Medically Reviewed by Melinda Ratini, MS, DO on April 26, 2022
2 min read

D-mannose is a simple sugar found in many fruits. It is related to glucose. It also occurs naturally in some cells in the human body.

Other names for D-mannose are:

  • Carubinose
  • D-manosa
  • Mannose
  • Seminose

D-mannose is used to treat a rare disease called carbohydrate-deficient glycoprotein syndrome type 1b.

This disease is passed down through families. It makes you lose protein through the intestines. Some reports say D-mannose slows down this protein loss and makes your liver work better. It may also reduce bleeding disorders and low blood sugar in people with this disease.

Preliminary clinical trials in the U.S. and Europe show that D-mannose may also treat or prevent urinary tract infections (UTIs). Research suggests the supplement stops certain bacteria from sticking to the bladder walls. Scientists think that the bacteria stick to the sugar instead. This helps the bacteria leave the body through your urine. Fewer bacteria in the bladder lowers your risk of a urinary tract infection.  

Some studies suggest D-mannose may play a useful role as a "prebiotic." Prebiotics are substances that may help your body by stimulating the growth of "good" bacteria in your digestive system.

In some lab studies and studies in mice, D-mannose components were shown to increase the growth of "good" bacteria. This suggests D-mannose may have some use for people with dysbiosis, an imbalance in good and bad bacteria.

D-mannose supplements are taken by mouth.

D-mannose is found naturally in high amounts in many fruits. Such fruits include:

  • Apples
  • Oranges
  • Peaches
  • Some berries such as blueberries and cranberries

D-mannose appears to be generally well tolerated in people.

You should be cautious about using D-mannose if you are pregnant or breastfeeding, because there has not been enough study on its safety in these circumstances.

Side effects of D-mannose may include:

D-mannose supplements should be used with caution if you have diabetes. It may make it harder to control your blood sugar.

High doses of D-mannose may cause kidney damage.

Always tell your doctor about any supplements you are taking, including natural ones and those bought without a prescription. That way, your doctor can check on any potential side effects or interactions with any medications.

Supplements are not regulated by the FDA the same way that medications are. They do not have to prove they are safe or effective.