Dandelion Root Extract: 0.5 g to 40 g of Root a Day, by Label

Search for dandelion root extract and the results agree with each other: it supports the liver, it helps you shed water, it may lower blood sugar, and it kills cancer cells. We went to the documents underneath those claims instead. These were the European regulator’s full review of dandelion root, the NIH’s database of US supplement labels, PubMed, and the US trial registry. We checked all of it on 29 October 2026.

Three things came out that the usual pages leave out. The European review found no clinical studies of dandelion root at all. Its rules advise against the root in exactly the condition most US labels promote it for. And what counts as a day’s dose of “dandelion root” varies about eighty-fold from one bottle to the next.

The EU looked for clinical studies and found none

The European Medicines Agency’s herbal committee published its assessment of dandelion root in November 2021, after reviewing the literature to 2020. Its clinical section is one line repeated: efficacy, dose-response, clinical studies, special populations, all “No data available”. Its conclusion:

The well-established use cannot be supported, because no clinical studies were found.

The committee still approved dandelion root as a traditional herbal medicine, which in EU law means a use documented in handbooks for decades rather than one shown in trials. It allowed three such uses: relief of mild digestive symptoms “such as feeling of abdominal fullness, flatulence, and slow digestion”, temporary loss of appetite, and increasing urine flow “as an adjuvant in minor urinary complaints”. Liver support, blood sugar, weight and cancer are not on the list.

The vote was 25 of 26. Ireland’s member dissented, saying the appetite and urinary indications were “not acceptable” for a traditional herbal medicine.

NCCIH, the US government’s centre for complementary health, reaches the same place more bluntly: “There’s no compelling scientific evidence supporting the use of dandelion for any health condition.”

The liver warning US labels leave off

Here is the part of the EU monograph that matters most for the most common reason people buy this supplement:

Due to possible stimulation on bile secretion, dandelion root is not recommended in case of obstruction of the bile duct, cholangitis, liver disease, gallstones and any other biliary diseases.

We read the 82 single-ingredient dandelion root label records the NIH Dietary Supplement Label Database returned for “dandelion root”, all marked as on the market. Some are earlier versions of the same product. 28 of them use liver language: “Promotes healthy liver function”, “Supports liver & kidney health”, “Liver Support”, “Stimulates the liver”.

None of the 28 says what the EU says. Four carry a warning against use with a blocked bile duct or gallbladder inflammation. That is a narrower version of the same caution, and it is the most careful wording we found. One, NutraBio, asks people with “kidney or liver disease” to consult a practitioner. The rest promote the liver with no liver caution at all.

So the person most likely to reach for a liver-support bottle, someone who has just been told their liver numbers are off, is the person the European monograph says should not take it without medical advice.

The human trials used the leaf

Most pages cite a diuretic study as human evidence for dandelion root. It exists, but it tested the leaf. In the 2009 pilot, 17 volunteers took a fresh dandelion leaf extract three times over one day. Urination went up after the first two doses, and “the third dose failed to change any of the measured parameters”. There was no placebo group; each person was compared with their own previous two days.

The only other trial of dandelion on its own that we found in the US registry also used the leaf. NCT06625736 gave 120 women “500 mg capsules of dandelion leaf extract” three times a day for 12 weeks, against the weight-loss drug Xenical. It was completed in September 2024. No results are posted, and we found no publication in PubMed.

The newest trial to include dandelion root is a 2026 study of a liquid containing turmeric, dandelion, milk thistle and ginger in 130 healthy adults. Liver enzymes improved more than with placebo. The product maker funded it and, according to the paper’s conflict statement, had a hand in “the study design, interpretation of data, writing of the manuscript, and the decision to publish”. With four herbs in one drink, it cannot tell you anything about dandelion. Our milk thistle stacks page covers why combinations like this inherit the weakness of their parts.

What “a dose” means depends on the bottle

The EU’s traditional dose is 1 to 5 g of cut dried root boiled as a tea, two to three times a day: 2 to 15 g of root a day. Capsules and powders in the US are labelled in milligrams, and some are concentrated extracts with a ratio such as 4:1 or 20:1. A 20:1 ratio means 20 parts of raw root went into each part of extract.

Following each label’s own directions, here is what a day looks like:

Product (NIH label ID)	What the label lists	Daily amount by label directions	Root equivalent per day
NOW Dandelion Root 500 mg (314132)	500 mg root, no extract ratio	1 capsule	about 0.5 g
GNC Herbal Plus Dandelion Root 550 mg (315294)	550 mg root powder	1 capsule	about 0.55 g
Wonder Laboratories Dandelion Root 520 mg (315380)	520 mg root	1-2 capsules	up to about 1 g
Nature’s Way Dandelion Root 1,575 mg (333717)	1,575 mg root per 3 capsules	3 capsules	about 1.6 g
BulkSupplements Dandelion Root Extract (330785)	500 mg of 4:1 extract	500 mg once or twice	up to about 4 g
Nature’s Answer Dandelion Root, alcohol-free (295434)	2,000 mg dry herb equivalent per 2 ml	1-2 ml three times	up to about 6 g
Nutricost Dandelion Root 1575 mg (223501)	1,575 mg of 4:1 extract	up to 3 capsules	up to about 6.3 g
Herbadiet Dandelion Extract (244723)	500 mg of 10:1 extract	1 capsule twice	about 10 g
Micro Ingredients Dandelion Root 20:1 Extract (231533)	1 g of 20:1 extract	1 scoop twice	about 40 g
NutraBio Dandelion Root 500 mg (309356)	1.5 g water extract	3 capsules	cannot tell: no ratio given

The root-equivalent column is our arithmetic from each label’s ratio, and it is only approximate: an extract is not simply ground-up root, and different solvents pull out different compounds. The point it makes is about scale. The typical 500 mg capsule taken as directed gives less root than the bottom of the EU’s tea range. At the other end, a 20:1 powder taken as directed corresponds on paper to more than twice the top of it. Neither has been tested, and the labels do not say which kind you are holding unless you look for the ratio.

Two labels also make claims the EU did not accept. Nature’s Way calls its root capsules a “Traditional diuretic herb”, which is closer to the leaf evidence than the root’s. The Micro Ingredients 20:1 powder says it can “lower blood pressure”, a use that appears nowhere in the EU’s review.

The cancer research is in cells and mice

The cancer claims trace to a University of Windsor laboratory. In 2012 its researchers reported that an aqueous dandelion root extract killed chronic myelomonocytic leukemia cells and pancreatic cancer cells in culture while leaving normal cells alone. These were cell-line experiments. Similar studies in colon, prostate, breast and gastric cancer cells followed from other groups.

In February 2015 the university announced a trial at the Windsor Regional Cancer Centre with “room for 30 patients who have exhausted all other cancer treatments”. We searched PubMed and the US trial registry and found no published results from it. The only human report we found is a 2018 case of one 76-year-old man with chronic myelomonocytic leukemia who took papaya leaf extract and dandelion root extract together, and whose blood counts held steady. One case, with two products, cannot show what either did.

Killing cancer cells in a dish is a low bar that many plant extracts clear. Anyone with cancer who wants to try dandelion root should raise it with their oncologist, not instead of treatment.

Safety: mostly unknown, with one kidney warning

The EU monograph lists allergic reactions as the only known side effect. It rules out use in people allergic to the daisy family (Asteraceae), which includes ragweed. It does not recommend it in pregnancy or breastfeeding, for lack of data, or for children under 12. Reproductive toxicity, genotoxicity and carcinogenicity tests “have not been performed”. The EU found no reported drug interactions. NCCIH flags theoretical ones with diabetes medicines, blood thinners, antiplatelet drugs and water pills.

One case in the EU file is worth knowing about if your kidneys are not working well. A man on haemodialysis had been drinking 10 to 15 cups of dandelion tea a day for six months. He developed very high blood oxalate and gangrene in his fingertips, and tea from the same source tested high in oxalate. The plant part was not recorded. It is a single case in someone whose kidneys could not clear oxalate, and it should not worry a healthy person drinking a cup. It is a reason for anyone with kidney disease to ask before starting a daily habit.

No product box on this page

The evidence does not support buying dandelion root extract for any particular result, so there is no product link here. The one specific finding a reader can act on is a caution: if you have liver disease, gallstones or a bile duct problem, the EU’s herbal committee advises against dandelion root, whatever the bottle says.

The bottom line

Dandelion root extract is sold for the liver, water retention, blood sugar and cancer. The European regulator found no clinical studies of the root for anything, and approved it only for traditional use: mild indigestion, poor appetite and flushing the urinary tract. It also advises against the root in liver disease and gallbladder disease, a warning absent from all 28 of the US labels we read that promote it for the liver. The human trials of dandelion on its own used the leaf. The cancer work is in cells and mice. And depending on which bottle you pick up, a day’s dose ranges from about half a gram to about 40 grams of root, so if you do take it, read the extract ratio first.