How much milk thistle should I take?

Trials use around 420 mg of silymarin daily, usually split into three doses. What matters is the silymarin figure rather than the milk thistle figure: 250 mg standardised to 80% gives 200 mg of silymarin, and an unstandardised 250 mg could give a fraction of that.

Does milk thistle actually repair the liver?

It does not repair anything. Trials in fatty liver disease show improvements in liver enzymes and some imaging measures, but they are small and short, and no trial has shown reversal of established damage. Intravenous silibinin is genuinely used for mushroom poisoning in hospital, which is a different thing from a daily capsule.

What does standardised to 80% silymarin mean?

It means 80% of the extract weight is the active flavonolignan complex. It is the single most useful number on a milk thistle label, and a product that does not state it is one you cannot compare to the research.

Updated August 2026Evidence-Based

Milk Thistle and Silymarin: Dose, Evidence and Limits

Also known as: Milk Thistle, Silybum marianum, Silymarin, Silybin, Silibinin, Legalon

Milk thistle is sold almost entirely as a liver supplement, and the active fraction is silymarin, a complex of flavonolignans from the seed. It is worth knowing that the evidence has not landed where the marketing sits: the better-quality results are in metabolic markers, while the liver claims the category is built on rest on trials that are smaller and less consistent than the shelf presence suggests.

Milk Thistle (Silymarin): products that state their dose

Research on milk thistle (silymarin) generally uses 420 mg/day of silymarin, in divided doses. These are the products we found that put an amount on the label, so you can check them against it. Sorted by whether they reach that figure, then by how many people have rated them.

✓
Silymarin Milk Thistle Extract 300 mg with Artichoke and Dandelion
300 mg silymarin per capsule4.7★ (6,651)$25.04
States silymarin rather than seed weight, which is the number the research is about.
View on Amazon
–
Milk Thistle Silymarin 4:1 Extract 250 mg
250 mg extract, 4:1 concentration4.6★ (28,160)$31.49
A 4:1 ratio is not a silymarin percentage, so the actual silymarin content is not stated.
View on Amazon
–
Milk Thistle 150 mg, 30:1 standardised silymarin extract
150 mg extract, 80% silymarin4.6★ (10,361)$26.94
120 mg of silymarin per capsule, so three or four a day to reach the trial amount.
View on Amazon
–
Advanced Milk Thistle, 120 softgels
Silybin phosphatidylcholine complex4.5★ (2,271)$34.50
A better-absorbed form, so the milligram figure is not directly comparable to a standard extract.
View on Amazon
–
Milk Thistle, 60 vegan capsules
Seed extract, silymarin not stated4.6★ (1,362)$30.59
View on Amazon

Prices and ratings were recorded when this page was last updated and change often; the figure on Amazon is the one that counts. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. Nothing on this list is paid placement: it is ordered on stated dose and rating volume, and we earn the same on all of it.

How Milk Thistle (Silymarin) Works

Silymarin is an antioxidant that stabilises hepatocyte membranes and appears to interfere with the uptake of certain toxins by liver cells, which is the basis of its established use in Amanita mushroom poisoning. It also inhibits several inflammatory and fibrotic signalling pathways in laboratory models.

Benefits

Fatty liver markers: a 2024 systematic review in Annals of Hepatology found silymarin improved liver enzymes and some imaging measures in NAFLD and NASH, though trials were mostly small and short.
Blood glucose and lipids: this is where the evidence is strongest. A meta-analysis of randomised trials found meaningful reductions in fasting glucose and HbA1c in type 2 diabetes, which is not what most buyers are taking it for.
Acute poisoning: intravenous silibinin is an established treatment for Amanita phalloides poisoning. That is a hospital use and says nothing about a daily capsule.

Research Summary

A 2024 meta-analysis in Annals of Hepatology covers NAFLD and NASH; a 2016 meta-analysis in the Journal of Diabetes Research covers glycaemic outcomes, and is the stronger body of the two.

Recommended Dosage

Min effective dose

420 mg/day of silymarin, in divided doses

Max safe dose

700 mg/day of silymarin in trials

Trials typically use 140 mg of silymarin three times daily, so around 420 mg per day, and the diabetes work often used similar amounts. Read the label carefully: a product stating 250 mg of milk thistle standardised to 80% silymarin gives 200 mg of silymarin, while one stating 250 mg with no standardisation could give far less. Silymarin is poorly absorbed on its own, which is why phospholipid complexes exist.

Side Effects

Mild and uncommon. Loose stools and nausea are the usual complaints and tend to settle. People allergic to other Asteraceae plants such as ragweed, chrysanthemum or daisy can react to it.

Interactions

Silymarin inhibits some CYP450 enzymes and UGT pathways in laboratory work, so it can in principle raise levels of drugs cleared that way. Clinically significant interactions have been hard to demonstrate, but anyone on narrow-therapeutic-index medication should check first.

Frequently Asked Questions

Medical Disclaimer

The content on this page is for informational purposes only and is not intended as medical advice, diagnosis, or treatment. Always consult your physician or qualified healthcare provider before starting any new supplement regimen. Individual results may vary.