This simple sugar is a relative of glucose and is found in limited quantities in certain fruits and within the human body. It is usually taken as a supplement hopes to improve urinary tract health, especially if someone suffers from recurrent infections. Further investigation into its efficacy at the current time remains rather mixed: the largest recent trial found no definitive preventive benefit.
This is not a treatment for someone with an active infection, and should never replace medical care or the use of antibiotics when recommended by your clinician.
What Is This Sugar?
It is a monopolar, meaning it is a single molecule of sugar much the same as glucose but processed differently by the body. Trace amounts are found in cranberries, apples and some other plants. The body naturally also produces minute levels independently along the way.
As a powder or capsule, most of the dose is absorbed and then quickly renally excreted in the urine. It also is one of the factors that have caused researchers to investigate whether it can help with urinary tract problems.
It differs from table sugar and from cranberry products, which rely on other compounds.
Common Reasons People Take It
The majority purchase the supplement for prevention of repeat urinary tract infections, especially those associated with E. coli.
Doctors use it under strict conditions to treat a rare genetic disorder known as mannose phosphate isomerase–congenital disorder of glycosylation (or MPI-CDG). In this disorder, the sugar can circumvent an absent enzyme and ameliorate some of the metabolic defects. This type of medical use is completely unrelated to everyday dietary supplementation for the relief of bladder symptoms.
Other claimed benefits, such as general gut or immune support, rest on very limited evidence.
Research on Urinary Tract Infections
How the mechanism is thought to work
The majority of simple urinary tract infections in females are caused by E. coli. These bacteria use hair-like appendages capped with the protein FimH to latch onto cells lining the bladder. Free forms of this sugar can bind to that FimH protein, as demonstrated in laboratory and animal studies. If the bacteria stick to the sugar and not the bladder wall, it is much easier for your body to get rid of them when you urinate. The mechanism seems plausible but what is a laboratory finding does not easily transfer into benefits in people.
What the main studies found
The 2014 open-label study involved 308 women with recurrent infections. This randomized controlled trial compared 2 g per day of the supplement with low-dose nitrofurantoin or no prevention for six months. Overall, the repeat infections occurred in about 15 percent of those who were given supplements, 20 percent in the antibiotic group and 61 percent among those receiving no preventive treatment. The sugar offered milder side effects than the antibiotic. The study was not a high-quality type with respect to the results due to lack of placebo and blinding, however.
A 2022 Cochrane review looked at the trial data and found scant reliable evidence about whether the supplement can prevent or treat these infections. Reviewers assessed the certainty of the evidence as very low due to small sample sizes, methodological limitations and imprecision.
Published in JAMA Internal Medicine, a new trial of even larger scale and higher rigor (and also conducted by researchers from the USand not everyone else) than those previously examined this question more carefully in 2024. In UK primary care, researchers randomized 582 women with recurrent infections to either 2 grams daily (by dilute powder sachet) or a matching placebo for six months. Of this group, 51 percent of the supplement group and 56 percent of the placebo group sought care for a suspected new infection. These differences were not statistically significant. No advantage was shown by secondary outcomes: confirmed infections, antibiotic courses and symptom days. As such, the authors concluded that clinicians should not suggest giving the daily supplement for prevention in this population.
Subsequent meta-analyses have largely reaffirmed these findings — incorporating data in 2024, showing no consistent reduction in recurrent infections.
Where the evidence currently stands
Earlier smaller studies looked promising. More rigorously designed research has failed to demonstrate a clinically significant benefit. While the traditional evidence is currently scarce and contradictory at best, it does not yet support its routine use in preventing recurrent infections. The evidence for the treatment of an active infection is weaker still.
Dosage Amounts Used in Research
There is no official dosage: the evidence simply isn’t strong enough for one to exist. For the predominant trial designs (those aiming to prevent the return of colorectal cancer), 2 g was administered once daily (most commonly in powder form mixed with water). Similarly, other smaller studies tried higher or more frequent dosing if symptoms arose, but these arbitrary methods have little rigorous support.
Product labels vary widely. For those looking into the supplement, “If you have diabetes, have any problems with your kidneys or urinary tract and get infections a lot try to speak with the clinician about how much and for how long it is taken. They can also cause upset stomach, and larger doses do not necessarily result in more clinical efficacy.
Reported Side Effects
And most can tolerate a short period of use well enough. Common side effects are due to the gastrointestinal tract: diarrhea, loose stools or soft stools, gas and nausea. In the 2014 trial, about >8 percent of people taking 2 grams a day reported diarrhoea.
Serious problems linked to the supplement have been rare in published studies. Researchers have less information about continuous use beyond roughly six months.
Safety Points to Consider
Most healthy adults can safely use on a short term basis at the doses researched. Several groups need extra caution:
- Pregnant or breastfeeding people should avoid it unless a doctor specifically recommends it for a medical reason, because safety data are insufficient.
- Children should not take it outside of rare metabolic conditions managed by specialists.
- People with diabetes should check with their clinician and monitor blood sugar, since it is still a sugar.
- Anyone with kidney disease should get medical advice first, because the body clears the compound through the kidneys.
Supplement quality can differ between brands. Choosing products from companies that use third-party testing adds a layer of reassurance.
Who Needs Medical Advice First
It may be best to consult with a clinician before starting the supplement for those who are: suffering recurring urinary symptoms, have a history of complex or complicated infections, kidney stones, structural abnormalities in the urinary tract and diabetes with impaired renal function or individuals on concomitant medications. The recurrent infections often signify some underlying issue that should be correctly assessed rather than merely treated again like before.
When Symptoms Require a Doctor
Management should not be deferred in case of development of new urinary symptoms or exacerbation of previous ones. Painful urination, urgency, frequency blood in the urine lower abdominal or back pain fever and chills then call a doctor! Other clinical criteria include frequent infections (more than two in six months, or three or more in a year.
Antibiotics are never replaced by the supplement when there is a bacterial infection. If appropriate care is not sought soon enough, a possible bladder infection could spread to the kidneys.
Common Questions
What is this sugar?
A simple sugar related to glucose. It occurs naturally in small amounts in some fruits and in the body, and manufacturers sell it as a dietary supplement.
What do people mainly use it for?
Most take it hoping to reduce recurrent urinary tract infections. Doctors also prescribe it under supervision for a rare genetic metabolic disorder.
Does it help with these infections?
The best current evidence does not show a meaningful preventive effect. Earlier smaller studies looked more positive, but the largest placebo-controlled trial found no significant benefit.
How might it work against bacteria?
It may bind to a protein on certain E. coli strains and make it harder for the bacteria to stick to the bladder wall, so the body can flush them out more easily.
What amounts appear in the studies?
Most prevention trials used about 2 grams once a day. No established standard dose exists for general use.
What side effects can occur?
Mild digestive symptoms such as loose stools or bloating occur in a minority of users.
Is daily use safe long-term?
Short-term use up to about six months looks reasonably safe for most healthy adults. Longer-term data remain limited.
Can it replace antibiotics?
No. Antibiotics remain the standard treatment when a clinician diagnoses a bacterial infection.
Disclaimer: This article provides only general information This is not medical advice and it does not take the place of seeing a qualified health professional. Those interested in the supplement particularly those with persistent urinary issues, diabetes, renal conditions or who are pregnant or nursing ought to converse with their clinician before use.