In tropical areas from China, Asia, and Africa to the Caribbean and South America, bitter melon is both a food and a medicine. Unripe, its fruit resembles a warty, green cucumber that gradually turns orange with bright red edible seeds as it matures. Despite an exceedingly bitter taste, the fruits and sometimes the leaves are widely used in a variety of ethnic dishes. Bitter melon is a major constituent of the Okinawan diet and, some say, is key to the renowned longevity of the Japanese island people. Modern research has largely focused on its potential for treating diabetes.

How Bitter Melon Works

Although the human evidence is not yet strong, laboratory studies show that bitter melon has a hypoglycemic (blood glucose-lowering) action, and helps to control insulin levels. The constituents thought to be responsible for this action are charantin, plus alkaloids and peptides that mimic insulin. They may also trigger the production of a protein that encourages glucose uptake in the body.

In addition, charantin appears to stimulate the growth of pancreatic beta cells, which produce insulin. In type 1 diabetes, the immune system destroys beta cells; in other types of diabetes the functioning of beta cells is impaired.

Laboratory studies support other traditional uses of bitter melon, suggesting that different constituents have antiviral and antibacterial properties that might help to treat disorders including salmonella and E. coli infections, herpes and HIV viruses, malaria, and parasitic worms. An extract of bitter melon proteins is claimed to inhibit prostate tumor growth and a number of in vitro studies suggest it may have potential for combating other cancers and leukemia.

How to Use Bitter Melon

Traditionally bitter melon is taken as a fresh juice, decoction, or tincture. Concentrated fruit, seed, and whole herb extracts are also available as tablets, capsules, or powders. Follow label instructions or take as professionally prescribed.

Safety First

Take care if taking bitter melon with blood glucose–lowering medications as it can enhance their effect. It has a weak uterine stimulant activity so must not be used during pregnancy or breastfeeding. Bitter melon should not be taken by people with glucose-6- phosphate dehydrogenase (G6PDH) deficiency (a genetic condition most common in people from the Mediterranean and Middle East) due to a risk of hemolytic anemia.

Where to Find Bitter Melon

The fresh fruit is available in some supermarkets and Asian stores. Bitter melon supplements are available in health food stores or from a qualified herbalist.