Research review
Valerian root vs ashwagandha: what the evidence says about each
Valerian's largest sleep reviews disagree with each other and its one anxiety-disorder trial found no benefit over placebo. Ashwagandha's sleep trials are smaller and used either an extract at an unconfirmed dose or a much higher root-powder dose than a typical capsule, in older men with diagnosed insomnia. No trial has compared the two directly.
The evidence doesn't support ranking valerian root above or below ashwagandha for sleep or anxiety — no trial has compared the two directly. What exists instead are two separate, imperfect literatures: valerian's largest reviews disagree with each other on sleep, and its one anxiety-disorder trial found nothing; ashwagandha's sleep trials are smaller and used doses well above a typical capsule.
What the evidence doesn't support
It doesn't support a head-to-head comparison, because none has been run. It doesn't support treating either one as a treatment for insomnia, generalized anxiety disorder, or any other diagnosed condition. And it doesn't support assuming a standard capsule dose of either ingredient performs the way the higher or differently formulated doses used in some of the trials below did.
What the trials found
Valerian's sleep evidence is a genuinely split field. A 2006 meta-analysis of 16 trials (1,093 people) found a modest, statistically significant benefit on a simple yes/no sleep-improvement measure, but flagged evidence of publication bias in that result, with trial doses ranging widely from 225 to 1,215 mg a day (PMID 17145239). A 2020 review pooling 10 trials with numeric sleep-quality outcomes found a small, not-statistically-significant effect overall (PMID 33086877). A 2024 umbrella review of 8 systematic reviews concluded valerian has a good safety profile but no empirical support for insomnia by objective measures. On anxiety specifically, a Cochrane review found only one eligible trial — 36 people with generalized anxiety disorder, over 4 weeks — and it showed no significant difference between valerian and placebo (PMID 17054208).
Ashwagandha's sleep evidence comes from two smaller trials, each with its own caveat. An 8-week, double-blind, placebo-controlled trial of 80 adults — 40 healthy, 40 with diagnosed insomnia — found a root extract improved sleep-onset latency, total sleep time, and sleep efficiency versus placebo, more so in the insomnia group, though the exact daily dose isn't stated in the published abstract (PMID 32818573). A separate 30-day trial gave 27 elderly men with diagnosed primary insomnia 6 grams a day of root powder at night; sleep-quality scores improved substantially against their own baseline, but there was no placebo group to rule out other explanations, and 6 g/day is roughly 4.6 times a typical 1,300 mg/day root-powder capsule dose (PMID 35370376). On stress and anxiety more broadly (not a diagnosed anxiety disorder), a meta-analysis of 9 trials, 558 people, found ashwagandha reduced perceived-stress and anxiety-scale scores, and cortisol, versus placebo (PMID 39348746) — a different population and outcome than valerian's single, null anxiety-disorder trial.
On mechanism, laboratory research on valerian points to valerenic acid slowing the breakdown of GABA, a calming brain chemical — a proposed mechanism, not proof of effect in people (PMID 10411208). No equivalent GABA-mechanism data for ashwagandha turned up in the trials reviewed here.
| Ingredient | Best sleep evidence | Best anxiety/stress evidence | Note |
|---|---|---|---|
| Valerian root | 16-trial and 10-trial meta-analyses that disagree with each other; no benefit on objective measures per 2024 umbrella review | One trial (36 people, diagnosed GAD): no significant benefit | Trial doses 225-1,215 mg/day |
| Ashwagandha | Two trials: extract (dose unconfirmed) and 6 g/day root powder, elderly men with insomnia, no placebo arm | 9-trial meta-analysis (558 people, broader stress/anxiety population): reduced stress, anxiety scores, cortisol | Sleep-trial dose is 4.6x a typical capsule |
| Head-to-head trial | None exists | ||
Questions people ask
Which is better, valerian root or ashwagandha, for sleep?
No trial has compared them. Valerian's largest reviews disagree with each other and found no benefit on objective sleep measures overall; ashwagandha's two sleep trials showed improvement but used a higher root-powder dose or an unconfirmed extract dose, in a population that included diagnosed insomnia.
Which is better, valerian root or ashwagandha, for anxiety?
Valerian's one trial in a diagnosed anxiety disorder found no benefit over placebo. Ashwagandha's evidence is a 9-trial meta-analysis of broader stress and anxiety (not a diagnosed disorder specifically) that found a reduction versus placebo. These aren't directly comparable populations or outcomes, and no trial has tested the two against each other.
Valerian root vs ashwagandha and GABA?
Laboratory research on valerian describes a GABA-related mechanism (valerenic acid slowing GABA breakdown). No comparable GABA-mechanism research on ashwagandha turned up in the trials reviewed here.
Can you take valerian root and ashwagandha together?
That's answered separately at valerian root and ashwagandha: what the evidence says — no trial has tested the combination.
When to talk to a doctor
Ongoing trouble sleeping or an anxiety disorder that interferes with daily life is worth raising with a doctor. Neither valerian root nor ashwagandha is a treatment for insomnia, generalized anxiety disorder, or any other diagnosed condition. Ashwagandha in particular carries its own cautions — pregnancy, nursing, thyroid conditions, and liver concerns among them (see who shouldn't take ashwagandha) — and valerian shouldn't be combined with a sedating medication without asking a doctor first (see valerian root and medications: what to check).
Sources
- Valerian for sleep: a systematic review and meta-analysis A 2006 meta-analysis of 16 trials found a modest benefit for valerian on a simple yes/no sleep-quality measure, but flagged publication bias, wide dose variation (225-1,215 mg/day), and no significant difference in side effects versus placebo.
- Valerian Root in Treating Sleep Problems and Associated Disorders-A Systematic Review and Meta-Analysis A 2020 systematic review of 60 studies found a small, not-statistically-significant pooled effect of valerian on sleep quality overall, a higher (but still uncertain) effect for whole root versus extract, and high heterogeneity in its anxiety meta-analysis; individual trial results ranged from no effect to modest subjective improvement.
- Valerian for anxiety disorders A Cochrane review found only one small trial (36 people, 4 weeks) testing valerian for a diagnosed anxiety disorder; it showed no significant difference from placebo on the main anxiety scale, too little evidence to draw a conclusion either way.
- Clinical evaluation of the pharmacological impact of ashwagandha root extract on sleep in healthy volunteers and insomnia patients: A double-blind, randomized, parallel-group, placebo-controlled study In 80 adults (half healthy, half with diagnosed insomnia), a root extract improved several sleep measures versus placebo over 8 weeks, more so in those with insomnia.
- Efficacy of Brimhana Nasya and Ashwagandha (Withania somnifera (L.) Dunal) root powder in primary insomnia in elderly male: A randomized open-label clinical study In 27 elderly men with diagnosed insomnia, 6 g/day of ashwagandha root powder for 4 weeks improved self-reported sleep versus their own baseline, with no placebo group.
- Effects of Ashwagandha (Withania Somnifera) on stress and anxiety: A systematic review and meta-analysis Pooling 9 trials in 558 people, ashwagandha lowered perceived stress, anxiety-scale scores and cortisol more than placebo.
- The scientific basis for the reputed activity of Valerian A pharmacology review describes laboratory evidence that valerenic acid, one of valerian's compounds, slows the breakdown of GABA, a proposed mechanism for its traditional sedative reputation — laboratory-level evidence, not proof of effect in people.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.