D-mannose (or mannose) is a type of sugar found in a number of fruits and vegetables, including cranberries, black and red currants, peaches, green beans, cabbage, and tomatoes. It is related to the better-known glucose. These sugars are both simple sugars. That is, they consist of just one molecule of sugar. As well, both occur naturally in your body and are also found in some plants in the form of starch. Taking d-mannose in tablet form contains significantly more d-mannose than is naturally found in food, ensuring the recommended half teaspoon (approximately 1 gram) adult dose is reached. Very little of this simple sugar is metabolised. It doesn’t interfere with blood sugar regulation, even for diabetics.