There aren’t any clinical reports of drug interactions with lemon balm. However, it has the following theoretical drug interactions:[1][2][3]
| Drug or class | Potential Interaction | Evidence |
|---|---|---|
| Sedatives | May increase sedation | Pre-clinical and initial human research |
| Barbiturates | May increase hypnotic (sleep-inducing) effect | Animal studies |
| Drugs that enhance or inhibit cholinergic activity | Binds to muscarinic and nicotinic receptors receptors (clinical relevance not determined and effect likely varied) | In vitro research[4] |
| Selective serotonin reuptake inhibitors (SSRIs) | May reduce effectiveness | In vitro research |
| Thyroid hormone replacement | May reduce effectiveness | In vitro and animal research |
Additionally, there’s in vitro evidence that one component of lemon balm, rosmarinic acid, may inhibit some of the enzymes also used to process drugs: cytochrome P450 (CYP450) enzymes CYP2C19 and CYP2E1, and UDP-glucuronosyltransferases (UGTs) UGT1A1, UGT1A6, and UGT2B7. This could theoretically affect the metabolism of any prescription drugs processed by these enzymes, although there have been no reports of this to date.[5][3]