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Limited evidenceSleep & relaxation

Valerian Root

Valerian is the most-studied herbal sleep aid and still has not clearly beaten placebo on objective sleep measures. Trials are small, old, methodologically weak and use wildly different extracts, so any real effect is probably small.

What the science says

  • Improves subjective sleep quality (weakly) Limited evidence

    A meta-analysis of 18 placebo-controlled trials found that when sleep quality was scored as a yes/no "improved" outcome, valerian users were about 1.8 times more likely to report improvement (RR 1.8, 95% CI 1.2-2.9). But when the same trials were analysed with continuous measures such as sleep latency, no significant benefit remained, heterogeneity was high and study quality was poor.

  • Improves objective sleep (polysomnography, actigraphy) Limited evidence

    A 2024 umbrella review of the valerian literature concluded the evidence base is low-quality and inconsistent, with no reliable effect on sleep-onset latency, total sleep time or sleep efficiency. Positive findings cluster in small, short, industry-linked trials.

  • Reduces anxiety Limited evidence

    Anxiolytic trials are few, small and mostly use combination products with hops or lemon balm, making valerian's own contribution impossible to isolate. There is no adequately powered RCT of valerian monotherapy for a diagnosed anxiety disorder.

Dosage & safety

Studied doseTrials typically used 300-600 mg of a dried root extract (some up to 900 mg) taken 30-120 minutes before bed, for 2-4 weeks. Aqueous, ethanolic and standardised valerenic-acid extracts are not interchangeable, and product labelling is often unreliable. Effects, if any, are reported to build over 1-2 weeks rather than acting like a hypnotic on night one.
SafetyGenerally well tolerated; the most common complaints are morning grogginess, headache, vivid dreams and GI upset. Rare cases of hepatotoxicity have been reported, almost always with multi-herb products, so the causal role of valerian itself is unclear. Effects are additive with alcohol, benzodiazepines, Z-drugs and other sedatives; avoid before driving. Not recommended in pregnancy, breastfeeding or in children due to absent safety data, and stopping abruptly after long-term high-dose use has anecdotally been linked to withdrawal-like symptoms.

Scientific references

Where to buy

NOW Foods, Valerian Root Extract, 2 fl oz (59 ml)

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