Milk Thistle
Milk thistle is the most-studied herb for liver health. Its active compound, silymarin, protects liver cells from damage and supports their regeneration.
Milk thistle's active compound, silymarin (a group of flavonolignans, primarily silybin), protects liver cells from toxins, reduces oxidative stress, and supports liver regeneration. It's one of the few natural compounds with genuine hepatoprotective evidence.
Good for you if: You drink alcohol regularly, take medications that stress the liver, have elevated liver enzymes, or want general liver protection.
Dive deeper into the researchCommon side effects
- Mild GI upset (bloating, diarrhoea) in some people
- Headache (uncommon)
- Allergic reactions in people allergic to ragweed or daisies
What does milk thistle do?
Your liver processes every toxin, medication, and metabolic waste product in your body. Silymarin — the active compound in milk thistle — does three things for your liver: it protects liver cells from damage by acting as an antioxidant, it blocks toxins from entering liver cells by altering cell membrane structure, and it stimulates regeneration by promoting protein synthesis in damaged liver cells.
What can you expect?
- Lower liver enzymes — ALT and AST often normalise within 4–8 weeks
- Better toxin processing — liver handles alcohol and medications more efficiently
- Antioxidant protection — reduces oxidative damage in liver tissue
- Support during medication use — protects against drug-induced liver stress
How to take it
200 mg silymarin (80% standardised extract) twice daily with meals. Look for phospholipid-complexed forms (Siliphos/silybin-phytosome) for better absorption — standard silymarin has poor bioavailability.
For active liver support (elevated enzymes or heavy alcohol use), 400–600 mg/day of silymarin is used in clinical trials.
Watch your liver enzymes improve
eterni tracks ALT, AST, GGT, and other liver markers over time — so you can see if milk thistle is doing its job.
Get early accessFrequently Asked Questions
Does milk thistle actually help the liver?
Yes. Silymarin has genuine hepatoprotective properties backed by decades of research. It consistently lowers elevated liver enzymes (ALT, AST), protects against drug-induced liver injury in animal studies, and is used clinically in Europe for liver support. It won't cure serious liver disease on its own, but it provides meaningful protection and support.
Can I take milk thistle if I drink alcohol?
Yes, and it's one of the most evidence-based reasons to take it. Silymarin protects liver cells from alcohol-induced oxidative damage and supports regeneration. That said, it's not a licence to drink more — reducing alcohol intake is always the most effective liver protection strategy.
Which form is best absorbed?
Standard milk thistle extract (80% silymarin) has poor oral bioavailability — only about 20–50% is absorbed. Phospholipid-complexed forms (like Siliphos or silybin-phytosome) improve absorption by 4–10 fold. If your budget allows, choose the phytosome form. If not, standard extracts still work — you just need higher doses.
Does milk thistle interact with medications?
Silymarin can inhibit certain CYP450 enzymes (CYP2C9, CYP3A4) and drug transporters, potentially altering levels of some medications. Significant clinical interactions are uncommon at standard doses, but if you're on medications with narrow therapeutic windows (warfarin, certain HIV drugs, immunosuppressants), check with your doctor or pharmacist.
How milk thistle works
Silymarin is a complex of at least seven flavonolignans, with silybin (silibinin) being the most active. Silybin stabilises hepatocyte cell membranes by altering their lipid composition, preventing toxin entry. It scavenges free radicals and inhibits lipid peroxidation in liver tissue. It stimulates ribosomal RNA polymerase I, promoting protein synthesis for liver cell regeneration. Additionally, silymarin inhibits NF-κB and reduces stellate cell activation — the process that leads to liver fibrosis.
What the studies show
- Liver enzymes: Meta-analysis — silymarin reduced ALT by 8–15 U/L and AST by 5–10 U/L in patients with liver disease
- NAFLD: Multiple RCTs show silymarin improves liver enzymes, insulin resistance, and ultrasound findings in non-alcoholic fatty liver disease
- Amanita poisoning: IV silibinin is an approved treatment for death cap mushroom poisoning — demonstrating its potent liver-protective effects
- Drug-induced liver injury: Animal studies consistently show protection against paracetamol, methotrexate, and other hepatotoxic drugs
Side effects & safety
- GI upset — Mild bloating, loose stools, or nausea. Usually resolves within a few days. Take with food.
- Headache — Uncommon, usually in the first week.
- Allergic reactions — If you're allergic to plants in the Asteraceae family (ragweed, daisies, marigolds), you may react to milk thistle.
- Estrogenic effect — Silymarin has weak estrogenic activity in cell studies. Clinically insignificant at standard doses, but relevant for hormone-sensitive cancers.
Which labs to check
- ALT, AST, GGT — the primary liver enzymes; check at baseline and 8–12 weeks
- ALP & bilirubin — additional liver function markers
- Albumin — reflects synthetic liver function
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eterni connects your lab results, supplements, and retests — so you can see the trajectory, not just a snapshot.
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