✓ No active regulatory warningsFDA MedWatch, EMA EudraVigilance, WHO VigiBase, WADA Prohibited List · 2026-05-29
📰Read the full D-Mannose evidence review on GMJ News →Complete clinical article, references and updates on news.gmj.ge. This page is the structured safety summary.⚠ Acute UTI — D-mannose is NOT a substitute for antibiotics [2]
⚠ Only works against E. coli (type 1 fimbriae) — not Klebsiella, Proteus [1]
⚠ Does NOT affect blood glucose — safe in diabetes [1]
⚠ Comparable to nitrofurantoin prophylaxis in n=308 RCT [2]
ℹ️ Not obtained from food. Not applicable — this is not obtained from food in meaningful amounts; supplementation is the practical route.
🔬 Lab interpreter
Recommended test
Urine culture
Urine culture
Reference range / target
Negative for E. coli
Negative for E. coli
Confirm E. coli to predict D-mannose efficacy [1].
Full lab monitoring ↓⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
D-Mannose 2 g/day is comparable to prophylactic nitrofurantoin for preventing recurrent E. coli UTIs (n=308 RCT). NOT a treatment for acute UTI — antibiotics still needed. Works ONLY against E. coli (80–90% of uncomplicated UTIs). Does NOT raise blood glucose (excreted unchanged). Simple, sweet, well-tolerated [1] [2].
1 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: See guidance
Theoretically safe (natural sugar). Not specifically studied [1].
👦 Pediatric: See guidance
Limited data. Some case series in children with recurrent UTI [1].
🏃 Athletes: Standard dose
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose
How to take
🍽 Timing: Once daily prevention; TID for acute [2].
💊 With food: Dissolve in water. Sweet taste [1].
🚫 Avoid: Relying on D-mannose for acute complicated UTI [2].
2 Which form?
| Form | Bioavailability | Vegan | Cost |
|---|---|---|---|
| ['D-Mannose powder', 'preferred', 'Pure sugar. Sweet taste. Dissolves in water. 2 g per dose [1].'] | Standard | Check label | |
| ['D-Mannose capsules', 'common', '500–1,000 mg per capsule. Need 2–4 for therapeutic dose [1].'] | Standard | Check label |
3 Common questions
Is D-mannose as good as antibiotics for UTI prevention? ▼
The Kranjčec trial (n=308) found 2 g/day comparable to nitrofurantoin for preventing recurrence, with fewer side effects [2]. Not proven for TREATING acute UTI — antibiotics remain necessary for active infections.
Does it raise blood sugar? ▼
No — D-mannose is NOT metabolized like glucose. It is excreted unchanged in urine. It does not significantly affect blood glucose [1].
Does it work for all UTIs? ▼
Only for E. coli UTIs (80–90% of uncomplicated UTIs). E. coli uses type 1 fimbriae (FimH) to adhere to bladder cells — D-mannose blocks this. Non-E. coli UTIs (Klebsiella, Proteus, Enterococcus) are NOT affected [1].
Is D-mannose better than cranberry? ▼
Both target E. coli adhesion but through different mechanisms (D-mannose: FimH blockade; cranberry PACs: P-fimbriae). D-mannose has a stronger single trial (n=308) than most cranberry studies. They may be complementary [1].
4 Clinical evidence
Strong
Mechanism: D-mannose binds E. coli type 1 fimbriae FimH lectin — well-characterized molecular interaction [1]. Does NOT significantly affect blood glucose (not metabolized — excreted in urine) [1]. HIGH
Moderate
UTI prevention: RCT (n=308) showed D-mannose 2 g/day comparable to nitrofurantoin 50 mg/day for preventing recurrent UTI in women (36% vs 20% recurrence vs 60% no treatment) [2]. UTI treatment (acute): limited data — adjunctive only; NOT a substitute for antibiotics in complicated UTI [1]. MODERATE
Insufficient
5 Safety, toxicity & adverse events
Relative
⚠ Diabetes — it is a sugar and may affect glucose monitoring/control
⚠ Not a substitute for antibiotics in pyelonephritis or systemic infection
⚠ Pregnancy and lactation — limited data
🚩 Red flags
● Patient using D-mannose instead of antibiotics for acute pyelonephritis — dangerous; antibiotics needed [2]
● Non-E. coli UTI — D-mannose won't work [1]
6 Interactions
Supplement synergies
Cranberry · 500 mg cranberry extract
Different anti-adhesion mechanisms (FimH vs P-fimbriae). Complementary [1].
Different anti-adhesion mechanisms (FimH vs P-fimbriae). Complementary [1].
7 Regulatory
United States (FDA): Dietary supplement [1].
European Union: Food supplement [1].
8 US supplement products
7
on-market products containing D-Mannose (NIH DSLD)
Brands carrying D-Mannose (2)
Click a brand to see its D-Mannose products.
9 Cite this page
Vancouver: Pkhakadze G. D-Mannose — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Aug 15]. Available from: https://supplement.ge/ingredients/d-mannose/
APA 7th: Pkhakadze, G. (2026). D-Mannose — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/d-mannose/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Institution: Public Health Institute of Georgia (PHIG)
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: February 2027
References: 2 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "D-Mannose — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/d-mannose/ CC BY 4.0.
GP
Prof. G. Pkhakadze, MD, MPH, PhD
Professor of Public Health · Head of Department, DTMU
Editor-in-Chief, Georgian Medical Journal (ISSN 3088-4322)
Chair, Public Health Institute of Georgia · UEMS Public Health Section
Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG