Momordica charantia, commonly known as bitter melon or bitter gourd, has a long history of use as a culinary staple and a hypoglycemic agent in Southeast Asia. There is a plethora of botanical varieties recognized by native peoples, who differentiate between those good for eating and those good for medicine.
Animal studies consistently find blood-sugar regulating effects associated with certain varieties of bitter melon, including improvements in glucose tolerance and insulin sensitivity, especially when using freshly juiced or freshly extracted material. Despite significant investigation, the suite of important constituents responsible for the effects of bitter melon is poorly characterized. In fact, it is often found that creating extracts of bitter melon leads to a decrease in native activity.
A critical review of bitter melon research indicates that not only are some varieties preferred to others, but also that preparation methods play a significant role in overall activity and can explain large variations in reported dosing protocols. Neither the charantin nor the bitters components of bitter melon in published work have proven sufficient to explain the various benefits of fresh and freshly extracted bitter melon. Not everything labeled “bitter melon extract” is created equal.