Valerian Root

Supplements · Sleep & Calming Herbs · Supplement, Typed Supps

Mixed evidence, and gentler than its reputation.

Stage by stage

Intake (Capsule, extract, or tea): Active compounds are absorbed in the small intestine.
Small intestine (Absorbed): Active compounds are absorbed in the small intestine.
Bloodstream (Crosses into the brain): Reaches the brain after absorption.
Brain (Interacts with GABA system): Thought to mildly interact with the brain’s calming GABA system.

What the evidence supports

Improving sleep quality — limited evidence. Pooled analyses are inconsistent — some show subjective improvement with no objective change, others show nothing. Preparations vary enormously, which makes trials hard to compare.
Reducing anxiety — limited evidence. Small trials with mixed results and considerable heterogeneity.

Typical dose

400–900 mg of extract at bedtime; trials that specified timing gave it 30 to 60 minutes before sleep

Upper limit: No formal UL. Trials have been short — many run a fortnight or less, and the longest around six to eight weeks — so long-term safety data do not exist

Timing

30–60 minutes before bed.

Time to effect

Same night: For some people.
2+ wks: More reliable effects with consistent nightly use.

Medication interactions

Sedatives, benzodiazepines, and alcohol: Additive drowsiness. (moderate)
Anaesthesia: Stop it well before surgery — it may potentiate anaesthetic agents. (high)

Common myth

“Valerian knocks you out immediately.” In reality: Evidence for its sleep benefit is mixed and generally modest.