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Long-Term Risks of D-Mannose Supplementation

D-Mannose is a popular supplement in the realm of bladder health. I had my intern review the current research and explain what the effect of D-Mannose is on the bladder and the safety of taking it long-term.

What is D-Mannose?

D-Mannose is a simple sugar that is related to glucose. It also occurs naturally in some cells of the body.

Other names for D-Mannose are:

● Carubinose ● D-manosa ● Mannose ● Seminose

D-Mannose is naturally found in fruits and berries such as:

● Apples ● Oranges ● Peaches ● Mangos ● Blueberries

● Cranberries

What Does D-Mannose Do?

Dietary supplements have been made since D-mannose is often proclaimed as a natural way to prevent urinary tract infections (UTI) or bladder inflammation (cystitis) from infections. Though more studies are needed , preliminary studies suggest that the supplement will be able to prevent certain bacteria from sticking to the walls of the urinary tract and causing infection.

How D-Mannose works is by sticking to the bacteria instead of the bacteria sticking to the bladder wall. Because it’s a sugar molecule, scientists believe that the bacteria will stick to the sugar instead. This helps the bacteria leave the body through the urine. Fewer bacteria in your bladder reduces your risk of urinary tract infections.

Since D-Mannose aids in urinary inflammation relief, it can be another over the counter medication for those with interstitial cystitis, but just like other over the counter medications, they are only used for temporary relief and are not meant to be used long term.

Can I take D-Mannose daily?

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.

Common side effects of D-mannose include: ● Bloating ● Loose stools

● Diarrhea

As D-Mannose exits the body through the urine, there is concern that taken in high doses can lead to kidney damage. Another important note, if an individual has diabetes, they should be cautious taking D-Mannose as it can alter blood sugar. Not enough is known about the supplement during pregnancy or breastfeeding so it would be best to avoid. The average amount taken for case studies was up to 2 grams daily.

It is important to remember that everybody’s body is different and some over the counter supplements can help some but not others. Always consult your doctor or dietitian about any supplements you are taking, even natural ones and those bought without a prescription. That way, your doctor and/or dietitian can check any potential side effects or interactions with medications.

If you are interested in trying D-Mannose, I love West Coast Mint's D-Mannose powder. Use code "CKN15" to get 15% off D-Mannose.


Ala-Jaakkola, R., Laitila, A., Ouwehand, A.C. et al. Role of D-mannose in urinary tract infections – a narrative review. Nutr J 21, 18 (2022).

Cox, A. et al. Management of Interstitial Cystitis/bladder Pain Syndrome. Can Urol Assoc J. 2018 Jun; 12(6 Suppl 3): S157–S160. doi: 10.5489/cuaj.5324

Hemphill, I. (2021). KHealth. Accessed April 2022. <>

Miller, K. (March 2020). WebMD. Accessed April 2022, < >

Wong, C. (Nov 2021). Verywellhealth. Accessed April 2022, < %2Dmannose%20supplements%20may%20cause,risks%20such%20as%20kidn ey%20damage.>

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