Where Does Lemon Balm Have the Strongest Evidence?

Lemon balm has attracted particular clinical interest for sleep, anxiety and stress, although the strength of the evidence varies according to the preparation used.

In a small placebo-controlled study, a standardized lemon balm extract taken at night improved measures of insomnia and sleep quality. Another controlled trial involving people with type 2 diabetes and depression found improvements in depression and anxiety scores after taking lemon balm extract, although other outcomes such as blood pressure, sleep quality and blood glucose did not show significant differences.

There is also clinical evidence for a very different use: cold sores caused by herpes simplex virus. A standardized lemon balm extract cream applied directly to cold sores improved symptoms compared with placebo and was associated with faster relief of typical complaints such as itching, tingling and burning.

Lemon balm essential oil has mainly been studied through inhalation. Some trials suggest possible benefits for sleep quality and short-term stress responses, but results are less consistent than those for standardized extracts.