D-mannose vs other agents for recurrent urinary tract infection prevention in adult women: A systematic review and meta-analysis 

In 2020 a group of researchers investigated the evidence and validity of D-mannose use as an intervention or prophylactic treatment for recurrent urinary tract infections. Eight publications met eligibility. Relative risk of urinary tract infection recurrence comparing D-mannose to placebo was 0.23 (D-mannose n=125, placebo n=123). Concluding that D-mannose is protective for UTI (versus placebo) in adult women with possibly similar effectiveness as antibiotic prophylaxis. 

References:

Lenger SM, Bradley MS, Thomas DA, Bertolet MH, Lowder JL, Sutcliffe S. D-mannose vs other agents for recurrent urinary tract infection prevention in adult women: a systematic review and meta-analysis. Am J Obstet Gynecol. 2020 Aug;223(2):265.e1-265.e13. doi: 10.1016/j.ajog.2020.05.048. Epub 2020 Jun 1. PMID: 32497610; PMCID: PMC7395894.