10 Facts About Garlic Dosage For UTI

Using garlic to treat UTI is not a novel idea, but what is the right garlic dosage for UTI? In this post we will investigate why garlic (Allium sativum) could be useful in UTI treatment, what do we know about why garlic works, how much garlic you should take to supplement your UTI treatment, and what else you need to know if taking garlic for UTI.

#1 Garlic Is An Ancient Remedy

Garlic has been known for its antibacterial properties for ages.

For example, garlic was one of the plants recommended for its antimicrobial properties in Meddygion Myddvai, a 14th-century Welsh manuscript.

You might have heard that we live in “post-antibiotic era”, which means known antimicrobials are becoming less effective due to the pathogenic bacteria becoming resistant. That’s why researchers are turning to plants to find ideas, inspiration, and new cure for infections like UTI.

In an attempt to validate long known remedies and to understand their mechanism of action, hundreds of in-vitro (in a lab) studies have been performed with garlic extracts. Garlic extracts were also used in many animal models to verify it’s effectiveness against various bacteria.

There are also plenty of studies that cover effects of garlic on cholesterol, blood pressure, red blood cells, cancer, and weight loss in human clinical studies. However, I was not able to come across a clinical, human in-vivo study related to UTI (besides a two-case UTI prevention report that I’ll mention later).

This does not mean that garlic is useless against UTI, but it definitely means that there is no recommended, clinical evidence-based garlic dosage for UTI.

#2 Calculating Garlic Dosage For UTI

In studies, time and time again, garlic demonstrates strong antibacterial properties. If you just glance through the results, it easy to feel convinced that garlic could cure a UTI and all other diseases in the world along with it.

However, most of the studies are performed in a lab (in vitro) or on animals, and animal models are different than human experiments.

In one such study (Evaluation of Phenolic Compounds and Antioxidant and Antimicrobial Activities of Some Common Herbs), “the antimicrobial activities of medicinal plants extracts were determined using disc diffusion method. 100 μL of suspension, having 104 CFU/mL of fungal spores and 108 CFU/mL of bacterial strains, was dispensed on potato dextrose agar and nutrient agar medium, respectively.”

This basically means that the lab placed bacterial strains on a round plate. Then, a drop of garlic extract was added precisely in the middle. After some time, researchers measured so-called “inhibition zones diameter “. Basically, they look at how far from the center the bacteria were killed by the extract that was placed in the middle. These measurements compared to the effect of known antibiotics (in this example, Rifampicin).

As a conclusion, the study announced that garlic demonstrates antimicrobial activities (by the way, garlic was still twice less effective than Rifampicin) since it killed bacteria in approximately 5 mm radius.

It is, of course, wonderful news: another study confirms that garlic has antibacterial properties. But do you see any problems with that? Can you, from this study, figure out how much garlic you’d need to combat a UTI?

Let me give you another example, in a similar study (an Antimicrobial activity of fresh garlic juice: An in vitro study), that used fresh garlic juice (FGJ) instead.

The study established that the higher concentration of garlic juice, the better it’s antimicrobial activity (duh!): “Ten percentage of FGJ showed ≥10 mm zone of inhibition in E. coli and S. aureus, while 25% concentration of garlic juice showed >15 mm of the zone of inhibition in S. aureusP. mirabalis and E. coli.”

What does it tell you? Will you be able to figure out garlic dosage for UTI based on this results? A simple answer is no. Even though we know the exact concentration of garlic extract needed to demonstrate antibacterial properties, we do not pump garlic juice directly into our bladders.

Perhaps, home remedy enthusiasts might suggest we simply need to calculate how much garlic juice we need in order to reach the same level of garlic juice concentration in our own bladders, a then we could identify the garlic dosage for UTI. However, your body metabolic processes have to be considered.

Unfortunately, by the time garlic juice is fully metabolized and the leftovers reach your bladder, the chemical composition of this “juice” is totally different.

#3 Garlic Is Antibacterial

When you drink garlic juice or eat raw garlic, the beneficial substances undergo major transformations leading to compounds that were not present in the original product (raw garlic or garlic supplements). These compounds are still not well researched.

For example, you might know that Allicin (diallyl thiosulfinate), derived from garlic, is a highly potent natural antimicrobial substance. It inhibits the growth of a variety of microorganisms, among them antibiotic-resistant strains.

But Allicin is not even present in the intact garlic clove, it is only released if you cut or crush garlic (it is generated by the enzyme alliinase in the course of cell disruption).

Furthermore,  Allicin’s life is rather short: Allicin is never detected in urine regardless of whether you take raw garlic or garlic pills, which leads us to conclude that Allicin is processed in the body into new compounds.

We know that these compounds include disulfides, trisulfides, dithiins, and ajoenes. Since this is what is detectable in urine after garlic consumption. All we know for now, that these compounds constitute the typical aroma of garlic but may also contribute to its beneficial health effects.

#4 Garlic Is Safe For Good Bacteria And Kidneys

Since I’m always concerned about the wellbeing of my microbiota, I want to know how antibacterial remedies that I take affect it.

Good news, per another study results, water-based garlic extract significantly “enhanced the growth of one strain of probiotic bacteria (L. reuteri) whilst inhibiting both pathogenic strains of E. coli at a 1:50 dilution.” Obviously, there are thousands of other probiotic strains that we should worry about, but at least we have one data point confirming that garlic based remedy won’t hurt your own good bacteria.

Read more about why beneficial bacteria are critical in your fight against recurrent UTI.

Some doctors were concerned if consuming garlic might have a detrimental effect on kidney health. In contrary, a study named The Beneficial Effects of Allicin in Chronic Kidney Disease Are Comparable to Losartan established that Allicin showed “antihypertensive, antioxidant, and nephroprotective effects”. Basically, garlic lowers blood pressure and keep your kidneys healthy.

When comparing the beneficial effects of Allicin to those of losartan: “In fact, the effect of allicin on blood pressure and renal function is comparable to reductions seen with losartan, a prescription drug commonly used as a first-line therapy”, concludes the author. So if you have high blood pressure (perhaps, because of all the UTI nerves), garlic will help to kill two birds with one stone.

Other beneficial effects of garlic mentioned in research papers:

  •  Reduces total cholesterol and Low-density Lipoprotein (LDL-C),
  •  Increasing High-density Lipoprotein (HDL-C).
  •  Provides a variety of anti-cancer properties.

#5 Could Garlic Destroy Bacterial Biofilms?

Probably one of the most important discoveries for chronic UTI sufferers is that garlic can affect bacterial biofilms.

E.coli that causes UTIs is known to form biofilms that enable bacteria to avoid attacks from our own immune systems, resist antibiotics and therefore becoming the source of persistent chronic infections. Fighting a chronic infection without destroying the biofilms is impossible.

Subinhibitory Concentrations of Allicin Decrease Uropathogenic Escherichia coli (UPEC) Biofilm Formation, Adhesion Ability, and Swimming Motility study investigated the effect of Allicin, isolated from garlic essential oil, on pathogenic E.coli, biofilm formation and growth, along with its effect on ability of E.coli to adhere to bladder walls and move around (“motility”).

As the result, it was established that Allicin decreased pathogenic biofilm formation and affected its architecture. Allicin was also capable of dispersing biofilm. Furthermore, allicin decreased the bacterial adhesion ability and swimming motility, which are important for biofilm formation”. Basically, incapacitating E. coli bacteria and partially disabling it.

The study also revealed that the presence of 50 µg/mL allicin decreased the expression of UPEC type 1 fimbriae adhesin gene fimH. This means that E. coli can’t grow their little nasty hands that they use to grab on to your bladder walls and this, in return, allows you to flush the bacteria out.

The major problem though: Allicin as I mentioned above, is not even detectable in urine (regardless of how much garlic you ate). However, let’s hope that after Allicin is metabolized by our body, the resulting components still carry on similar qualities as their parental compound.

#6 What Is Garlic Dose For UTI?

As I mentioned earlier, it is hard to know till we actually study garlic dosage for UTI in a human clinical research.

However, you are already eating garlic, I assume. Therefore, you might as well try to see if it could help you to supplement your preventive or treatment plan. Obviously, if you have been experiencing your symptoms for more than a day and you keep feeling worse, do not experiment with any supplements and seek medical help.

If you are already taking antibiotics, most likely it is OK to supplement with garlic as a way to give your therapy a boost, but make sure to consult with your physician first.

And now, let’s look at what dosages seem to work in other studies and didn’t cause side-effects.

Maintenance garlic dose

  • Most human studies with garlic averaged a dose in a range of 600-1,200 mg garlic extract, usually divided into multiple doses and taken with or after food.  This seems to be a very safe dose, and on average comes close to an intake of one supermarket clove (weighs about 4-7 grams). 
  • Only one UTI related human study that references garlic supplementation, mentions that women took 2-6 garlic oil softgels per day along with other supplements to prevent UTI.

Treatment garlic dose supplementation

  • The garlic dosage for UTI that worked for some seems to be up to 9 garlic cloves a day, split into three equal doses.
  • You can cut garlic into pill size pieces, but I would recommend crushing it as much as possible before swallowing to release potent Allicin. The problem with this dosage is, obviously, that cloves are not a unit of weight.
  • One garlic clove weights anywhere from 4-30 grams. So make sure to use a digital scale to stay under the toxic limits (see below).

#7 What Garlic Dose For UTI Is Too Much?

Garlic can be toxic if consumed in very high doses, so supplementation should never go beyond 5% of the diet (total weight of all food you eat). Basically, if you ate 5 grams of garlic, make sure you also ate 95 grams of some regular food.

Do not take large doses of garlic when hungry, it could become more toxic.

This results in the following maximum dosages:

  • 17 grams for a 150 lb person (Approximately 5-7 garlic cloves per dose, if taken with 300-340 grams of food)
  • 22.7 grams for a 200 lb person (Approx. 7-9 garlic cloves)
  • 28.4 grams for a 250 lb person (Approx. 9-11 garlic cloves)

The lowest dose associated with raw garlic toxicity was about of 400mg/kg and resulted in testicular toxicity.

Individual susceptivity to garlic toxins could vary, so don’t go crazy.

#8 How Soon Garlic Should Work?

A research paper named Detection of Volatile Metabolites Derived from Garlic (Allium sativum) in Human Urine highlights, or example three garlic-derived metabolites, AMS, AMSO, and AMSO2, that reach it’s maximum concentration in urine at about 1 h after garlic consumption.

#9 Other Precautions And Drug Interactions

Garlic interacts with Saquinavir (even in small doses), and with Warfarin (in larger doses). As with any home remedy treatment, consult your physician for any other contradictions.

It is possible to be allergic to garlic supplements if you are allergic to garlic itself.

#10 How To Consume Garlic?


Microwaving garlic will partially destroy the beneficial components of the vegetable, but grilling and roasting will not damage the bioactives, provided the garlic is sliced or crushed beforehand to release Allicin.

Some also make garlic tea. I personally find even idea of garlic tea disgusting. I’d rather eat it crushed with bread, sour cream and salt. Or just swallow crushed garlic fast and eat some bread afterward.


When choosing raw garlic, go for purple colored bulbs (versus white). Purple ones have a higher content of beneficial flavonoids.

Make sure to weight your garlic cloves and don’t just eye the amount of garlic when trying to estimate garlic dosage.

An average garlic clove yields 9 milligrams to 15 milligrams of Allicin when crushed. Most garlic supplements express an amount of Allicin in mcg. Divide by 100 to get milligrams. Divide by 1000 to get grams.


Most garlic supplements are standardized on allicin potential and are enteric-coated to prevent gastric acid inactivation of the allicin-producing enzyme, alliinase.

A study called Low allicin release from garlic supplements: a major problem due to the sensitivities of alliinase activity found out that 83% of 24 known brands of enteric-coated tablets are releasing less than 15% of their potential. “Only when tablets had high alliinase activity and disintegrated rapidly did they show high allicin release.”

Therefore, go with capsules instead.

Have you tried garlic for UTI treatment or prevention supplementation? Please share your experience in comments below.

To summarize:

  • Raw garlic should not exceed more than 5% of your total food consumption
  • Make sure to use a digital scale to avoid taking too much garlic
  • For supplementation, choose purple garlic over white garlic
  • Garlic has known interactions with certain prescription medications
  •  2-6 garlic oil softgels per day could be taken to supplement your UTI prevention plan
  • The garlic dosage for UTI that worked for some seems to be up to 9 garlic cloves a day, split into three equal doses.

22 thoughts on “10 Facts About Garlic Dosage For UTI”

  1. Hi, thank you for sharing this – it’s nice to see some validation.
    Garlic has worked for me twice with UTIs so I don’t think it was a fluke. The first time I was without health insurance so I made an appointment at a local clinic and they could not see me for a week. I researched on line for home remedies and learned about raw garlic ( I cut it into small, easy to swallow pieces). Within 24 hours my symptoms had lessened and within 3 days it was completely gone. I cancelled the appointment. I averaged 3 – 4 cloves of garlic 3 times a day. The second time I felt the beginnings of a UTI and just started the same raw garlic regimine. 2 Days later it was gone.

    1. Anastasia Visotsky

      Sarah, thanks so much for sharing! It’s great that this approach is working for you. Cutting it up in as small pieces as possible will help to release allicin, so good job!

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