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ingestible · for urinary health & uti prevention

D-Mannose

Reviewed by the Nimbera editorial team · Last updated May 2026

Kranjcec 2014 World J Urol (PMID 23633128) - RCT of 308 women found recurrent UTI in only 14.6% of the D-mannose group versus 60.8% in the no-prophylaxis control group over 6 months (2 g/day). A 2024 JAMA Intern Med RCT (Hayward 2024, PMID 38587819) of 598 women found no statistically significant benefit (51.0% UTI vs 55.7% placebo, p=0.26), tempering earlier optimism.$15-$30/month for 2 g/day dosing

How to use

Take 2 g D-mannose powder dissolved in water once daily as ongoing prophylaxis, or 1.5-2 g every 2-3 hours for 2 days at the first sign of UTI symptoms (acute protocol from Kranjcec trial). Use consistently for at least 6 months to assess benefit. Drink a full glass of water with each dose.

How it works

D-mannose is a simple sugar absorbed from the gut, filtered by the kidneys, and excreted into urine in high concentrations. E. coli strains bearing type 1 fimbriae (FimH lectins) bind preferentially to mannose residues. When urinary mannose concentrations are high, the bacteria bind to free mannose molecules in urine rather than to mannose receptors on bladder epithelial cells, enabling them to be flushed out during urination.

Where to buy

NOW Foods D-Mannose Powder, Solaray D-Mannose, Life Extension D-Mannose, Doctor's Best D-Mannose with CranActin. Available at Whole Foods, iHerb, Amazon, and Vitacost. Powder forms allow flexible dosing.

Typical cost: $15-$30/month for 2 g/day dosing

Safety notes

The major 2024 JAMA Intern Med RCT found no significant UTI reduction versus placebo in a community setting, so effect size may be modest or limited to specific populations. D-mannose is a sugar - people with diabetes or G6PD deficiency should use caution and monitor blood sugar. No significant drug interactions identified to date. Safety in pregnancy is not well established - avoid unless directed by a physician. Do not use as a replacement for antibiotic treatment of a confirmed, symptomatic UTI.

Drug & supplement interactions

  • Always tell your doctor or pharmacist about any supplements you take.
  • Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
  • Herbal remedies can affect how the body absorbs or metabolises drugs.
  • Check drugs.com interactions checker before starting.

Clinical source

Kranjcec 2014 - World J Urol (PMID 23633128)

This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.