Recurrence over 6 months: 14% D-mannose, 20% nitrofurantoin, 60% no prevention
Kranjčec 2014, World J Urol · Source
D-Mannose
A natural fruit sugar
A simple sugar found in fruits like cranberries, and one of the most-discussed nutrients for urinary tract health. Researchers think it gives certain bacteria something to hold on to other than the bladder wall.
308women in an early six-month trial
7trials pooled in a 2022 Cochrane review
Naturala simple sugar found in cranberries
Why we love it
D-mannose is one of the most widely discussed nutrients for urinary tract health, and researchers think it works in a simple way: some bacteria grip a mannose sugar to stick to the bladder wall, so mannose in the urine may give them something else to hold on to.
What does the research show?
Early trials
In a 2014 trial of 308 women with recurrent UTIs, 14% of those taking 2 g of D-mannose daily had another infection over six months, compared with 20% taking a low-dose antibiotic and 60% taking nothing. A 2020 review pooling the early studies found about 77% fewer recurrences than placebo.
Where the evidence stands
The largest trial so far, 598 women in the UK in 2024, found no clear difference from placebo, and a 2022 Cochrane review rated the evidence as very low certainty. That's why we pair D-mannose with cranberry rather than relying on it alone.
Studies
Human study tested in people Lab study a starting point, not proof
Recurrence vs placebo: relative risk 0.23; vs antibiotics: 0.39, not significant
Lenger 2020, Am J Obstet Gynecol · Source
Recurrence over 6 months: 4.5% with D-mannose vs 33.3% without
Domenici 2016, Eur Rev Med Pharmacol Sci · Source
Suspected UTI over 6 months: 51.0% D-mannose vs 55.7% placebo; not a significant difference
Hayward 2024, JAMA Intern Med · Source
Not enough evidence to know whether D-mannose prevents or treats UTIs; side effects few and not serious
Cooper 2022, Cochrane Database Syst Rev · Source
Is D-mannose safe to take?
Large amounts can cause loose stools or bloating. Because it is a sugar, people managing blood sugar may want to check with their clinician. D-mannose is studied for prevention. If you have symptoms of a urinary tract infection, see a healthcare provider.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed: November 2026.
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Reviewed by the Momotaro Apotheca medical team, including OB-GYNs and naturopathic doctors. Educational information, not medical advice. All ingredient research