Supplement evidence
Valerian
A good safety record and an unconvincing efficacy record.
What Its Legal Status Actually Means
Read this before anything below it. Legal to sell is not the same fact as reviewed, verified, or approved.
Valerian is sold in the United States as a dietary supplement under DSHEA, so it needs no FDA review of efficacy, safety, or potency before sale, and it has never been FDA-approved to treat insomnia, anxiety, or anything else. Valerian oil and extract are separately listed as generally recognised as safe for use as food flavourings, which is a statement about flavouring quantities and not an endorsement of therapeutic doses. In Europe the EMA has issued a herbal monograph covering traditional use for mild nervous tension and sleep, a category based on longstanding use rather than proof of efficacy. Because it is a supplement, no authority verifies what is in the bottle: preparations differ enormously between whole root or rhizome and alcoholic or aqueous extracts, several of the active constituents (notably the valepotriates and valerenic acid) are chemically unstable and degrade on the shelf, and the published trials used doses, extracts, and treatment lengths that vary so widely they cannot be compared cleanly.
Quoted whole from the 2026-08-18 study harvest. Not summarized, not shortened.
What the Research Shows
5 records from the 2026-08-18 harvest, each checked against PubMed and Europe PMC on that date. How a study was designed, how many people were in it, and who paid for it are printed above what it found, because those three facts decide how much the finding is worth.
Study 1 · 2006
- Meta-analysis of randomized trials
- 1,093 participants
- Reputable journal
- Independently funded
gold standard85/100Top of the evidence hierarchy, independently funded.
Read this first: The high trust score reflects the quality of this meta-analysis as a piece of evidence synthesis, not the strength of the effect it found. The pooled benefit rests on a subjective, dichotomised outcome in six trials with demonstrated publication bias, and the authors' own conclusion is the hedged "valerian might improve sleep quality," followed by a call for better studies. Twenty years on, those studies have largely not materialised.
Sixteen randomised placebo-controlled trials in 1,093 patients produced one pooled estimate: among the six trials that reported sleep quality as improved-or-not, people taking valerian were more likely to report improvement (relative risk 1.8, 95% CI 1.2-2.9). The authors immediately qualify it — most of the trials had significant methodological problems, doses and preparations varied considerably, and there was evidence of publication bias in that very summary measure, meaning negative trials are likely missing from the literature.
How this record was checked
PubMed record 17145239 fetched via NCBI efetch 2026-08-18; title, authors, journal, year, DOI, the 16 studies / 1,093 patients count, and the relative risk 1.8 (95% CI 1.2-2.9) confirmed from the abstract. Europe PMC core record fetched 2026-08-18 lists NIH grants K08 AT001338 (NCCIH) and 1 K08 ATO1338-01 (PHS HHS), hence funding INDEPENDENT; the Europe PMC full text for PMC4394901 is not deposited (404), so no conflict-of-interest statement could be read and conflicts is recorded false.
Study 2 · 2007
- Systematic review of randomized trials
- Reputable journal
- Independently funded
strong79/100Well-supported by good-quality research.
Read this first: This review reaches the opposite conclusion to Bent 2006 from overlapping trials, and the difference is instructive: Taibi weighted trial quality and recency, and found that the better and newer the study, the smaller the effect. That pattern is the signature of a treatment whose apparent benefit comes from weak methods.
Reviewing 37 studies — 29 controlled trials assessed for efficacy and safety plus eight open-label trials assessed for safety — the authors found that most studies showed no significant difference between valerian and placebo, in healthy sleepers and in people with insomnia alike. Critically, none of the most recent studies, which were also the most methodologically rigorous, found any effect on sleep. The evidence supports valerian being safe with only rare adverse events; it does not support its efficacy as a sleep aid.
How this record was checked
PubMed record 17517355 fetched via NCBI efetch 2026-08-18; title, authors, journal, year, DOI, and the 592 screened / 36 articles describing 37 studies counts confirmed from the abstract. Europe PMC core record fetched 2026-08-18 lists NIH grants P30-NR04001 and T32-NR07039 (NINR) and R21-AT-002108 (NCCIH), hence funding INDEPENDENT; no PMC full text is available, so no conflict-of-interest statement could be read and conflicts is recorded false. Total participant N across the 37 studies is not stated in the abstract, so sampleSize is left null rather than guessed.
Study 3 · 2020
- Meta-analysis of randomized trials
- 1,065 participants
- Indexed journal
- No funding reported
- Declared conflicts of interest
strong75/100Well-supported by good-quality research.
Read this first: The abstract's conclusion — that "valerian could be a safe and effective herb to promote sleep" — is not supported by the review's own primary pooled result, whose confidence interval crosses zero. The whole-root subgroup finding that the authors lean on rests on four trials and a confidence interval that nearly touches zero, and it is a post-hoc subgroup analysis, the weakest kind of evidence. One co-author is affiliated with Heartwood Education, a UK herbal-medicine education organisation, so the review is not independent of the herbal-medicine field it evaluates.
This review pooled 10 randomised placebo-controlled trials (n=1,065) for subjective sleep quality and found a combined effect size of 0.36 with a 95% confidence interval of -0.08 to 0.81 — that is, not statistically significant — alongside severe heterogeneity (I-squared 85%) and a funnel plot showing missing studies. The same pattern appeared for anxiety across seven trials, with significant publication bias and I-squared of 93%. The authors attribute the inconsistency to variation in preparation, reporting a larger effect for whole root or rhizome (0.83, 95% CI 0.03-1.62, 4 trials) than for extracts (0.10, 95% CI -0.02 to 0.22, 6 trials).
How this record was checked
PubMed record 33086877 fetched via NCBI efetch 2026-08-18; title, authors, journal, year, DOI, and the 60 studies / n=6,894 and 10 studies / n=1,065 counts confirmed from the abstract. Europe PMC full text (PMC7585905) fetched 2026-08-18: pooled effect 0.36 (95% CI -0.08 to 0.81), I-squared 85.33%, funnel plot indicating missing data, and the whole-root (0.83, 95% CI 0.03-1.62) versus extract (0.10, 95% CI -0.02 to 0.22) subgroup estimates all read directly off the article. Its funding statement reads "The author(s) received no financial support for the research, authorship, and/or publication of this article," hence funding NONE, and the conflicting-interests declaration states none. The Heartwood Education affiliation is taken from the article's own author-affiliation block.
Study 4 · 2017
- Clinical guideline
- Reputable journal
- Funding not established
strong70/100Well-supported by good-quality research.
Read this first: A WEAK GRADE recommendation against a treatment is not a finding that it is dangerous; it means the trials are too few, too small, and too inconsistent to justify recommending it. The guideline also notes that it downgraded evidence quality across the board because most insomnia drug trials are industry-funded and carry publication-bias risk. It is now nine years old.
After a systematic review of randomised trials graded with GRADE, the American Academy of Sleep Medicine issued an explicit recommendation against valerian: "We suggest that clinicians not use valerian as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults." It sits alongside the same negative recommendation for melatonin, diphenhydramine, trazodone, and tryptophan. The recommendation is graded WEAK, which reflects the low certainty of the underlying evidence rather than proof that valerian is harmful.
How this record was checked
PubMed record 27998379 fetched via NCBI efetch 2026-08-18; title, authors, journal, year, DOI, and the verbatim valerian recommendation confirmed from the abstract, as was the guideline's GRADE methodology statement. The two Europe PMC commentCorrection entries are ordinary "Comment in" letters (PMIDs 28416045, 28454603), not corrections or retractions. Full text was not retrievable (Europe PMC returned no body for PMC5263087 and NCBI efetch db=pmc returned abstract only), so neither the funding statement nor the task-force disclosure list could be read: funding UNKNOWN, conflicts false.
Study 5 · 2006
- Systematic review of randomized trials
- 36 participants
- Top-tier journal
- Funding not established
- Preregistered
strong75/100Well-supported by good-quality research.
Read this first: This is a rigorous review of an essentially empty evidence base, and it is now twenty years old. Absence of evidence is not evidence of absence — but people buying valerian for anxiety should know that a full Cochrane search found one 36-person pilot study, and it was negative.
Cochrane reviewers searched the trials registers, contacted study authors and valerian manufacturers, and found exactly one eligible randomised trial: a four-week pilot study of 36 people with generalised anxiety disorder comparing valerian, diazepam, and placebo. Valerian did not differ from placebo on total HAM-A scores or on somatic or psychic factor scores. The reviewers concluded there is insufficient evidence to draw any conclusion about valerian for anxiety disorders.
Miyasaka LS, Atallah AN, Soares BG. (2006). Valerian for anxiety disorders. Cochrane Database of Systematic Reviews. PMID 17054208.
How this record was checked
PubMed record 17054208 fetched via NCBI efetch 2026-08-18; title, authors, journal, year, DOI (CD004515.pub2), the single included RCT, and the N=36 generalised anxiety disorder sample confirmed from the abstract. Europe PMC core record checked 2026-08-18: no grant list and no PMC full text deposited, so the Sources of Support section could not be read and funding is recorded UNKNOWN. Preregistered recorded true because Cochrane reviews are preceded by a published protocol.
The Risks
Nobody checks this purchase the way a prescription is checked. No prescriber reviews it against the rest of what you take, no pharmacist screens the interaction, and no regulator confirms the dose in the capsule before it is sold. That is why this section sits here at full length rather than as a footnote.
What the paragraph below covers:
- Liver injury
- Dependence and withdrawal
- Drug interactions
- Stomach and gut
- Sedation
Valerian's honest problem is not danger but futility: across decades of trials it has a consistently good safety record and a consistently unconvincing efficacy record. The adverse events reported in trials were rare and mild — headache, dizziness, daytime drowsiness, gastrointestinal upset, and occasionally paradoxical excitability — with no serious events across subjects aged 7 to 80 in the largest review. That said, valerian is a sedative and adds to the effect of alcohol, benzodiazepines, opioids, antihistamines, and other central nervous system depressants, so combining them can impair driving and breathing; abrupt discontinuation after long heavy use has been reported to produce benzodiazepine-like withdrawal in isolated cases; occasional hepatotoxicity has been reported, usually with multi-herb products where valerian's role is unclear; and it has not been studied in pregnancy, breastfeeding, or liver disease. The larger risk is practical — someone with genuine chronic insomnia who takes valerian for months is postponing cognitive behavioural therapy for insomnia, which is the first-line treatment with real evidence behind it, and someone whose insomnia is a symptom of depression, anxiety, or sleep apnoea is leaving the actual condition untreated.
What Is Not Known
The boundaries of the section above, in the harvest’s own words. What it excluded, why, and where it looked and found nothing. An absence of evidence is not evidence of absence, and it is not evidence of benefit either.
What Was Left Out, and Why
Quoted from the harvest, where these notes sat above the study list rather than after it. Where a note says “below” it means the studies in the section above.
- Stevinson & Ernst 2000 (Sleep Med, PMID 10767649) excluded as superseded by Bent 2006 and Taibi 2007, which cover the same trials with more of them.
- Multi-herb combination reviews (Sleep Med Rev 25644982; Pharmacol Res 35378276; Evid Based Complement Altern Med 32382286) excluded because they pool valerian with other botanicals and cannot isolate a valerian effect.
- Individual small valerian RCTs excluded in favour of the pooled analyses below.
- Reports of valerian hepatotoxicity are almost all combination products or single case reports; no verifiable systematic review of valerian liver injury alone was found, so none is claimed here.
The Retraction Check
PubMed efetch records for all five PMIDs fetched 2026-08-18 and inspected for "Retraction in", "Erratum", "Expression of concern", and "Withdrawn" flags; none present. Europe PMC correction lists checked; the only entries are two ordinary "Comment in" letters attached to the AASM guideline, not corrections.
Questions for a Prescriber or Pharmacist
This page does not tell anyone to take Valerian or to avoid it. It is not able to: it does not know what else you take, what you have tried, or what you are treating. These are the questions each study above raises, written to be asked out loud.
- The main positive finding for valerian came from six trials that showed signs of publication bias — is it worth my trying it, or should we go straight to something with better evidence for my insomnia?
- The best-designed valerian studies all found no effect on sleep — what treatment for my insomnia actually has evidence behind it?
- The most recent valerian meta-analysis could not show a significant effect on sleep overall — is there any reason to expect the particular product I'd buy to do better?
- The sleep-medicine guideline recommends against valerian for insomnia — what does it recommend instead for someone like me, and does that include CBT for insomnia?
- There is only one small trial of valerian for anxiety and it did not beat placebo — what treatment for anxiety would you actually recommend?
And the one to ask at the counter, whatever the answers above turn out to be: given everything I am already taking, what would you want to know about Valerian before I put it in the same body?
Where This Page Comes From
Transcribed from the study-harvest-2026-08-18 record for valerian, built into this page by scripts/supplement-ingest.mjs on 2026-09-07. Nothing here is fetched at page load, and nothing here was written by a model without a citation behind it.
| Source file | study-harvest/2026-08-18/valerian.yaml |
|---|---|
| Source repo | REPTechnologies/avalo-backend |
| SHA-256 | 8060bc5c1222cb57c7d722ff77608f3c3eb8064eb5e7f3116390815006372c1f |
| Also searched as | Valeriana officinalis, valerian root, all-heal, garden heliotrope, setwall, LI 156, Sedonium |
The Other Substances
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- Microdosing
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- Phenibut
- SAMe
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Do any supplements actually work? asks the question across all of them. The full library has the medication records, the funding investigations, and the glossary.