
Scientists first determined which parts of the mulberry plant, which planting locale and which harvest season -produced the most potent DNJ. Researchers then recruited healthy volunteers who took 6 mg, 12 mg or 18 mg of DNJ, or a placebo, followed by 50 grams of sugar.
After waiting 30 to 180 minutes, doctors measured blood-plasma levels of glucose and insulin and found that the 12 mg and 18 mg doses of DNJ significantly reduced after-meal glucose and insulin, concluding that DNJ can be effective in preventing diabetes mellitus.