Milk thistle with inulin: what the 100 mg mean
Futures Nutrition Editorial Team · 14 August 2026
Milk thistle with inulin: what the 100 mg mean
Next to the milk thistle extract, the tub lists a second ingredient: 100 mg of inulin from chicory root per tablet. The short answer to why it is there: inulin is a dietary fibre commonly used in tablet manufacture, and it has to be declared because it is present. What it is not, in this amount: a reason to choose the preparation. Inulin has exactly one authorised health claim in the EU, and that claim requires 12 grams a day — 120 times what sits in one tablet.
Placing that number is the whole point of this article. Anyone buying a milk thistle preparation is deciding about the silymarin; the inulin changes nothing about that, for better or worse.
What the ingredients list tells you
Under Article 18(1) of Regulation (EU) No 1169/2011, the ingredients of a food must be listed in descending order of weight. That single rule makes the ingredients list the most useful line on the whole pack: without any table, it tells you the order of magnitude in which something is present.
On our preparation it reads: bulking agent cellulose, extract from milk thistle seed (Silybum marianum) 20:1 (containing 80 % silymarin), inulin (from chicory root), maltodextrin, anti-caking agent magnesium salts of fatty acids.
| Position | Ingredient | What follows from it |
|---|---|---|
| 1 | bulking agent cellulose | the bulking agent is explicitly the cellulose — not the inulin |
| 2 | milk thistle seed extract 20:1 | roughly 125 mg, since the declared 100 mg of silymarin comes from it |
| 3 | inulin (from chicory root) | declared at 100 mg, so less than the extract |
| 4 | maltodextrin | a usual carrier for dry extracts |
| 5 | anti-caking agent magnesium salts of fatty acids | pressing aid, in the milligram range |
Two things are settled by that, without asking the manufacturer. First, inulin is not the bulking agent here — that one is named. Second, the order matches the declared amounts: extract before inulin, both well behind the cellulose. How to read "20:1" and "80 % silymarin", and why the milligram figure is the only comparable quantity, is covered in Milk thistle 20:1 or 80 %.
The amount itself has to appear where it appears: § 4(3) of the German food supplements regulation (Nahrungsergänzungsmittelverordnung) requires the amount per recommended daily portion for every substance with a nutritional or physiological effect. As a dietary fibre, inulin is such a substance — hence the 100 mg on the tub, and not because the figure were a selling point.
What inulin is
Inulin is a fructan: a chain of fructose units that human digestive enzymes cannot split. It passes the small intestine unchanged and is only fermented by bacteria in the large intestine. That makes it fit the legal definition of fibre under Annex I point 12 of Regulation (EU) No 1169/2011 — carbohydrate polymers with three or more monomeric units, neither digested nor absorbed in the small intestine. For nutrition calculations the conversion factor for fibre applies accordingly: 8 kJ/g, or 2 kcal/g (Annex XIV of the same regulation).
Food-grade inulin is almost always obtained from the root of chicory Cichorium intybus — the same species that Belgian endive and radicchio belong to. The chemistry of fructans, and the question of what chain length has to do with effect, belongs in a text of its own; here it is enough that chain length and origin appear in the ingredients list, not in the advertising line.
The one authorised claim — and its condition
In the EU, one single health claim is authorised for inulin, added to the list of Regulation (EU) No 432/2012 by Regulation (EU) 2015/2314:
Chicory inulin contributes to normal bowel function by increasing stool frequency
It may only be used by anyone delivering a daily intake of at least 12 g of native chicory inulin — defined as a non-fractionated mixture of monosaccharides (under 10 %), disaccharides, inulin-type fructans and inulin extracted from chicory, with a mean degree of polymerisation of at least 9. Consumers must also be informed that the beneficial effect is obtained with a daily intake of 12 g. The basis is the EFSA opinion of January 2015 (EFSA Journal 2015;13(1):3951).
One peculiarity belongs with it: the claim was authorised on 1 January 2016 and for five years was restricted to the applicant BENEO-Orafti S.A., because proprietary data tipped the scales. Since that period expired, any food business operator may carry it — under the same conditions. It is the condition our preparation fails, not the data protection: 100 mg is one hundred and twentieth of 12 g. That is why the claim is not on the tub, and why it would not be allowed there either.
The order of magnitude
More helpful than any percentage is the comparison with the amounts at which anything is measured or claimed for fibre at all:
| Reference point | Amount | Ratio to the tablet |
|---|---|---|
| one milk thistle + inulin tablet | 0.1 g | — |
| fructans from ordinary everyday food (van Loo et al. 1995) | 1–10 g/day | 10- to 100-fold |
| well tolerated daily amount of native inulin (Bonnema et al. 2010) | up to 10 g | 100-fold |
| condition of the authorised claim (Regulation (EU) 2015/2314) | 12 g/day | 120-fold |
| German Nutrition Society guiding value for total fibre (adults) | ≥ 30 g/day | 300-fold |
The second row is the one worth remembering. A review in Critical Reviews in Food Science and Nutrition systematically measured the inulin and oligofructose content of common foods and estimated daily intake in the Western diet at 1 to 10 grams per head (van Loo et al. 1995, vol. 35, pp. 525–552, PubMed 8777017). Anyone eating wheat bread, onions, leek, garlic, asparagus or Jerusalem artichoke therefore already takes in a multiple of what the tablet contributes.
A word of caution on percentages: the labelling thresholds for "source of fibre" (at least 3 g per 100 g) and "high fibre" (at least 6 g per 100 g) from the Annex to Regulation (EC) No 1924/2006 refer to 100 grams of food. For a tablet of a few hundred milligrams, such a reference quantity says nothing about how much you actually take in. The figure that counts is the one per daily portion — here 0.1 g.
What the inulin does for the silymarin
The obvious guess: the fibre is meant to improve absorption of the silymarin. There is no study on that. Silymarin is a mixture of more than twenty flavonolignans that is poorly soluble in water; the approaches actually being worked on for absorption are complexes with phospholipids and the formulation of the extract itself — not the addition of a fructan. What is documented about timing and the role of fat, and what is not, is in Taking milk thistle.
For the detour via the gut, the same holds as with iron: the prebiotic effect of inulin is measurable in the gram range, but does not automatically carry over to the absorption of other substances — and certainly not at one hundred and twentieth of the amount studied. What has been studied is mostly minerals; the orders of magnitude there are the same, and they too come from studies with amounts a food supplement does not reach.
What may not go on the pack
For inulin, several formulations are expressly not authorised in the EU register of nutrition and health claims — and the familiar ones are precisely among them:
| Formulation | Status |
|---|---|
| "is a prebiotic" / "is bifidogenic" | not authorised (entry 767) |
| "promotes a healthy gut flora" | not authorised (entry 766) |
| "improves bowel or digestive function" | not authorised |
| "Chicory inulin contributes to normal bowel function by increasing stool frequency" | authorised, from 12 g/day |
The reason for the rejections in every case: the substance was not sufficiently characterised for a scientific assessment of the claimed effect (EFSA Journal 2011;9(6):2244). It is exactly that shortcoming the later, narrowly defined version "native chicory inulin" fixes with its degree of polymerisation — which is why a claim became possible there and not in general.
For milk thistle itself there is no authorised health claim at all; applications on botanicals have been on hold for years. A preparation made of both ingredients therefore describes what is in it. Food supplements are not a substitute for a balanced and varied diet and a healthy lifestyle.
Tolerance
Fructans are among the carbohydrates that can cause bloating in a sensitive gut. A controlled cross-over trial in 26 healthy adults tested 5 and 10 g of inulin or oligofructose with breakfast: up to 10 g of native inulin a day was well tolerated, while 10 g of oligofructose clearly increased complaints; the most frequently reported was bloating, followed by a feeling of fullness (Bonnema et al., Journal of the American Dietetic Association 2010, vol. 110, pp. 865–868, PubMed 20497775).
100 mg is a factor of 100 below that, and therefore below what a slice of wheat bread brings along. Anyone strictly avoiding fructans should still know about the ingredient — which is what it is declared on the tub for.
What is in the preparation
Milk thistle (silymarin) + inulin delivers 100 mg of silymarin per tablet from a milk thistle seed extract 20:1 with 80 % silymarin, plus 100 mg of inulin from chicory root; the recommendation is one tablet a day after a meal. The reason to choose this preparation is the silymarin and its amount — the inulin is a declared ingredient, not an argument. What else there is on the shelf on the topic is shown by the liver category; a second preparation with the same ingredient, there at 30 mg, is iron + inulin.
What remains to be noted is what the EU monograph of the European Medicines Agency records for preparations from milk thistle fruit (EMA/HMPC/294187/2013): hypersensitivity to Asteraceae is a contraindication; for children and adolescents under 18, and for pregnancy and breastfeeding, there is insufficient data.
Frequently asked questions
Is the inulin a bulking agent? Not according to the label. Cellulose is given as the bulking agent, and it stands first in the ingredients list. What technological role 100 mg of inulin plays alongside it in a tablet, the pack does not say; the plain reading is that it is a declared ingredient which has nothing to do with the silymarin.
Do I get an appreciable amount of fibre from the preparation? No. 0.1 g a day stands against a guiding value from the German Nutrition Society of at least 30 g of fibre a day for adults (derivation as of 2021). The contribution is one three-hundredth — a portion of wholegrain bread or pulses does more on this question than any tablet.
Should I buy inulin separately? That is a decision of its own, not a question about the milk thistle preparation. Anyone wanting to use the authorised claim on stool frequency needs 12 g of chicory inulin a day; there are dedicated powder products for that. Tolerance is worth considering: in the trial cited, native inulin was well tolerated up to 10 g a day, above which it became unpleasant for some of the participants.
Why is the amount on the tub at all, if it is so small? Because § 4(3) of the German food supplements regulation requires it: for substances with a nutritional or physiological effect, the amount per recommended daily portion must be stated. The rule does not ask whether the amount is relevant — it only asks whether the substance is present. For the reader that is an advantage: you can do the arithmetic instead of having to guess.
Sources: Regulation (EU) 2015/2314 (authorised claim on native chicory inulin, conditions and data protection period) · Regulation (EU) No 432/2012 in its consolidated version · Regulation (EU) No 1169/2011, Article 18(1), Annex I point 12 and Annex XIV · Regulation (EC) No 1924/2006, Annex (source of fibre) · EU register of nutrition and health claims, entries 766 and 767 on inulin (EFSA Journal 2011;9(6):2244) · EFSA Journal 2015;13(1):3951 · § 4 Nahrungsergänzungsmittelverordnung · German Nutrition Society, reference values for fibre · van Loo et al., Crit Rev Food Sci Nutr 1995;35(6):525–552 · Bonnema et al., J Am Diet Assoc 2010;110(6):865–868 · European Medicines Agency, EMA/HMPC/294187/2013.
