Supplement Insider Evidence-based wellness
Ingredients/D-mannose
Moderate evidence overall reviewed 16 Sep 2026

D-Mannose

A simple sugar related to glucose

Works through a genuinely different mechanism from cranberry — blocking bacteria from sticking to the bladder wall rather than acidifying urine — with small but repeated positive trials for UTI prevention.

What the evidence supports

Moderate Recurrent UTI prevention Small randomised trials show recurrence rates comparable to low-dose prophylactic antibiotics in some studies, with fewer side effects.
Limited Treating an active infection Not studied or intended as a treatment — this is a prevention ingredient only.
Dose used in trials
1–2 g

per day for prevention, sometimes with a higher loading dose in the first days.

Safety
Very well tolerated

Mild GI upset at higher doses; generally one of the better-tolerated ingredients in any category.

See a doctor if
Active symptoms

Burning, urgency, cloudy urine or fever need prompt medical evaluation, not a supplement.

Related reading

Urinary health
The full urinary-health evidence guide
Product review
Urovance pairs D-mannose with cranberry