Digestion/Hormonal/Inflammation

Milk Thistle

Herbal seed extract that may modestly improve liver enzymes and some metabolic markers in adults with liver stress.

score

evidence

Caution

risk

Our methodology: How we evaluate supplements and turn the underlying research into a single rating.

Read full methodology

Use with caution

This supplement may interact with medications, medical conditions or sensitive populations. Review safety before use.

Overview

Forms

Safety

Stack

Quick Take

Reasonable if you want liver-focused support, but evidence is mixed and benefits are usually modest.

Milk thistle is an extract from the seeds of Silybum marianum, a Mediterranean plant; supplements usually concentrate the flavonolignan complex called silymarin, especially silybin. It works mainly through antioxidant and anti-inflammatory actions that help protect liver cells and support glutathione recycling. Human studies suggest modest improvements in liver enzymes, with weaker evidence for glucose control and inflammatory markers. It is most relevant for adults with fatty-liver risk factors or mild liver lab abnormalities.

Potential benefits

Improves ALT/AST in fatty liver

May lower fasting glucose/HbA1c

May lower CRP/TNF-α

May lower ALT/AST on meds

May improve fibrosis markers

Protocol

Amount

200-420 mg silymarin equivalent

Frequency

Once to three times daily with meals, depending on form

When

With meals to improve tolerability; phytosome forms may allow lower doses than standard extracts.

Onset Time

4-8 weeks for lab changes; longer for imaging or fibrosis measures.

Who Should Consider

Adults with fatty-liver risk factors

People with mildly elevated ALT/AST

Adults with metabolic syndrome or high fasting glucose

People on medications with liver monitoring

How It Works

Silymarin, especially silybin, helps limit oxidative stress in liver tissue, supports glutathione-dependent defenses, and dampens inflammatory signaling such as NF-κB. It may also help stabilize hepatocyte membranes and modestly improve insulin signaling in metabolically stressed adults.

Updated 5/19/2026