken twice daily by young women with premenstrual syndrome over a 3 month period⁽⁸⁾. Those who received lemon balm reported a significant reduction in psychosomatic symptoms, anxiety and sleeping disorder, as well as improvements in social functioning difficulties.

Results from two studies involving combinations of lemon balm with other plant extracts, are also of interest. These include a small placebo controlled trial using a combination of lemon balm with the Iranian herb Nepeta menthoides (Ostokhodus) which improved insomnia, depression and anxiety in a group of 67 insomniacs⁽⁹⁾. A recent Swiss retrospective study also investigated the effects of a combination product containing lemon balm, valerian, passionflower and butterbur extracts on the prescription pattern of benzodiazepines and other psychoactive drugs in hospitalised psychiatric patients. This found concomitant prescribing of benzodiazepines for anxiety to be lower in patients taking the combination herbal product, although the level of prescribing of hypnotics and antidepressants (including herbal ones), was higher⁽¹⁰⁾.

Anxiety disorders can affect cardiovascular parameters such as the heart rate and blood pressure, and a diagnosis of a cardiovascular medical condition can cause or exacerbate anxiety. Culpeper’s comments and other traditional use information allude to an affinity for the cardiovascular system for lemon balm, and in fact two clinical trials have found favourable outcomes in this regard.

Treatment of a group of 71 volunteers suffering from an abnormal awareness of heartbeat with the equivalent of 5 grams dried lemon balm leaves daily for 14 days, resulted in less frequent and less intense symptoms of heart palpitations ^{(11, 12)}. Lemon balm treatment also reduced the number of patients with concomitant anxiety and insomnia disorder in this study. Another small trial reported a reduction in symptoms and signs of depression, anxiety, stress and sleep disorder, in a group of patients with chronic but stable angina following an 8 week course of lemon balm treatment^(13).

Recent animal studies also provide further interesting data. Adipogenesis and obesity can also accompany chronic stress, and the finding that lemon balm lead to improvements in fasting blood glucose, glucose tolerance, and pancreatic dysfunction in female obese mice, has implications for the potential prevention of visceral obesity and insulin resistance in obese premenopausal women⁽¹⁴⁾.

Another study further evaluated the effects of a hydro-alcoholic extract of lemon balm in a behavioural study in mice⁽¹⁵⁾. Reversal of behaviours reflective of anxiety and helplessness occurred following lemon balm treatment, effects accompanied by enhanced enzymatic antioxidant activities and restoration of serum corticosterone levels previously disrupted by stress.

The mechanism(s) of action of lemon balm’s anxiolytic and possible mood modulating effects, seem to involve the gamma amino butyric acid (GABA) neurotransmission system⁽¹⁶⁾. In vitro studies have reported inhibitory activity against GABA transaminase for lemon balm extracts, an enzyme involved in metabolising this endogenous ‘relaxant’ neurotransmitter.

The collective picture emerging for lemon balm and how it affects our brains and functioning, is that of a uniquely compelling and probably dose-related combination of relaxant as well as cognitive enhancing properties. Possible applications in those with accompanying digestive or cardiovascular conditions or a predisposition to obesity or depression, are also suggested. These attributes together with the various other established and likely health benefits of this easy to grow plant, would seem to make it an ideal daily tonic to help with stress management, in the modern world.

References:

1. Culpeper, Nicholas. (1653). A Complete Herbal. London, Peter Cole.
2. Kennedy DO et al,  Pharmacol Biochem Behav. 2002 Jul;72(4):953-64.
3. Kennedy DO et al. Psychosom Med. Jul-Aug 2004;66(4):607-13
4. Kennedy DO et al, Neuropsychopharmacology. 2003 Oct;28(10):1871-81.
5. Rasmussen PL, Phytonews 20, published by Phytomed Medicinal Herbs Ltd, Dec 2004.ISSN 1175-0251.
6. Rasmussen PL, Phytonews 17, published by Phytomed Medicinal Herbs Ltd, Oct 2003.ISSN 1175-0251.
7. Cases J et al, Med J Nutrition Metab. 2011 Dec;4(3):211-218.
8. Heydari N et al, Int J Adolesc Med Health. 2018 Jan 25;31(3):/j/ijamh.2019.31.issue-3/ijamh-
9. Ranjbar M et al,egr Med Res. 2018 Dec;7(4):328-332 
10. Keck et al, Phytother Res. 2020 Jun;34(6):1436-1445.
11. Alijaniha F et cl, J Ethnopharmacol 2015; 164:378-384.
12. Rasmussen PL, Phytonews 41, published by Phytomed Medicinal Herbs Ltd, Mar 2017.ISSN 1175-0251.
13. Haybar H et al, Clin Nutr ESPEN. 2018 Aug;26:47-52.
14. Lee D et al, J Ethnopharmacol. 2020 May 10;253:112646.
15. Ghazizadeh J et al, Exp Physiol. 2020 Apr;105(4):707-720
16. Awad R et al, Can J Physiol Pharmacol. 2007 Sep;85(9):933-42