Lemon Balm (Melissa officinalis) is a lemon-scented herb in the mint family, historically valued for its calming properties and use in treating anxiety and sleep issues. Often prepared as a tea, this perennial plant has also been studied for its potential effects on the cardiovascular system. This article explores the scientific evidence and biological mechanisms behind the claim that consuming this herbal tea can help manage or lower blood pressure, along with practical usage and safety considerations.
Scientific Evidence for Blood Pressure Effects
While lemon balm is widely known for its soothing effects, research has investigated its direct impact on blood pressure levels. Some clinical data suggests that lemon balm may have a tangible effect on hypertension. In one randomized, controlled, crossover trial involving patients with essential hypertension, a daily supplement of lemon balm extract significantly reduced both systolic and diastolic blood pressure over four weeks compared to a placebo.
This study, which used a high dosage of 1,200 milligrams per day of a hydroalcoholic extract, provides evidence of an antihypertensive effect. Furthermore, a systematic review and meta-analysis of multiple randomized controlled trials found that intake of Melissa officinalis was associated with a statistically significant decrease specifically in systolic blood pressure. This suggests a consistent, though mild, effect on the top number of a blood pressure reading.
Despite these promising findings, the overall body of evidence is not yet conclusive enough to recommend lemon balm as a standalone treatment for clinically diagnosed hypertension. Many existing studies use concentrated extracts rather than the tea preparation, and they often involve small sample sizes or short durations. Researchers agree that more large-scale, high-quality clinical trials are necessary to confirm the therapeutic efficacy of lemon balm for blood pressure management.
Understanding the Mechanism of Action
The observed effects of lemon balm on blood pressure stem from its rich composition of active plant compounds. The herb contains polyphenols, triterpenes, and phenolic acids, with rosmarinic acid being one of the most studied components. Rosmarinic acid has demonstrated a vasorelaxant effect, promoting the relaxation of smooth muscles in blood vessel walls.
This relaxation leads to a slight widening of the blood vessels, a process known as vasodilation, which helps to lower blood pressure. Lemon balm’s powerful antioxidant properties also enable it to combat oxidative stress, which damages blood vessel lining and reduces elasticity. By protecting the blood vessels, the herb may help maintain healthy circulation and flexibility.
The herb’s influence on the nervous system also plays an indirect role, as stress contributes to elevated blood pressure. Compounds in lemon balm interact with the brain’s GABA receptors, the same targets for many anti-anxiety and sedative medications. This action promotes relaxation and reduces the activation of the sympathetic nervous system, mitigating the stress response that often raises heart rate and constricts blood vessels.
Preparation and Recommended Dosage
Preparing lemon balm tea is a straightforward process that allows consumers to easily integrate the herb into their daily routine. To create a standard cup, use approximately one to two teaspoons of dried leaves, or about two tablespoons if using fresh leaves. Place the leaves in a mug, and pour hot water, ideally just below boiling at around 194°F (93°C), over them.
The steeping time is critical for extracting beneficial compounds, with a suggested range of five to ten minutes for a potent brew. Traditional herbalism often recommends consuming up to 8 to 10 grams of the dried herb daily, typically divided into several doses of tea. This differs significantly from the concentrated extracts used in clinical trials, which may be dosed around 1,200 milligrams per day.
Safety Considerations and Drug Interactions
Lemon balm is generally considered safe for most people when consumed in moderation as a tea, but there are important safety considerations and potential drug interactions. Common side effects are usually mild and may include digestive issues, such as nausea or abdominal pain, dizziness, or increased sedation. Due to its calming effects, caution is advised when combining lemon balm with other sedative medications, as this may lead to excessive drowsiness.
A more serious concern involves its potential interaction with thyroid hormone medications, such as levothyroxine. Lemon balm is thought to interfere with thyroid function and may reduce the effectiveness of thyroid hormone replacement therapy. Individuals with pre-existing thyroid conditions, particularly an underactive thyroid, should avoid using lemon balm until consulting with their healthcare provider.
Because lemon balm can lower blood pressure, consuming the tea in large amounts could potentiate the effects of prescription antihypertensive medications. This combination could potentially lead to hypotension, or blood pressure that is too low. The herb may also have a blood sugar-lowering effect, requiring careful monitoring for individuals taking diabetes medications. Anyone managing a chronic condition, especially hypertension, should speak with a physician before adding lemon balm tea to their routine.