Lemon balm

Lemon balm is a perennial plant from the mint family. The leaves, which have a mild lemon aroma, are used to make medicine. Lemon balm is used on its own or as part of herbal combination products. Lemon balm is used for digestive problems including indigestion, flatulence, vomiting and colic, for pain including menstrual cramps, headaches and toothache, and for mental disorders including hysteria and melancholy.

Many people believe that lemon balm has a calming effect and use it for anxiety disorders, sleep problems and restlessness. Lemon balm is also used for Alzheimer's disease, attention deficit hyperactivity disorder (ADHD), Graves' disease, swollen airways, palpitations due to nervousness, high blood pressure, ulcers, tumors and insect bites. Lemon balm is used as part of aromatherapy for Alzheimer's disease. Some people apply lemon balm to the skin to treat cold sores. Lemon balm extracts and oil are used as flavorings in foods and beverages.

Mechanisms of action of lemon balm

Increases GABA levels in the brain by inhibiting the enzyme that breaks down GABA (GABA transaminase). GABA has a calming effect, improves mood and reduces stress (1).
Binds to the nicotinic and muscarinic receptors in the brain. Both types of receptors are activated by acetylcholine and play a role in improving memory and attention (2).
Prevents the formation of blood vessels by inhibiting VEGF-A, which combats obesity and helps in the treatment of cancer
Activates the proteins caspase-3 and-7, which may help cancer cells to self-destruct (4).
Reduces inflammation by reducing TNF-alpha. It also suppresses pro-inflammatory proteins (IL-1 and IL-6) (5).

Potential health benefits of lemon balm

Lemon balm can relieve stress and anxiety

Lemon balm has antidepressant effects in rats. By increasing GABA levels, lemon balm reduces anxiety, has a calming effect and improves mood (6). In 2 pilot studies, lemon balm reduced anxiety in 32 subjects with stress (7). In another study with 55 test subjects, lemon balm supplementation also reduced anxiety (8). In a study of 71 elderly people with dementia, lemon balm aromatherapy was able to reduce agitation (9). In another study with 49 subjects, aromatherapy was able to alleviate restlessness (10). A further study with 72 healthy volunteers came to the conclusion that lemon balm in combination with valerian, butterbur extract and passionflower reduced acute stress (11).

Lemon balm can alleviate sleep disorders

In a study of 20 subjects with anxiety disorders, lemon balm was able to relieve insomnia in 85% of the subjects (12). In another with 100 women suffering from symptoms of menopause and insomnia, lemon balm was able to improve the quality of sleep (13). In a study with 900 children, lemon balm in combination with valerian was also able to alleviate sleep disorders and restlessness (14). Lemon balm could alleviate sleep disorders by increasing GABA levels in the brain, which promotes rest and relaxation (13).

Lemon balm can help with palpitations and rapid heartbeat

When taken for 14 days, an oral extract of lemon balm reduced heart rate in 55 subjects with increased heart rate (14). In studies conducted in animals and humans, lemon balm may protect against irregular heartbeat by inhibiting the sodium and potassium ion channels that slow the heart rate (16).

Lemon balm could improve memory and brain function

In two small studies involving 23 healthy volunteers, lemon balm improved cognitive performance and memory (7). In another study with 20 subjects, lemon balm was also able to improve mood and cognitive performance (17). In a study of 20 college students, lemon balm improved cognitive performance and accuracy (18). Lemon balm may improve memory and brain function by binding to the nicotinic and muscarinic receptors in the brain. Both types of receptors are activated by acetylcholine and play a role in improving memory and attention (19).

Lemon balm could be helpful for type 2 diabetes and its complications

In a clinical study involving 62 subjects with type 2 diabetes, oral supplementation with lemon balm improved blood glucose control by improving insulin sensitivity (20). In a study conducted on mice with diabetes, lemon balm was able to lower blood glucose levels and blood lipid levels. It also activates PPARs, which improves insulin sensitivity. (22). Lemon balm could help reduce the risk of cardiovascular disease In one study, lemon balm was observed to increase the amount of cholesterol bound to HDL, suggesting that lemon balm could help prevent clogging of the arteries (20). In another study of 70 subjects with diabetes, a lemon balm supplement improved blood lipid levels and levels of proteins that transport fats in the blood, which could help reduce the risk of heart disease (21).

Lemon balm could help relieve stomach upsets

For people who suffer from regular stomach pain, lemon balm may have positive effects on digestion. A small 2011 study investigated the effects of a cold dessert containing lemon balm on functional dyspepsia (a type of indigestion). The subjects ate a sorbet with or without lemon balm after a meal. Although both desserts reduced the symptoms and their intensity, the effect was more intense for the desserts with lemon balm (23).

Lemon balm can help in the treatment of nausea

Due to its effects on the digestive system, lemon balm may also help to relieve nausea. A study review that analyzed the results of several studies concluded that lemon balm is suitable for treating symptoms of the digestive tract, including nausea. However, many of these studies looked at lemon balm in combination with other medicinal herbs, so further studies are needed.

Lemon balm could relieve colic in infants

Colic is a common condition that occurs during the first few months of infants' lives. Colic is characterized by severe irritability and whining or crying in otherwise healthy infants. In a study of 200 children with colic after 28 days, lemon balm was found to reduce bouts of colic and the average time per day that children cried due to its calming effects and relaxation of the digestive tract (25). As this is the only study on the subject to date, further research is needed to confirm these effects.

Lemon balm has antioxidant properties and may protect against free radicals In a clinical study of 55 subjects working in radiology, consumption of a lemon balm infusion increased blood levels of antioxidant enzymes (catalase, superoxide dismutase and glutathione peroxidase) while reducing oxidative damage to cellular DNA and fat molecules ( 26). This suggests that lemon balm may protect against oxidative stress induced by radiation. The rosmarinic acid and salvianolic acid contained in lemon balm have also been shown in cell studies to protect skin cells from damage caused by UV radiation (27).

Lemon balm could promote weight loss

In studies conducted on mice, lemon balm suppressed the growth of adipose tissue and killed fat cells by preventing the formation of blood vessels that supply these fat cells (28). Additionally, in one study, a lemon balm extract reduced the activity of proteins involved in fat production (FABP4 and PDK4) (29). Lemon balm could be helpful in the treatment of non-alcoholic fatty liver disease Non-alcoholic fatty liver disease is caused by factors such as inflammation, high blood sugar levels and high fat consumption. In one study, lemon balm was found to help treat fatty liver disease in mice by activating enzymes that break down fatty acids. Lemon balm also reduced the activity of white blood cells and pro-inflammatory cytokines in the liver (29, 30).

Lemon balm could help in the treatment of menstrual cramps

There is research suggesting that lemon balm can be used to relieve premenstrual syndrome (PMS) and menstrual cramps. A 2015 study examined the effects of lemon balm on the intensity of menstrual cramps in 100 female high school students. The subjects took either lemon balm essence or a placebo during three consecutive menstrual periods. The intensity of PMS symptoms was measured before and one, two and three months after the study. The group that had taken lemon balm reported a significant reduction in symptoms.

Lemon balm could have anti-inflammatory properties

In a study on mice, lemon balm was able to reduce swelling caused by injuries and inflammation. In addition, lemon balm reduced the levels of pro-inflammatory proteins (TNF-alpha, IL-1 and IL-6) and oxidative stress (35).

Lemon balm could have pain-relieving effects

Alcoholic extracts of lemon balm have been shown to reduce pain in studies with mice, possibly due to a blockade of the arginine-nitric oxide pathway and an increase in acetylcholine levels (33, 34). For stress-related headaches, the relaxing properties of lemon balm could also help to reduce tension and relax the muscles. In addition, lemon balm could provide relief by relaxing constricted blood vessels that contribute to headaches. The pain-relieving properties of lemon balm and its anti-inflammatory properties could also be helpful for toothache. It can be helpful to apply diluted lemon balm oil directly to the affected area with a cotton ball.

Lemon balm could be helpful for hyperthyroidism

In a cell-based study, lemon balm reduced thyroid function by preventing thyroid-stimulating hormone (TSH) from docking to its receptor (36).

Lemon balm may have antibacterial and antifungal properties

In cell-based studies, lemon balm has shown antimicrobial effects against yeast and harmful bacterial strains (E. coli, Salmonella, Listeria and Staphylococcus). Rosmarinic acid and citral from lemon balm stopped the growth of yeast and bacteria possibly by interrupting their energy production (ATP synthase) (37) The rosmarinic acid contained in lemon balm also prevented HSV-1 (which causes oral herpes and cold sores) from attaching to cells in cell studies, which also applied to drug-resistant strains of these pathogens. The volatile oils in lemon balm also inhibited the replication of HSV-2 (genital herpes) (38, 39). However, these are very early results that have not yet been tested in humans or animals.

Lemon balm could have anti-cancer effects

Lemon balm induced a self-destruction mechanism in breast cancer cells and reduced the size of breast tumors in rats. This effect was probably based on a reduction of antigen KI-67 - a protein associated with cell growth and reproduction (40). In a cell study, lemon balm was also able to kill cancer cells in brain tumors. The citral contained in lemon balm may have activated the cancer cells' self-destruction mechanism (via capase-3) and increased the cancer's sensitivity to chemotherapy by inhibiting the MRP1 gene (41). Furthermore, lemon balm stopped the spread of leukemia cancer cells and activated their cellular self-destruction (42). In addition, lemon balm prevented the growth of colon cancer cells by arresting the cell cycle and initiating cellular self-destruction (43).

In cell models, lemon balm prevented the growth of prostate cancer cells by inhibiting the growth of blood vessels supplying the tumors. It also reduced the activity of the enzyme human telomerase reverse transcriptase (hTERT) (44). Telomeres are added to the ends of chromosomes by telomerases, but the activity of telomerases decreases with age. hTERT is overactive in cancer cells and is required for tumor growth. All of these studies have been conducted on cells and animals, so further human studies are needed to confirm these effects in humans.

Other potential health benefits

Herpes sores: Applying a lip balm containing 1% lemon balm extract to recurring cold sores appears to reduce healing time, prevent the spread of infection and reduce symptoms.
Colitis: New research suggests that taking a combination of dandelion, St. John's wort, lemon balm, calendula and fennel for 15 days reduces pain and improves digestive tract function in people with colitis.
Depression: New research suggests that taking lemon balm with fertilized egg powder does not improve symptoms of depression compared to fertilized egg powder alone.
Restlessness: New research suggests that taking one or two tablets of a specific combination product that provides 80 mg of lemon balm leaf extract and 160 mg of valerian root extract (Euvegal forte) may reduce symptoms in children under the age of 12 whose restlessness is so extreme that it requires medical attention.
Irritable bowelsyndrome: New research suggests that adding 30 drops of a product containing lemon balm, spearmint and coriander to a standard treatment three times a day after meals for 8 weeks reduces stomach pain and discomfort in people suffering from irritable bowel syndrome.
Mental illnesses that cause physical pain (somatization disorders): A product containing valerian, passionflower and lemon balm appears to reduce symptoms of depression and anxiety in people suffering from a mental illness that causes physical pain.

Safety and side effects

Lemon balm is probably safe and harmless in food quantities. It is potentially safe and harmless for adults when used in medicinal quantities for short periods of time. Lemon balm has been used safely for up to 4 months in scientific studies. Not enough is known about the safety of lemon balm for long-term use. Some information suggests that lemon balm is safe for up to one week for infants and up to one month for children under 12 years of age when used in appropriate amounts. When taken orally, lemon balm may cause some side effects including nausea, vomiting, stomach pain, dizziness and wheezing.

Precautions and warnings

Pregnancy and breastfeeding: Not enough is known about the use of lemon balm during pregnancy and breastfeeding. For this reason, pregnant and breastfeeding women should avoid lemon balm.
Children: Lemon balm may be safe for children when taken orally for short periods of time.
Surgeries: Lemon balm could cause excessive drowsiness when combined with medications used during and after surgery. For this reason, the use of lemon balm should be discontinued at least 2 weeks before planned operations.

Interactions

Care should be taken when combining lemon balm with the following medications:

Sedatives (CNS suppressing agents)

Lemon balm can cause drowsiness and dizziness. Drugs that cause drowsiness are called sedatives. Taking lemon balm in combination with sedatives could cause excessive drowsiness.

Dosage

The following dosages have been investigated in scientific studies:

Oral:

For mild to moderate Alzheimer's disease: 60 drops of a standardized lemon balm extract, prepared in a 1:1 ratio with 45% alcohol.
To improve sleep in healthy adults: A specific combination product providing 80 mg lemon balm leaf extract and 160 mg valerian root extract (Euvegal forte) was used three times daily for up to 30 days. The same combination product was used once or twice daily to improve sleep in children.
For stomach upset: A specific combination product containing lemon balm and several other plant extracts (Iberogast) was used at a dosage of 1 ml three times a day for a period of 4 weeks. This combination product contains lemon balm, peppermint leaf, chamomile, caraway, licorice root, bitter bowslip, celandine, angelica and milk thistle.
For colic in breastfed infants: a specific combination product containing 164 mg fennel, 97 mg lemon balm and 178 chamomile (Colimil) was used twice daily for one week.

Applied to the skin:

For cold sores: a cream containing 1% of a 70:1 freeze-dried, water-soluble extract is usually used two or four times daily from the onset of the first symptoms until a few days after the blisters have healed.