Mood

St John's Wort

Herbal extract used for mild to moderate low mood, with antidepressant-like effects and unusually important drug interactions.

score

evidence

Caution

risk

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Use with caution

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

Overview

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Safety

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Quick Take

Can help mild low mood, but only if you screen carefully for drug interactions first.

St John's wort is a botanical extract from the flowering tops of Hypericum perforatum. Its active compounds, especially hyperforin and related constituents, influence serotonin, norepinephrine, dopamine, glutamate, and GABA signaling. Best evidence supports mild to moderate depressive symptoms, with weaker evidence for anxiety, sleep symptoms tied to low mood, and some female-specific mood complaints. It fits best for adults with persistent low mood who are not taking interacting medications.

Potential benefits

Reduces depressive symptoms

May reduce anxiety symptoms

May improve sleep in low mood

May improve quality of life

May ease PMS low mood

May ease menopausal low mood

Protocol

Amount

900 mg

Frequency

Split into 2-3 doses daily

When

With food to reduce GI upset; take earlier in the day if it feels activating.

Onset Time

Usually 2-4 weeks, with fuller effects by 6 weeks

Who Should Consider

Adults with mild to moderate low mood

People with low mood plus some anxiety

Adults wanting a nonprescription mood option

People taking no interacting medications

Those with recurrent seasonal low mood

How It Works

Standardized extracts appear to reduce reuptake of serotonin, norepinephrine, and dopamine, while also affecting glutamate and GABA signaling. Hyperforin also activates pregnane X receptor, which induces CYP3A4 and P-glycoprotein and explains the herb's unusually high rate of drug interactions.

Updated 5/19/2026