Does lemon balm repel mosquitoes, help cold sores, and work for anxiety? There are many health benefits like that claimed, though the studies behind them have not validated all those. What testing has confirmed is that the leaf's ORAC value - a measure of their antioxidant content - is moderately high.
ORAC Source
USDA Database for the Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods, Release 2 - Prepared by Nutrient Data Laboratory, Beltsville Human Nutrition Research Center (BHNRC), Agricultural Research Service (ARS), U.S. Department of Agriculture (USDA) - May 2010