Does milk thistle help with depression? What the research does and doesn't show

No published human trial has tested milk thistle, silymarin or silibinin for depression. A 2023 systematic review of 17 studies found only animal and mechanism-level research on how these compounds affect depression-related brain chemistry, and its authors said clinical studies in people are still needed before drawing conclusions.

What the evidence doesn't support

It doesn't support milk thistle, silymarin or silibinin as a treatment for depression, major depressive disorder, or any other diagnosed mood condition, and it isn't a substitute for prescribed antidepressant treatment. No trial has given milk thistle to a person with depression and measured the outcome — the mechanism findings below all come from animal models. None of it describes a specific product's dose, and nothing here is a claim about any product.

What the trials found

A 2023 systematic review in Central Nervous System Agents in Medicinal Chemistry pooled 17 studies on silymarin and silibinin's effects in the central nervous system, specifically looking at depression and anxiety. Every included study was conducted in animals or isolated tissue, not people: in rodent models, silymarin and silibinin raised brain-derived neurotrophic factor and increased neural stem cell activity in the hippocampus, changed serotonin, dopamine and norepinephrine levels, and lowered inflammatory cytokines (IL-6, IL-1β, TNF-α) associated with stress-induced depressive behavior in those animals. The review's authors describe these as candidate mechanisms worth pursuing in people and explicitly state that more clinical studies are needed — which means the field currently has a rationale for a human trial, not a human trial. We found no separate published clinical trial measuring depressive symptoms or a diagnosed depressive disorder in people given milk thistle, silymarin or silibinin.

Separately, a 2019 human safety review of silymarin at doses up to 2,100 mg/day for 24 weeks reported gastrointestinal upset, headache and skin reactions as the main effects in trial participants, with no mention of mood changes in either direction. Those trials weren't designed to measure mood, so this is an absence in the reported record rather than a direct test.

Questions people ask

Can milk thistle help with depression?

Not according to any published human trial, because none exists yet. The only research is in animals, and it looked at brain chemistry changes rather than depressive symptoms in a person. The review's own authors call for human trials before any conclusion is drawn.

Is there any human data on milk thistle and mood?

Not for depression specifically. The human trials that exist for milk thistle focus on liver, kidney and metabolic markers (see milk thistle benefits: what the research does and doesn't show) and weren't designed to measure mood.

When to talk to a doctor

Anyone experiencing symptoms of depression, or already diagnosed with a depressive disorder, should talk to a doctor; milk thistle is not a treatment for depression, and nothing in the research above tested it as one. If you take a prescription antidepressant or any other medication, ask a doctor before adding milk thistle — see milk thistle and medications: what to check.

Related reading: milk thistle and anxiety, milk thistle: what the research does and doesn't show, and what is milk thistle.