Lemon balm (Melissa) — The GABA-Preserving Botanical

Lemon balm (Melissa officinalis) exerts its primary neuro-active effects through rosmarinic acid and other phenolic compounds. These compounds inhibit GABA transaminase (GABA-T), the enzyme responsible for degrading gamma-aminobutyric acid (GABA), thereby increasing GABAergic tone in the brain. It also exhibits cholinergic properties by inhibiting acetylcholinesterase (AChE), which may explain its cognitive benefits. Additionally, its potent antioxidant capacity reduces oxidative stress and neuroinflammation.

Multiple small clinical trials demonstrate efficacy for mild-to-moderate anxiety and sleep disturbances. A 2003 double-blind, placebo-controlled trial (Akhondzadeh et al.) showed cognitive benefits in patients with mild-to-moderate Alzheimer's disease. Recent trials also suggest potential benefits for depression and anxiety in patients with type 2 diabetes.

300–600 mg of standardised extract per day is the most studied range in clinical trials for anxiety and sleep. Crude herb is typically dosed at 1.5 to 4.5 g/day as a tea or infusion. Best taken in the evening or before bed when used for sleep support.

Generally well-tolerated in short-term use. May cause mild sedation, nausea, or abdominal pain. Contraindicated in individuals with thyroid disorders (particularly hypothyroidism and Hashimoto's) as it may interfere with thyroid hormone function. May interact with sedatives, CNS depressants, and thyroid medications. Long-term continuous use is not recommended without medical supervision.

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