D-mannose is one of those supplements often used for chronic urinary tract infections. While I’ve heard some very positive reviews about it, it never helped me back when I took it myself.
Therefore I wanted to examine the evidence behind D-mannose a bit closer to see how useful it actually is for those struggling with chronic UTIs.
What is D-mannose?
D-mannose is a simple sugar similar in structure to glucose and can be found naturally in some fruits (e.g. cranberries). Commercially it is usually extracted from larch rod.
D-mannose is a fine white powder that has a sweet pleasant taste and is widely available online.
D-mannose is also normally present in human metabolism.
The action of D-mannose on UTIs
D-mannose cannot be metabolized the same as regular sugars and is therefore safe to take for those who need or want to restrict sugar and it also seems to be safe to take long-term.
It is absorbed quickly and can reach the bladder in around 30 minutes after intake.
Its main supposed action is to prevent the adherence of UTI-causing pathogens to the bladder wall.
One main factor of developing an UTI is the adherence of the pathogens to the bladder wall. Pathogenic bacteria known to cause UTIs, such as E. coli, have the ability to attach themselves to certain molecules on the cells of the bladder lining (including our own D-mannose).
It has been suggested that supplemental D-mannose can be used to bind to those pathogens, thereby keeping them from attaching to the bladder wall and helping to carry them out of the body in urine.
Moreover, D-mannose may also have some beneficial effects on the regulation of the immune system  and a healthy immune system is vital for dealing with infections.
Evidence for using D-mannose
I’ve never had much success with using D-mannose myself, however there are some papers that do support its efficacy:
- One randomized clinical trial from 2014 on 308 women with a history of recurrent UTIs concluded that ‘D-mannose powder had significantly reduced the risk of recurrent UTI’ after 6 months and was just as effective in doing so as a prophylactic antibiotic .
- A study of 43 women with cystitis showed a marked improvement of symptoms in 15 days of taking D-mannose and it was suggested that D-mannose could be an effective aid for acute cystitis as well as prophylaxis .
- A small study in MS patients showed that D-mannose helped to decrease the number of monthly UTIs without causing any adverse effects .
How to use D-Mannose
The dosage used in clinical trials is around 2-3 g daily in water, ranging from 4-6 months.
There is no standardized recommendation on how much and how often to take it, but because it is deemed to be safe one could experiment a little bit with dosage and timing.
For acute UTIs, 500 mg every few hours may be a starting point.
D-mannose could be taken prophylactically at times when one is more prone to UTIs, for example just before intercourse, or generally over longer periods of time.
As you can see, on top of anecdotal evidence we also have some clinical evidence for the use of D-mannose.
But here is the caveat: it will only work on pathogens that have ‘mannose-sensitive adhesins’ i.e. that are equipped to attach to mannose. For example E. coli.
If the infection is caused by a bacteria that isn’t mannose sensitive, or the infection is fungal, D-mannose will be a waste of money.
So it may be worth a try, but I wouldn’t keep spending money on it if it doesn’t work out the first time.
I’d be interested to hear your experiences with D-mannose – has it helped? Let me know in the comments!
Pin it for later:
Michaels EK et al Effect of D-mannose and D-glucose on Escherichia coli bacteriuria in rats. Urol Res. 1983;11(2):97-102. https://www.ncbi.nlm.nih.gov/pubmed/6346629
Domenici, L. 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): 2920-2925
- Zhang, D. et al D-mannose induces regulatory T cells and suppresses immunopathology. Nat Med. 2017 Sep;23(9):1036-1045. doi: 10.1038/nm.4375. Epub 2017 Jul 24. https://www.ncbi.nlm.nih.gov/pubmed/28759052
- Kranjčec B et al D-mannose powder for prophylaxis of recurrent urinary tract infections in women: a randomized clinical trial. World J Urol. 2014 Feb;32(1):79-84. doi: 10.1007/s00345-013-1091-6. Epub 2013 Apr 30. https://www.ncbi.nlm.nih.gov/pubmed/23633128
- Domenici, L. 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): 2920-2925 https://www.europeanreview.org/article/11121
- Phé V et al Open label feasibility study evaluating D-mannose combined with home-based monitoring of suspected urinary tract infections in patients with multiple sclerosis. Neurourol Urodyn. 2017 Sep;36(7):1770-1775. doi: 10.1002/nau.23173. Epub 2016 Nov 4. https://www.ncbi.nlm.nih.gov/pubmed/27813195