D-Mannose

Also known as: mannose

Grade B — Moderate Evidencesugarurinary
1500–2000 mgTwice daily, or as prophylaxis

D-Mannose is a simple sugar that is minimally metabolized and excreted primarily through the kidneys, where it interferes with E. coli adhesion to urinary tract walls. Clinical trials demonstrate effectiveness comparable to antibiotics for preventing recurrent urinary tract infections (UTIs), with significantly fewer side effects. It works by competitively binding to the FimH adhesin on E. coli, preventing the bacteria from attaching to uroepithelial cells.

TL;DR: Natural sugar that prevents E. coli from adhering to urinary tract walls. As effective as low-dose antibiotics for preventing recurrent UTIs with far fewer side effects. Very safe and well-tolerated.

🛡️Immunity🦠Gut Health
Last reviewed: 2026-03-12

Quick Facts

Evidence

Grade B

Studies

2

Interactions

1

Forms

1

Evidence Rating: Grade B — Moderate Evidence

Some RCTs with positive results, or strong observational evidence. More research may refine our understanding.

Interaction Warnings

Diabetes medicationsLow

D-mannose is a sugar but poorly absorbed — minimal blood sugar impact. Still monitor if diabetic.

Important Notes

  • Primarily studied for E. coli UTIs only — not effective against all bacterial strains
  • Works by preventing E. coli from adhering to urinary tract walls
  • Very safe profile — a natural sugar found in cranberries and other fruits

Clinical Evidence (2 studies)

D-mannose vs antibiotics for recurrent UTIs

Kranjcec B et al. (2014) — World J Urol

D-mannose 2g/day was as effective as nitrofurantoin in preventing recurrent UTIs with significantly fewer side effects

View on PubMed

D-mannose for UTI prevention: pilot study

Porru D et al. (2014) — J Clin Urol

D-mannose 1g three times daily during acute UTI followed by 1g twice daily reduced recurrence rate by 80%

View on PubMed

Alternatives to Consider

These supplements target similar goals and may be worth considering alongside or instead of D-Mannose.

Cranberry Extract

Grade B

Concentrated source of proanthocyanidins (PACs) that prevent bacterial adhesion to urinary tract walls. Good evidence for preventing recurrent UTIs in women. Extract form (36mg PAC) is more effective and practical than juice. Safe for long-term use.

🛡️ Immunity🦠 Gut Health

Related Supplements

Cranberry Extract

Grade B — Moderate Evidence

Concentrated source of proanthocyanidins (PACs) that prevent bacterial adhesion to urinary tract walls. Good evidence for preventing recurrent UTIs in women. Extract form (36mg PAC) is more effective and practical than juice. Safe for long-term use.

NAC (N-Acetyl Cysteine)

Grade B — Moderate Evidence

Precursor to glutathione (master antioxidant). Strong evidence for respiratory health, liver support, and psychiatric conditions.

Probiotics

Grade B — Moderate Evidence

Beneficial bacteria for gut health. Strain selection matters — L. rhamnosus GG, B. infantis 35624, and S. boulardii are best-studied.

Sulforaphane

Grade B — Moderate Evidence

Powerful Nrf2 activator from cruciferous vegetables. Evidence for air pollution detoxification and H. pylori eradication.

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⚕️ Important Disclaimer

This information is for educational purposes only. It is not medical advice. Always consult a healthcare provider before starting any supplement regimen, especially if you take medications or have health conditions.

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