Full profile

Also known asValeriana officinalis, Valerian root
Best forTraditional evening sleep-onset support (efficacy unproven) · A calm-slot option for people who tolerate it
Evidence gradeGrade C — Limited — early or small human trials
Studied dose range225–1215 mg/day of extract; most commonly 300–600 mg taken 30–120 minutes before bed.
Time to effectInconsistent; where any benefit appears it tends to require repeated nightly dosing over ~2–4 weeks rather than a single dose.
Best formAqueous or hydroethanolic root/rhizome extract; standardization (valerenic acid) is inconsistent across products, which is a core reason the evidence is muddy. Odor and palatability are poor.

Evidence, honestly graded

Limited and genuinely borderline — graded C only because there is no safety or legal veto to justify Graded Out, not because the evidence is convincing. The strongest systematic reviews conclude the evidence is inconclusive (Stevinson 2000) and that the only positive result is a dichotomous self-reported "slept better" that disappears on objective measures, with documented publication bias (Bent 2006). A more favorable 2020 review (Shinjyo 2020) reports benefit but pools 60 heterogeneous studies and blames inconsistent results on variable extract quality. Under a replication-over-recency standard, the honest read is "traditional use, efficacy unproven" — we would not headline an efficacy claim on valerian.

See the full grading rubric — study type, replication, population match, and dose adequacy — in The Evidence Standard.

Side effects

  • Headache, dizziness, GI upset, morning grogginess
  • Occasional paradoxical stimulation
  • Rare hepatotoxicity case reports (largely combination products or confounded)

Who should avoid it or check first

  • Pregnancy or breastfeeding (insufficient data)
  • Before driving or operating machinery
  • Pre-existing liver concerns
  • Within 1–2 weeks of surgery (anesthesia potentiation)

Interactions

  • Adds to the effect of CNS depressants — benzodiazepines, barbiturates, alcohol, opioids, sedating antihistamines — and to anesthesia

Stacks well with

  • Lemon Balm (traditional pairing)

Use caution stacking with

  • Other sedatives or sleep agents without clinician guidance

What to look for on a label

  • Do not headline an efficacy claim — the objective evidence does not support one. Traditional-use wording only.
  • Health Canada's labelling standard permits a "sleeping aid / sedative" claim on a traditional-use-and-safety basis, which is not a finding that clinical efficacy is proven — keep the two separate.

References

Grades and studied doses are our conservative reading of the human research, shown for education. They are not product claims, and a studied dose is not a recommended dose.

See how Valerian compares on grade, dose, and goal in the Evidence Explorer.