D-Mannose doesn’t work, am I resistant to D-Mannose?

Is it possible that all over sudden D-Mannose doesn’t work for you? Especially if it seemed to work before?

I’ve seen several D-Mannose fans mentioning that the powder stopped working for them or they need to consume much bigger doses to make it work, which begs the questions: can you become resistant to D-Mannose?

To answer this, we need to review how D-Mannose works and how resistance is developed.

#1 Here is how D-Mannose works (when it does) under microscope

In case if you are not familiar with a general concept of how E. coli interacts with D-Mannose, this is a primer for you: What’s D-Mannose and how does it work. This post will explain that E. coli could attach itself to D-Mannose and therefore is washed away from your bladder with urine.

But how exactly E. coli attaches itself  D-Mannose? Let’s zoom in.
E. coli bacteria can express so called “pili” (they are like tiny hairs sticking out of bacterias’ bodies). E. coli can potentially grow up to 16 different types of those hair-like appendages. However, there is only one type that “grabs on” to mannose (either the one on your bladder wall or D-Mannose in your urine).

Unfortunately, scientists do not know what makes E. coli to grow one type of pili versus another.

Fortunately, most of the harmful E. coli types that cause repeated UTIs grows that particular pili that we need in order for D-Mannose to work. But again, nobody knows why. As you can see, there is already plenty of room to speculate why D-Mannose doesn’t work for you but works for somebody else.

#2 Here is how bacterial resistance happens

If you have developed an acute bladder infection, it means that pathogenic bacteria are present in your bladder.

Now, when you drink an antibiotic, let’s imagine it will kill 99% of bad bacteria. However, 1% that remained alive due to genetic mutation had some properties that allowed those bacteria to survive.

Next, the survivors will pass on their genes and reproduce to create more bacteria with the advantageous (to them) properties. Therefore, the next generation becomes resistant to the antibiotic that has been used on their parents (if the parents survived, of course). It is basic natural selection at play: we kill “weak” ones and the “strongest” survive.

#3 Possible reasons why D-Mannose doesn’t work

First of all, D-Mannose does not kill bacteria at all, which is a good thing. So it is theoretically impossible to develop resistance to D-Mannose.

Imagine, you have bunch of harmful bacteria stuck to your bladder walls, you throw in D-Mannose, they stuck to the sugar instead, and are washed out while you are peeing.


a) D-Mannose forms a pretty weak bond with E. coli, so it could happen that some bacteria “unstick” from the sugar and remain in the bladder to reproduce.

b) Theoretically it is possible that some of your E. coli might not express the pili that is needed for them to stick to mannose. However, in that case they, perhaps, are not going to be able to stick to your bladder walls either.

But other factors could complicate the situation and make it harder to eliminate harmful bacteria, which would seem to you as though D-Mannose doesn’t work anymore.

Here are options why:

  • Every UTI instance damages your bladder lining. Damaged bladder lining provides more “hiding” space for bacteria and it becomes harder and harder to completely get rid of it.
  • Bacteria can form biofilms, that make the bacteria “stronger” and harder to eliminate.
  • There could be multiple pathogenic bacteria types present, and only E. coli reacts to D-Mannose.
  • You might not even have an infection and that’s your bladder “phantom pains” due to repeated lining damage. In that case D-Mannose obviously won’t work
  • Some say D-Mannose irritated their bladder. Perhaps instead of “resistance” you are becoming allergic to D-Mannose and this is bladder irritation, not UTI symptoms?

Back to you: what are your thoughts? Does the magic powder work for you or not any more?




  1. Anastasia,
    This article is very informative, thank you! I just wanted to make sure I understand it in terms of my situation. I dealt with reacurring uti’s from sex for about 4 years, about once every 3 to 4 weeks. When I started taking d mannose after sex it was a miracle. In the last year and a half I’ve only had 1 infection and I think it was because I waited too long after sex to take the d mannose. When I did get an infection that one time I tried taking d mannose every 2 hours to treat the infection. It didn’t work and I had to take antibiotics. But the d mannose has continued to work as a preventative since that one infection a year ago. Today, I forgot to take it after sex for a couple hours, similarly to the last infection, and fear that I’ll get an infection. I’m considering taking the d mannose throughout the whole day to prevent the infection but I don’t want risk creating an immunity to it, being that it didn’t work to treat an infection last time, but only works to prevent one. I see that theoretically I shouldn’t worry. Do you agree? It should I just let the infection develop to about risk of letting the ecoli learn how to about attaching itself to the d mannose? Thanks!

    • Sorry for the typos in that last sentence! Should I just let the infection develop to avoid the risk of letting the ecoli learn how to avoid attaching itself to the d mannose?

      • Hi Lindsey 🙂
        I think you shouldn’t worry and go ahead take it. Resistance is not built because bacteria learn how to react, but mostly because there are already bacteria that are not affected by whatever measure is tried on them, and then they are the only survivors who keep multiplying. Hope this makes sense! D-Mannose, unlike antibiotics, does not kill bacteria. There are multiple types of bacteria causing UTI, even multiple types of E. coli. But it’s believed that the pathogenic type of E.coli adheres to the bladder’s mannose with their hands called “pili”. So in the essence, if E. coli are already pathogenic (could cause a UTI) then they also should attach to D-Mannose. Did your physician office do a urine culture last time? Perhaps, this was a combo of pathogenic bacteria. I’d suggest adding some other antibacterials (supplements, herbs) to your routine and since your UTIs are “caused” by sex, also look at you vaginal health. You are welcome to join our FB group if you’d like to chat more!

  2. Hi
    I am dealing with proteus mirabilis. Most implements are designed to fight that. I have been on a broad spectrum antibiotic that didn’t knock it out even though it was sensitive to it. During the treatments I never felt healing. Here I am 6 days later burning. Urinalysis shows white blood cells but no infection. Since urinalysis, the symptoms are worse. I read a study that was done in 2012 where scientists tested cranberry powder on Ecoli and proteus mirabilis because they are both gram negative. They said it worked to disable them from swarming because it hindered the flagella. My question is do you think that d mannose could possibly help in my situation? Do you know of any supplements that could possibly hinder proteus mirabilis ? I do not want to go on antibiotics again.

    • Hi Trenika,
      Sorry, sounds exhausting!
      However, I’m confused why they prescribe you antibiotics as per your comment “Urinalysis shows white blood cells but no infection”? You mean they did a culture test and it shows no bacterial growth? Also, have you had cystoscopy?
      If no culture in urine, did you try asking your doctor for NSAIDs? Especially if the only symptom is burning I highly recommend looking for a second opinion rather than sticking with the doc who prescribes antibiotics when no active infection is detected. I’m not a doctor but if I were you I’d ask the physician if I could take Ibuprofen, changed my diet and focus on healing the bladder. I’d also see either a naturopathic or a homeopathic doctor.

      If you keep still taking antibiotics right now, see this post about biofilms . Also, this one and this one.

      Best of luck! You can also join our FB group that I just started to stay in touch.

  3. Dear Anastasia,

    I have been having recurrent UTI for 3 years. Then, after all kinds of tests, which did not show any abnormalities, urodynamics showed that I had pelvic floor dysfunction and my doctor suggested that it could have been the potential cause for UTI (I posted this somewhere else too).
    After treating that dysfunction I had been taking D-mannose twice a day as a preventative method for half a year. Recently I again had UTI again, so there was a 1-year gap between the last and current UTIs.
    During this one year, I changed a lot of things in my life (diet, hygiene habits etc), which may have also helped to prevent UTI.

    My question is that how can I understand whether D-mannose works for me or not?

    During this last UTI, when it just started, I started taking D-mannose immediately, 2-3 times a day, until my culture test results came. But it did not alleviate the burning in urethra, as in other topics it was described to help reduce the symptoms. On day 4 my felt that I started having cystitis and luckily my doctor prescribed the antibiotics so I just took them.

    So, does this mean that D-mannose did not help me or it could be helped a bit?
    How to figure this out?


    • Hello,

      Yep, I remember your earlier post.
      When I spoke to scientists in Washington School of Medicine who head the research in mannosides they couldn’t answer this question. Simply put, for some D-Mannose works, for others it doesn’t work. We do not know why. It seems like they have narrowed down the type of E. coli that causes UTIs to also be capable of binding to D-Mannose, but perhaps there are other versions of E.coli that don’t. We don’t know! Also, the more often you have UTIs, the higher your chances that a new infection is caused by a combination of bacteria (E. coli and Klebsiella, for example). I, personally (and I’m not a physician so this is not a medical advice, just one random girl’s opinion) would take D-mannose preventively or even together with antibiotics if there are no side-effects. I would also add other antibacterials and definitely NACs. Also, anything that could help to bring down the inflammation (ask your doctor about NSAIDs, cornsilk, and marshmallow tea etc..). And I would also double-down on probiotics for vaginal health.
      Think back, where there any other out of ordinary things happening in your life before your last UTI? Too much stress? Poor diet? Too much sex? New lube? etc… see if this could help you to pin down the issue further.
      What about your vaginal health? Any BV or yeast infection recently?

      Best wishes,

      • Dear Anastasia,

        This is Seda, thank you so much for your reply. I am a research technician and I understand how variable and unpredictable E. coli can be. So it completely makes sense that D-mannose could not be an anodyne for any kind of E. coli caused infection.
        My infections so far were caused only by E. coli, as the lab tests showed, however, the strains were different. Particularly, the E. coli that used to cause UTI more than a year ago, seemed to have had mutated over the time since it was resistant to some antibiotics and I took Levofloxacin (strong antibiotic) in the end (when I end up having a kidney infection as well).
        However, current UTI strain did not have any resistance, so it seems to me that this pathogen was not the remaining/surviving/latent one from the old infection but a new E. coli that managed to enter the bladder recently.
        I have not heard about NACs and other things you listed above, I will do some research on them.
        However, I realized that none of my doctors ever mentioned that vaginal microflora is as important to maintain in a good shape as your immune system. So reading some posts on this website I thought it is definitely a good idea to reinforce vaginal health as well, I started taking probiotics, suggested here.
        Regarding habits changes since last UTI, I can’t think of anything, except for I stopped taking D-mannose after 6 months of taking. Then for another half a year I was fine. The recent UTI started when after intercourse I did not go to the restroom, as usual. So either, there already was a slowly developing infection and intercourse was just a kick to start UTI or my bladder has become very susceptible to even a small amount of bacteria. In this case (intercourse) bacteria maybe even didn’t interact with vaginal flora long enough to be attacked by it, or maybe the microflora was weak to kill those E.coli, I don’t know.

        Anyways, I finished my antibiotics now and I am again on D-mannose twice a day+probiotics…

          • Hello Seda, sorry for keeping you hanging. Here is a link to a post that I was writing, I think it would be helpful in your case. Bottom line, it is good that you started on probiotics and D-Mannose but it could be so that you need a little more than that. The link that I shared with you earlier explains types of supplements you might want to try to help your bladder heal and to fight the infection. The post that I just finished also helps to look at antibiotic therapy and recurrent infections from a new perspective.

  4. Hello, Anastasia!

    I found this blog just in time, because I was already thinking to something similar! I am currently taking D-mannose and trying to keep track on how things develop. I would like to thank you for sharing all of this with us, you did incredible job! I wish, that official medicine were as fast flexible and well educated.
    I am still struggling with recurrent uti, it’s been 3 years, and I am 26 now. I also have mental health problems, so rUTI don’t make my life any easier. And from that perspective, I want to share with you next link regarding diagnostics.
    I am more then sure, that current tests in clinical practice, both dips and culture in many cases are not sensitive enough to detect bacteria, if it’s not in its full growth state. This issue is mostly due to the fact that those tests are mostly designed in order to detect first acute full-blown infection. But in case if recurrent or chronic slowly developing infection most of bacteria as you know will be either attached to the surface or hidden deeper in the bladder lining.
    Why it’s important to know exactly that you do have an infection? As I already mention, apart from my uti problem, I have depression. And it’s been quite often when I had my first symptoms and went to the clinic and my urine sample came back clean. However, I knew for sure if nothing is done I would have really bad infection in couple of weeks, which would make me almost non-functional. Once i was trying to get any possible information about treatment or testing from a doctor in the clinic – he was trying to convince me that there’s no infection if test is negative, and he was almost saying that it’s all in my head. Since I tend to find all the reasons of bad things happening to me in myself, it was really frustrating to learn it from a person who was supposed to help. I think that diagnostic procedures for rUTI should be changed to become more thorough. I am a biologist myself, although I am not specializing in bacteria, I have an idea of false negatives, and possible causes of them. Please, publish this link in your blog, so more people might become aware that it’s not only in their heads.

    Sorry for my English, I am not a native speaker.

    • Hi Aleksandra,
      My English is not perfect either 😉
      You are absolutely right, conventional tests are not 100% correct. The doctors, unfortunately, have to be mindful about antibiotic overuse and have to rely on what they have at their disposal, hence the reaction.
      There are plenty of things you could try for prevention besides D-Mannose, I would definitely suggest rethinking diet, take special probiotics and additional supplements for your bladder.
      Best of luck,

  5. I just stumbled upon your website today and have been spending hours reading it. Just want to say THANK YOU so much for the insightful information. I gain a lot of knowledge and understanding of my symptom reading it. Just ordered D-mannose and NAC. Finger crossed. Hope it helps!

    Anyway, keep up the good work. I’m sure a lot of people immensely benefit from it 🙂

  6. First of all, excuse me for my English as it is not my mother tongue. 🙂
    Concerning the problem of e.coli „hiding“ in the bladder lining and then reappearing to cause another UTI I read a book by a German urologist who recommends a combination of d mannose and forskolin (a plant extract). There is some information online but most of it is not very informative as far as UTIs are concerned.

    Forskolin is normally used as a natural diet supplement for athletes and wasn‘t analysed for its effects on UTI in a larger scale yet but… it‘s completely plant-based and can be purchased legally so I gave it a try. 😉

    Forskolin „kills“ the biofilm that enables the bacteria to hide in the bladder lining and flushes them back into the bladder. This is where the d mannose kicks in and (hopefully) flushes everything out. I tried this last fall and have had no problems with recurring UTIs ever since. I‘d say it‘s at least worth to keep an eye on this.

    Stay UTI-free! 🙂

  7. Great post….confirms much of what I’ve been trying to research! Happy to read that if bacteria is not binding to dmannose it likely will also have trouble holding on to the bladder wall. I asked my doctor to provide me a copy of the culture report in order to see exactly which kinds of bacteria are present. In the mean time I have Dr’s antibiotics in the fridge as a last resort. Dmannose continues to eliminate symptoms, day 8 or so…Taking it with less water and giving it time to bind before drinking more water seems to be working. blood in urine seems to be gone for the most part. It can all flare up so quickly again if I’m not consistent and watch my diet, sleep/stress etc. The explanations about bladder tissue damage and biofilms were also very enlightening. I hope to find a quality naturopath here in Toronto and work towards healing any damaged tissue. Thank you so much for your articles!!!

    • Hello!

      It’s nice to find someone around with the same issue. Did you manage to overcome your problem? I also live in Toronto.


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