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D-Mannose: Your Ally for Urinary Health

D-Mannose: Your Ally for Urinary Health

Published: 27 May, 2024 | 4'

Did you know that there is a type of sugar that is very beneficial for your urinary well-being? D-mannose has been gaining popularity for its positive effects on the urinary tract and will become one of your best allies for its good condition throughout the year. We'll tell you about its origin and why it has traditionally been used in this field.

What is D-mannose?

D-mannose is a natural monosaccharide sugar that is found in our metabolism and has beneficial properties in the urinary tract. In three clinical studies1,6,7 conducted in women with urinary discomfort, the usefulness of D-mannose, either alone or in combination with cranberry, has been demonstrated in the relief of acute urinary discomfort within a period ranging from 5 to 10 days.

Natural origin

It is a type of simple sugar, very similar in structure to glucose, that is naturally present in some fruits such as cranberries, apples, and pears, although in very small amounts.

Action of D-mannose in the body

When ingesting this compound, our body is able to absorb at least 90% of D-mannose directly in the upper part of the intestine, so it enters the bloodstream. The duration of D-mannose in the blood ranges from 30 minutes to several hours, after which it is eliminated through urine. Generally, the compound is excreted unchanged in the urine after 30-60 minutes, with the rest being eliminated within the next 8 hours.

The role of D-mannose in the urinary tract

Urinary discomfort is very common in women, with annual episodes observed in at least 11% of women aged 18 and older, and this percentage increases with age due to functional conditions and anatomical changes.6

These discomforts are due, among other factors, to the adhesion of bacteria to the surface of the urinary tract. The bacteria with the highest prevalence is Escherichia coli, which is able to adhere to the lining of the urinary tract through the action of proteins on its bacterial surface called fimbriae.

Reduction of bacterial adhesion in the urinary tract

D-mannose is mainly eliminated through urine, and as it passes through the bladder, it adheres to its walls. D-mannose acts as a "decoy" since it mimics the lining of the bladder tissue, which "attracts" bacteria, creating an anti-adherent surface capable of binding to their fimbriae. This binding allows bacteria to be eliminated from the urinary tract5.

D-mannose and the microbiota 

The intestinal microbiota is the set of bacteria that live along our gastrointestinal tract, containing approximately 200 species and the main ones being Firmicutes and Bacteroidetes, which account for 75% of the total. There are various reasons why our intestinal microbiota can be altered, such as stress or an unbalanced diet, which leads to intestinal dysbiosis that directly affects overall health. Among the conditions that can affect our body's metabolism are weight fluctuations.

The intestinal microbiota obtains energy for its maintenance and for the functioning of our body in general through the fermentation of carbohydrates (including sugars). Depending on the type of sugar ingested in the diet, the metabolic activity is different. D-mannose is metabolized by the intestinal microbiota and promotes a good proportion of microorganisms (Firmicutes and Bacteroidetes), which generate short-chain fatty acids (e.g. propionate, butyrate), which participate in regulating the production and storage of sugars and fatty acids, and in appetite and satiety sensations. Some studies show that the activity of D-mannose promotes weight control3,4.

How is D-mannose taken as a supplement?


Since the amount of D-mannose we can obtain through diet is very low, we can find this compound in the form of dietary supplements to take advantage of its properties in different formats such as capsules or drinkable vials.

Generally, an intake of 500 milligrams to 2 grams of D-mannose for several days is sufficient to notice its benefits. Although relief from urinary discomfort can occur in as little as 24 hours in very mild cases, it is recommended to continue taking it for at least 5-10 days, according to the data from the studies.

D-mannose is usually presented in formulations along with other compounds that promote the well-being of the urinary tract, such as American cranberry or bearberry.

Tips for use

Being a naturally occurring monosaccharide, D-mannose has no reported adverse effects, although it is always recommended to follow the manufacturer's instructions when taking it as a dietary supplement and not to exceed the recommended daily intake.

In the case of taking it as a dietary supplement for its benefits in the urinary tract, it is advisable to consult a specialist professional if the discomfort persists for several days.

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Content reviewed by the specialists of the MARNYS Scientific Information department. This article is informative and does not substitute the consultation of a specialist.