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Supplement · Grade B

Lemon Balm and medications.

Every documented pair, every citation. Below: 13 documented pairs grouped by mechanism.

Lemon Balm is in the Distil supplement database, evidence Grade B. The page below lists every medication we have explicitly assessed it against.

Lemon balm is a mint-family herb taken as a standardised extract, typically 300 to 900mg a day, with around 600mg used for acute anxiety. It appears to act on the GABA system, a calming pathway distinct from how L-theanine works, which is why the two are sometimes considered separately. The evidence is Grade B for both anxiety and sleep and for digestive complaints like IBS bloating and spasm. Trials by Haybar in 2018 and Scholey in 2014 suggest it may reduce anxiety, stress and sleep disturbance and support mood, though sample sizes are modest and the field is still small. It combines well with valerian for sleep onset, where the pairing has its own Grade B support. Two interactions are worth noting: it adds to the sedation of other CNS depressants, and because it may modulate TSH it is worth using with awareness in people with thyroid conditions. It is very safe, with mild sedation the main effect.

Below are the 13 documented pairs we have explicitly assessed for Lemon Balm: 13 amber. The pairs cluster around 3 mechanisms: Additive CNS sedation, Additive CNS depression, and Reduced thyroid-hormone effect. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not listed here is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by medication, and the missing-item form at the bottom of the page routes any uncatalogued medication into our next curation pass.

Documented interactions

Additive CNS sedation

Amber Clonidine

Lemon balm can make you drowsy, and clonidine commonly causes drowsiness and tiredness too. Taken together they may add to the sedation and slow your reactions more than either alone. Use with care, particularly around driving, and especially in the first weeks.

BNF: Lemon balm · BNF: Clonidine

Reviewer-flagged: awaiting clinical-reviewer sign-off.

Amber Guanfacine

Lemon balm can make you drowsy, and guanfacine commonly causes drowsiness and tiredness too. Taken together they may add to the sedation and slow your reactions more than either alone. Use with care, particularly around driving, and especially in the first weeks.

BNF: Lemon balm · BNF: Guanfacine

Reviewer-flagged: awaiting clinical-reviewer sign-off.

Additive CNS depression

Amber Alprazolam

Lemon balm and alprazolam both calm the nervous system through overlapping pathways. Combining them may mean stronger drowsiness, slower reaction time, and a heavier morning grogginess than either tends to give on its own. Use with care, particularly around driving.

PMID 39683592 · PMID 29908682 · BNF: Alprazolam

Lemon balm and chlordiazepoxide both calm the nervous system through overlapping pathways. Combining them may mean stronger drowsiness, slower reaction time, and a heavier morning grogginess than either tends to give on its own. Use with care, particularly around driving.

PMID 39683592 · PMID 29908682 · BNF: Chlordiazepoxide
Amber Diazepam

Lemon balm and diazepam both calm the nervous system through overlapping pathways. Combining them may mean stronger drowsiness, slower reaction time, and a heavier morning grogginess than either tends to give on its own. Use with care, particularly around driving.

PMID 39683592 · PMID 29908682 · BNF: Diazepam
Amber Lorazepam

Lemon balm and lorazepam both calm the nervous system through overlapping pathways. Combining them may mean stronger drowsiness and slower reactions than either tends to give on its own.

PMID 39683592 · PMID 29908682 · BNF: Lorazepam
Amber Nitrazepam

Lemon balm and nitrazepam both calm the nervous system through overlapping pathways. Both are used around sleep, so combining them may mean deeper-than-intended sedation and a heavier morning grogginess, made more likely by nitrazepam's long action. Take care around driving the next morning.

PMID 39683592 · PMID 29908682 · BNF: Nitrazepam
Amber Oxazepam

Lemon balm and oxazepam both calm the nervous system through overlapping pathways. Combining them may mean stronger drowsiness, slower reaction time, and a heavier morning grogginess than either tends to give on its own. Use with care, particularly around driving.

PMID 39683592 · PMID 29908682 · BNF: Oxazepam
Amber Temazepam

Lemon balm and temazepam both calm the nervous system through overlapping pathways. Both are taken to help with sleep, so combining them may mean deeper-than-intended sedation and a heavier morning grogginess.

PMID 39683592 · PMID 29908682 · BNF: Temazepam
Amber Zaleplon

Lemon balm has a mild calming, sleep-promoting effect, so taking it with zaleplon can add to the sedation and leave you groggier than intended. Use with care, particularly around driving the next morning.

PMID 39683592 · PMID 29908682 · BNF: Zaleplon

Lemon balm and zolpidem both calm the nervous system through overlapping pathways. Both are taken for sleep, so combining them may mean deeper-than-intended sedation and a heavier morning grogginess. Take care around driving the next morning.

PMID 39683592 · PMID 29908682 · BNF: Zolpidem
Amber Zopiclone

Lemon balm and zopiclone both calm the nervous system through overlapping pathways. Both are taken for sleep, so combining them may mean deeper-than-intended sedation and a heavier morning grogginess. Take care around driving the next morning.

PMID 39683592 · PMID 29908682 · BNF: Zopiclone

Reduced thyroid-hormone effect

Lemon balm has been shown in laboratory studies to dampen the thyroid-stimulating signal, so in theory it could work against your thyroid medication and let some underactive-thyroid symptoms creep back. This has only been seen in the test tube, not in people taking levothyroxine, so it is a precaution rather than a proven problem. If you want to take lemon balm regularly, mention it to the clinician who manages your thyroid and ask for a TSH check a few weeks later so your dose can be reviewed if needed.

PMID 6745167 · PMID 2985357 · BNF: Levothyroxine

Reviewer-flagged: awaiting clinical-reviewer sign-off.

What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope. Use the checker below to surface any medication, and submit a missing item if you take something we have not catalogued.

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