Lemon Balm for Sleep and Anxiety: What the Extract Trials Show

TL;DR

Lemon balm has more human trial evidence than most calming herbs, and the strongest signal is on anxiety and mood rather than sleep. A 2024 crossover trial of a standardized extract improved insomnia scores and shifted sleep stages. Two other extract trials found no sleep benefit at all. Much of the older evidence used lemon balm combined with valerian or other herbs, and one large combination trial lost to placebo outright. Doses in the trials ranged from 400 mg of a concentrated extract to 3 grams of plain supplement, and those numbers don't transfer between products.

The supplement is a different thing from the tea

Lemon balm is Melissa officinalis, a member of the mint family. It's been used as a calming herb for centuries and it turns up in tea aisles, herb gardens, and kitchens.

The research below tested none of that. Every trial used a measured oral extract in a capsule or tablet, standardized to a known content of active compounds, usually rosmarinic acid and related hydroxycinnamic acids. Those extracts are concentrated to a degree a cup of tea doesn't approach, and the amount of active compound in loose leaf or a teabag varies with the plant, the harvest, and how long you steep it.

So the evidence here belongs to supplements. A cup of lemon balm tea is a pleasant thing and it isn't what these researchers gave anyone.

The proposed mechanism is inhibition of GABA transaminase, the enzyme that breaks down GABA, which is attributed largely to rosmarinic acid (Di Pierro 2024). Reviewers describe lemon balm as modulating GABAergic, cholinergic, and serotonergic signalling based on animal and cellular work (Mathews 2024).

The anxiety evidence

This is where lemon balm performs best.

A systematic review and meta-analysis pooled the randomized trials published to October 2020. Lemon balm improved anxiety scores against placebo with a standardized mean difference of -0.98 (95% CI -1.63 to -0.33, p = 0.003) and depression scores with an SMD of -0.47 (-0.73 to -0.21, p = 0.0005), without serious side effects. The authors flagged high heterogeneity between studies and said results should be read with caution (Ghazizadeh 2021).

The largest single trial gave 100 healthy adults with moderate depression, anxiety, stress, or poor sleep either 200 mg of a phospholipid-carrier lemon balm extract twice daily, so 400 mg a day, or placebo for three weeks. Depressive mood, anxiety, stress, emotional affect, mental wellbeing, and quality of life all improved (all p values below 0.001), and the supplement was well tolerated (Bano 2023). The results the authors list are all mood and wellbeing measures. The trial recruited people with poor sleep and reported no separate sleep outcome.

In 80 patients with chronic stable angina, 3 grams of lemon balm daily for eight weeks lowered depression, anxiety, stress, and total sleep disturbance scores against placebo (Haybar 2018).

In 60 people with type 2 diabetes and depressive symptoms, 700 mg a day of a hydroalcoholic extract for 12 weeks improved depression (p < 0.001) and anxiety (p = 0.04) against placebo (Safari 2023).

Every one of those populations was selected for having something to improve. None tested lemon balm in people who were already calm.

The sleep evidence, which is thinner and mixed

The best sleep result comes from a 2024 double-blind, placebo-controlled crossover trial of a standardized lemon balm extract formulated as a phytosome to raise absorption of its polyphenols. Insomnia Severity Index scores in the treated group averaged 6.8 against 9.7 on placebo, a reduction of 2.9 points (p = 0.003). Slow wave sleep duration rose about 15 percent and REM fell about 10 percent. Eighty-seven percent of the treated group reported better sleep against 30 percent on placebo. Anxiety levels showed no significant change (Di Pierro 2024). The study's lead author is the scientific director of the company that makes the ingredient, and two co-authors consult for it.

Set against that, two trials found nothing on sleep. The type 2 diabetes trial measured Pittsburgh Sleep Quality Index scores and found no significant difference between lemon balm and placebo, even while depression and anxiety improved (Safari 2023). The three-week trial in 100 adults reported mood and wellbeing gains without a sleep result (Bano 2023).

An earlier open-label pilot is the source of the most quoted lemon balm sleep number. Twenty volunteers with mild to moderate anxiety and sleep disturbance took a standardized extract for 15 days. Anxiety fell 18 percent, anxiety-associated symptoms 15 percent, and insomnia 42 percent, with 85 percent reaching full remission for insomnia (Cases 2011). Read the design before the numbers. There was no placebo group, and the authors closed by saying it is critical that further studies incorporate one.

The combination problem

A large share of the human research on lemon balm gave it alongside other herbs, and results from those trials belong to the mixtures.

The most instructive is a 2024 randomized placebo-controlled trial in 64 adults with impaired sleep. They received a formulation containing L-theanine plus lemon balm, valerian, and saffron extracts, or placebo, for six weeks, with actigraphy for objective measurement. Sleep efficiency stayed flat in the active group and rose 3 percent on placebo. Total sleep time improved more on placebo, 13 minutes against 1.33. Pittsburgh scores fell 32.3 percent on the formulation and 39.5 percent on placebo. The authors concluded the combination did not improve objective or subjective sleep more than placebo (Gutiérrez-Romero 2024).

A 2006 crossover trial tested lemon balm combined with valerian in 24 healthy volunteers at three doses during a laboratory stressor. The 600 mg dose reduced stress-induced anxiety. The 1,800 mg dose increased anxiety. All three doses worsened performance on a Stroop task, and the two lower doses worsened the overall battery score (Kennedy 2006). More was worse, which is the opposite of how supplement dosing is usually described.

A trial in postmenopausal women with sleep disturbance used lemon balm combined with fennel fruit extract against citalopram and placebo (Shirazi 2021).

None of these results can be assigned to lemon balm on its own.

Doses, and why milligram numbers don't transfer

The trials used wildly different amounts, and the reason is that they used wildly different preparations.

400 mg a day of a phospholipid-carrier extract (Bano 2023). 700 mg a day of a hydroalcoholic extract (Safari 2023). 3 grams a day of a plain supplement (Haybar 2018). 600 mg of a standardized combination product (Kennedy 2006).

A 400 mg dose of a concentrated phospholipid-carrier extract and a 400 mg dose of dried leaf powder are not comparable, because the amount of rosmarinic acid and related compounds differs by an order of magnitude. The phytosome and phospholipid formulations exist specifically because the plain extracts absorb poorly, a limitation the researchers behind the 2024 sleep trial named as their reason for reformulating (Di Pierro 2024).

The practical version: check what the extract is standardized to rather than comparing milligram totals across bottles. No published trial has tested 300 mg of lemon balm on its own for sleep or anxiety.

Safety

The meta-analysis reported improvements without serious side effects across the pooled trials (Ghazizadeh 2021). The three-week trial at 400 mg daily reported good tolerability with no treatment-emergent effects or serious adverse events (Bano 2023).

The dose-inversion in the valerian combination trial is worth carrying forward, though. Higher was not better there, and one dose made anxiety worse (Kennedy 2006).

Where the evidence is soft

Trials are small. The sleep crossover, the diabetes trial, and the angina trial each ran in fewer than 100 people, and the most-quoted pilot had 20 with no placebo arm.

Funding recurs. The 2024 sleep trial was run by people connected to the ingredient maker, and the 2024 review was funded by an ingredient company with two of its employees as authors (Mathews 2024).

Populations are specific. Angina patients, people with type 2 diabetes and depression, postmenopausal women. Transferring those results to a healthy adult who sleeps badly involves a leap.

And the direction of effect is clearer for mood than for sleep, which is the reverse of how lemon balm usually gets marketed.

For the other calming ingredients with their own evidence, see l-theanine benefits, glycine for sleep, and apigenin for sleep. For magnesium, see which magnesium is best for sleep and anxiety.

FAQ

Does lemon balm actually help you sleep?

One well-designed crossover trial of a high-absorption extract improved insomnia scores by 2.9 points and shifted sleep stages (Di Pierro 2024). Two other extract trials found no sleep benefit (Safari 2023, Bano 2023). The anxiety evidence is stronger and more consistent than the sleep evidence.

How much should I take?

Trials used 400 mg of a concentrated extract, 700 mg of a hydroalcoholic extract, and 3 grams of a plain supplement. Those aren't interchangeable numbers, because the preparations differ in strength. Check what a product is standardized to rather than comparing milligrams.

Is lemon balm tea the same thing?

No. Every trial cited here used a measured, standardized extract in capsule or tablet form. Tea delivers an uncontrolled and much smaller amount of the active compounds.

Does it work with valerian?

Combination trials exist and their results belong to the combinations. A four-herb formulation containing lemon balm and valerian failed to beat placebo on sleep over six weeks (Gutiérrez-Romero 2024). A lemon balm and valerian product reduced lab-induced anxiety at 600 mg and increased it at 1,800 mg (Kennedy 2006).

How long before it does anything?

The trials ran from 15 days to 12 weeks. The three-week trial saw mood changes by the end of that period (Bano 2023), and the angina trial ran eight weeks (Haybar 2018).

Disclaimer

This article is for general information only. It is not medical advice and it does not replace guidance from a qualified healthcare professional. Lemon balm may affect thyroid function, so anyone with a thyroid condition or taking thyroid medication should seek medical advice before using it. It may add to the effects of sedative medication. People who are pregnant or breastfeeding, and anyone taking prescription medication for anxiety, sleep, or mood, should speak with a doctor first. Do not use this information to diagnose or treat any condition. Speak with your doctor before starting any supplement.