Suspected UTI over 6 months: 51.0% D-mannose vs 55.7% placebo; not a significant difference
Hayward 2024, JAMA Intern Med · 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. We pair it with cranberry, which has stronger research behind it, rather than relying on it alone.
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 tested in the lab
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
Recurrence vs placebo: relative risk 0.23; vs antibiotics: 0.39, not significant
Lenger 2020, Am J Obstet Gynecol · Source
Recurrence over 6 months: 14% D-mannose, 20% nitrofurantoin, 60% no prevention
Kranjčec 2014, World J Urol · Source
Recurrence over 6 months: 4.5% with D-mannose vs 33.3% without
Domenici 2016, Eur Rev Med Pharmacol Sci · Source
How has it been used traditionally?
D-mannose is a sugar, not an herb, so it has no herbal monograph. European urology guidelines (2025) note the 2024 trial and don't yet recommend it on its own.
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