How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Valerian
The best-selling plant against mild insomnia. It is also one of the most studied — and its largest syntheses do not agree with each other.
Benefits
- A meta-analysis of 60 studies and nearly 7000 participants (7 to 80 years old) shows that valerian improves subjective sleep quality and reduces anxiety, with no serious adverse effects
- A meta-analysis of 18 randomized trials finds a relative risk of 1.37 in favor of better perceived sleep quality
- In 128 people, 400 mg of aqueous extract reduces perceived sleep onset latency and improves subjective sleep quality, especially in poor sleepers and smokers
- In 16 patients suffering from chronic insomnia, 14 days of supplementation improve objective deep sleep parameters measured by polysomnography — an effect that only appears after repeated intake, not after a single dose
- In 12 healthy volunteers, 28 days of intake did not disrupt liver enzymes that metabolize numerous drugs, unlike other herbs tested in the same study (kava, goldenseal)
Precautions
Very well tolerated: in one trial, it even caused fewer side effects than the placebo (3 cases against 18). Above all: major systematic reviews do not agree. The 2007 review, covering 36 trials, concludes that the most recent and best-designed studies find no significant effect compared to placebo — hence its title: «safe but not effective». A 2000 review on 9 trials also considers the evidence insufficient, and a trial conducted entirely online with 391 people finds no difference with placebo, with a strong improvement in the placebo group itself. The quality and composition of extracts vary greatly from one study to another: the authors of the largest meta-analysis recommend whole root extracts, which are considered more reliable.
Recommended dosage
400 to 900 mg of aqueous extract before bedtime in most trials. An effect on objective sleep measurements (polysomnography) only appears after repeated intake of at least two weeks, not after a single dose.
Did you know?
Surprisingly: in one study, valerian caused far fewer side effects than the placebo itself (only 3 cases against 18 under placebo), which confirms that it is a particularly well-tolerated plant.
What the studies say
Chez 184 adultes souffrant d'insomnie légère, la combinaison valériane-houblon a entraîné une légère réduction du temps d'endormissement et une amélioration de la qualité de vie physique après 28 jours, sans différence significative avec le placebo sur la plupart des mesures. Aucun effet indésirable grave ni insomnie de rebond n'a été observé à l'arrêt du traitement. Les auteurs concluent à un effet hypnotique modeste mais réel, comparable à celui d'un antihistaminique utilisé comme référence.
Morin CM, Koetter U, Bastien C, Ware JC, Wooten V. — Sleep (2005) — View the source study
Pairs well with
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more