1-Deoxynojirimycin (DNJ) is a naturally occurring iminosugar, primarily found in mulberry leaves (Morus alba). DNJ is best known as a potent alpha-glucosidase inhibitor, meaning it slows down the breakdown of carbohydrates into glucose in the digestive tract. This results in a blunted postprandial (after-meal) rise in blood sugar levels. The primary scientific evidence for its use focuses on blood sugar management, particularly in the context of type 2 diabetes and metabolic syndrome, rather than specifically addressing "sugar cravings."

There is limited but suggestive evidence that DNJ may help reduce sugar cravings indirectly by stabilizing blood glucose and preventing rapid spikes and crashes that can trigger cravings. Some animal and preliminary human studies have shown that mulberry leaf extracts containing DNJ reduce post-meal blood glucose and insulin levels. However, direct studies on DNJ's impact on subjective sugar cravings in humans are sparse. Most clinical trials use endpoints such as glycemic control rather than craving intensity or frequency.

In summary, while DNJ has a scientifically validated effect on carbohydrate digestion and glycemic response, its use for the treatment or support of sugar cravings is only weakly supported and mostly extrapolated from its effects on blood sugar control. The direct evidence for craving reduction in humans is limited, so the evidence rating is modest.