Urological Health Bladder Health Urinary Tract Infections What Is D-Mannose? This supplement is said to prevent urinary tract infections By Cathy Wong Cathy Wong Facebook Twitter Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health. Learn about our editorial process Updated on August 11, 2022 Medically reviewed Verywell Health articles are reviewed by board-certified physicians and healthcare professionals. These medical reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Lana Butner, ND, LAc Medically reviewed by Lana Butner, ND, LAc Facebook LinkedIn Lana Butner, ND, LAc, is a board-certified naturopathic doctor and licensed acupuncturist in New York City. Learn about our Medical Expert Board Print Table of Contents View All Table of Contents What Is D-Mannose? Health Benefits Side Effects Dosage and Preparation What to Look For D-mannose is a type of sugar found in certain fruits and vegetables such as cranberries, cabbage, and tomatoes. D-mannose is also produced in the body from glucose, another form of sugar. D-mannose is also known as mannose. As a dietary supplement, it is sometimes used to prevent urinary tract infections (UTIs) or bladder inflammation (cystitis) from infections. Though more research is needed, preliminary studies suggest that it could be helpful when used alongside traditional treatment. This article will describe some preliminary studies that support the use of D-mannose, possible side effects, and what to look for in a supplement. Verywell / Jessica Olah What Is D-Mannose? D-mannose is a kind of sugar naturally found in some fruits and vegetables. Good dietary sources of D-mannose include: CranberriesBlack and red currantsPeachesGreen beansCabbageTomatoes D-mannose may have health benefits for people who experience frequent urinary tract infections (UTIs), but more scientific evidence is needed. D-Mannose Health Benefits A number of small studies have suggested that D-mannose may help keep E. coli —the bacteria responsible for the vast majority of UTIs—from sticking to the cells lining the urinary tract. It is possible that this could help prevent and treat UTIs, but more research is needed. Frequent UTIs are usually treated with a low-dose antibiotic taken for six months or longer. While this may be effective, it can lead to antibiotic resistance. Antibiotic resistance occurs when an antibiotic is used often enough that the bacteria it's intended to kill become resistant to the medication, making it ineffective. Given this possibility, and the fact that more than 7 million healthcare provider visits a year are due to this type of infection, having a non-antibiotic treatment option is appealing. Prevention A study published in the World Journal of Urology in 2014 examined the use of D-mannose to prevent returning urinary tract infections. After one week of initial treatment with antibiotics, 308 women with a history of recurrent UTIs took either D-mannose powder, the antibiotic nitrofurantoin, or nothing for six months. During this period, the rate of recurrent UTIs was significantly higher in women who took nothing compared to those who took D-mannose or the antibiotic. The study concluded that the risk of recurrence was the same for the supplement group as the antibiotic group. However, fewer side effects were reported with D-mannose compared to the antibiotic. The main one noted was diarrhea, which occurred in 8% of women taking D-mannose. During an Infection D-mannose has also been tested in people with active UTIs. A small study of 43 women published in 2016 found that D-mannose taken twice daily for three days during an infection followed by once a day for 10 days resulted in a significant improvement in symptoms, UTI resolution, and quality of life. Those who received D-mannose for six months following treatment had a lower rate of recurrence than those who took nothing. Although D-mannose shows promise in these preliminary studies, a review published in 2015 concluded that there is a lack of strong evidence that D-mannose—and other remedies like cranberry juice and vitamin C—should be used as a replacement for antibiotics in treating UTIs. Research is ongoing and more studies are needed. Recap Preliminary research suggests that taking D-mannose may help prevent or treat UTIs in those with recurrent infections. However, studies are not large enough to support using D-mannose as a replacement for antibiotics. FDA Allows for Health Claims About Cranberries and UTI Prevention Possible Side Effects of D-Mannose Common side effects of D-mannose include: Bloating Loose stools Diarrhea As D-mannose exits the body in urine, there is also some concern that high doses may injure or impair the kidneys. Since D-mannose can alter your blood sugar levels, it's crucial for people with diabetes to take caution when using it. Not enough is known about the safety of the supplement during pregnancy or breastfeeding, so it should be avoided. Children shouldn't take D-mannose either. As a rule, self-treating a UTI with D-mannose or otherwise avoiding or delaying standard care is unadvised as it can lead to serious complications, including a kidney infection and even permanent kidney damage. Recap D-mannose supplements may cause bloating or loose stools and can alter blood sugar levels. At high doses, there may be serious risks such as kidney damage. Dosage and Preparation As a supplement, D-mannose is available as a powder or in capsule form. D-mannose powder is typically dissolved in liquid and taken as a drink. Little is known about the long-term safety of D-mannose or at what dose the supplement may be considered harmful or toxic. While D-mannose is typically considered safe because it occurs naturally in many foods, doses higher than what is consumed through a normal diet may pose unknown health problems; it's simply not known at this stage. Dosages as high as 2 grams daily to prevent UTIs and 3 grams to treat UTIs have been used in studies. Recap The optimal dosage of D-mannose and its long-term safety are still largely unknown. The amount taken in studies to prevent UTIs was up to 2 grams daily. What to Look For It's important to keep in mind that dietary supplements haven't been tested for safety and are largely unregulated in the United States. When shopping for supplements, look for products that have been certified by ConsumerLab, The U.S. Pharmacopeial Convention, or NSF International. These organizations don't guarantee a product is safe or effective, but their seal indicates that a supplement has undergone testing for quality. Recap If you decide to take D-mannose, look for supplements with certifications that indicate quality testing. Summary Preliminary studies suggest that D-mannose holds promise as a way to help prevent UTIs. However, larger high-quality studies are needed to confirm the findings and the safety of D-mannose supplements. If you're still thinking of trying D-mannose to prevent UTIs, talk with your healthcare provider first to weigh the pros and cons and decide whether it's a good option for you. 9 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Porru D, Parmigiani A, Tinelli C, et al. Oral D-mannose in recurrent urinary tract infections in women: a pilot study. Journal of Clinical Urology. 2014;7(3):208-213. doi:10.1177/2051415813518332 Scribano D, Sarshar M, Prezioso C, et al. D-mannose treatment neither affects uropathogenic escherichia coli properties nor induces stable FimH modifications. Molecules. 2020;25(2):316. doi:10.3390/molecules25020316 Ahmed H, Davies F, Francis N, Farewell D, Butler C, Paranjothy S. Long-term antibiotics for prevention of recurrent urinary tract infection in older adults: systematic review and meta-analysis of randomised trials. BMJ Open. 2017;7(5):e015233. doi:10.1136/bmjopen-2016-015233 Medina M, Castillo-Pino E. An introduction to the epidemiology and burden of urinary tract infections. Therapeutic Advances in Urology. 2019;11:175628721983217. doi:10.1177/1756287219832172 Kranjčec B, Papeš D, Altarac S. D-mannose powder for prophylaxis of recurrent urinary tract infections in women: a randomized clinical trial. World J Urol. 2014;32(1):79-84. doi:10.1007/s00345-013-1091-6 Domenici L, Monti M, Bracchi C, et al. D-mannose: a promising support for acute urinary tract infections in women. A pilot study. Eur Rev Med Pharmacol Sci. 2016;20(13):2920-5. Aydin A, Ahmed K, Zaman I, Khan MS, Dasgupta P. Recurrent urinary tract infections in women. Int Urogynecol J. 2015;26(6):795-804. doi:10.1007/s00192-014-2569-5 Altarac S, Papeš D. Use of d-mannose in prophylaxis of recurrent urinary tract infections (UTIs) in women: Comment. BJU Int. 2014;113(1):9-10. doi:10.1111/bju.12492 NIH National Library of Medicine. D-mannose for the prevention of UTIs in multiple sclerosis. Editorial Process Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! 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