Evidence review
Valerian for Sleep
Valeriana officinalis
The short answer
Early or mixed evidencePossibly a little, but the evidence is mixed. People taking valerian are somewhat more likely to say they slept better, yet in pooled trials it barely changed how fast they fell asleep, and the largest, most rigorous trials found no clear benefit. Any effect builds over two to four weeks, US sleep specialists suggest not using it for chronic insomnia, and cognitive behavioral therapy for insomnia (CBT-I) works better.
7 key studies reviewed
Updated October 12, 2026
Key points
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01
Feels better, measures the same
Reviews find people on valerian more likely to report better sleep, but in an 18-trial analysis time to fall asleep differed from placebo by less than a minute.
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02
Rigorous trials mostly negative
The larger, better-designed trials, including 405 Norwegian adults with insomnia and 227 people having cancer treatment, found no significant benefit on their main sleep measures.
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03
Two to four weeks, not tonight
EMA says valerian is not suitable for same-night relief and recommends 2–4 weeks of nightly use, with a doctor or pharmacist visit if sleep is no better after 2 weeks.
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04
CBT-I comes first
The American Academy of Sleep Medicine strongly recommends CBT-I for chronic insomnia and suggests clinicians not use valerian. No trial has compared the two directly.
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05
Not addictive, but additive
Dependence has not been clearly shown, but withdrawal is reported after long use. Valerian can add to the drowsiness of alcohol, benzodiazepines, and other sedatives.
Valerian may help some people feel they sleep a little better, but the evidence is mixed, and any effect is small and slow to appear. When researchers pool the trials, people taking valerian are more likely than those taking a placebo (dummy pill) to say their sleep improved, yet the time it takes them to fall asleep barely changes, and the largest and most carefully run trials found no clear benefit on their main measures. The American Academy of Sleep Medicine (AASM) suggests that clinicians not use valerian for chronic insomnia, while Europe’s medicines regulator accepts specific valerian extracts for mild nervous tension and sleep disorders. Either way, valerian is not a same-night sleeping pill. European guidance says it needs two to four weeks of nightly use, and cognitive behavioral therapy for insomnia (CBT-I), a structured talking and behavior-change treatment, is the recommended first treatment for long-term insomnia.
Valerian (Valeriana officinalis) is a tall meadow plant whose dried root and rhizome (underground stem) have been used as medicine since the time of ancient Greece and Rome; the US Office of Dietary Supplements (ODS) notes that Galen prescribed it for insomnia in the second century. Today it is one of the most widely sold herbal sleep aids. In the United States it is a dietary supplement, which the Food and Drug Administration does not approve before sale. In the European Union, the Committee on Herbal Medicinal Products (HMPC) of the European Medicines Agency (EMA) accepts dry extracts of the root made with 40–70% ethanol as well-established medicines “for the relief of mild nervous tension and sleep disorders,” based on clinical studies, and accepts teas, tinctures, and other preparations only on the basis of long traditional use. Insomnia means trouble falling asleep, staying asleep, or getting good quality sleep despite the chance to sleep; the US National Heart, Lung, and Blood Institute (NHLBI) calls it chronic when it happens three or more nights a week for more than three months and cannot be fully explained by another health problem.
This page goes through the meta-analyses (studies that pool the results of several trials), the main trials with the products and doses they tested and who paid for them, and why regulators and sleep specialists read the same evidence differently. It then covers how valerian is taken, how long to give it, how it compares with CBT-I, and the safety questions people most often ask: side effects, morning grogginess, whether it is addictive, and whether it can be combined with alcohol or benzodiazepines. Nothing here is medical advice. Poor sleep is a symptom with many causes, including sleep apnea, depression, anxiety, restless legs, pain, and medicines, and those causes need their own diagnosis and treatment, which a herbal sedative can delay.
02 The trials
Key studies
The trials and reviews that carry the most weight for this question, with the product and dose each one tested. Results apply to the preparation studied.
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Shinjyo et al., 2020
Systematic review of 60 studies, with a meta-analysis of 10 placebo-controlled trials
- Who
- 6,894 in the review; 1,065 in the sleep-quality meta-analysis
- What and how much
- Valerian root extracts or dried whole root and rhizome, in varied doses
- How long
- Repeated nightly use; trial lengths varied
Pooled sleep-quality effect 0.36 (95% CI −0.08 to 0.81), not statistically significant, with high heterogeneity (I² 85%) and signs of missing studies; whole-root trials 0.83 (0.03 to 1.62), extracts 0.10 (−0.02 to 0.22). No outside funding.
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Fernández-San-Martín et al., 2010
Meta-analysis of 18 randomized placebo-controlled trials
- Who
- People with insomnia (total not given in the abstract)
- What and how much
- Various valerian preparations
- How long
- Varied between trials
More people reported improved sleep on valerian (relative risk 1.37, 1.05 to 1.78), but time to fall asleep differed by 0.70 minutes (−3.44 to 4.83) and sleep-quality scales by −0.02 (−0.35 to 0.31): a subjective benefit only.
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Bent et al., 2006
Systematic review and meta-analysis of 16 randomized placebo-controlled trials
- Who
- 1,093 patients
- What and how much
- Valerian preparations and doses that varied considerably
- How long
- Varied between trials
In the 6 studies with a yes-or-no sleep quality outcome, valerian raised the chance of improved sleep (relative risk 1.8, 1.2 to 2.9), but with evidence of publication bias; most studies had significant methodological problems.
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Oxman et al., 2007
Randomized, double-blind, placebo-controlled, run by television and internet
- Who
- 405 adults aged 18–75 with insomnia (Norway)
- What and how much
- Valerina Forte coated tablets, three 200 mg extract tablets (600 mg) about an hour before bed
- How long
- 2 weeks
A meaningful improvement in sleep quality occurred in 29% on valerian versus 21% on placebo (p = 0.08, not significant); 5.5% more rated their sleep better on a global question (p = 0.04). Publicly funded.
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Barton et al., 2011
Phase III randomized, double-blind, placebo-controlled (NCCTG N01C5)
- Who
- 227 adults having cancer treatment; 119 evaluable for the main outcome
- What and how much
- 450 mg ground raw valerian root standardized to 0.8% valerenic acid, 1 hour before bed
- How long
- 8 weeks
No difference in Pittsburgh Sleep Quality Index scores (51.4 versus 49.7, P = 0.70); exploratory analyses favored valerian for fatigue. Funded by US Public Health Service cancer research grants.
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Chandra Shekhar et al., 2024
Randomized, double-blind, placebo-controlled; manufacturer-funded
- Who
- 80 adults aged 18–50 with sleep complaints (72 completed; India)
- What and how much
- Sleeproot, a 200 mg capsule of spray-dried hydroalcoholic valerian extract (2% valerenic acid), 1 hour before bed
- How long
- 8 weeks
Sleep quality scores, wrist-tracker sleep latency and sleep time, and lab sleep measures in a 40-person subset improved more than with placebo (p < 0.05). Funded by OmniActive Health Technologies, the extract’s maker.
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Taibi et al., 2009
Phase 2 randomized, double-blind, placebo-controlled crossover
- Who
- 16 women with insomnia, average age 69
- What and how much
- 300 mg concentrated valerian extract, 30 minutes before bed
- How long
- 2 weeks on each treatment
No difference from placebo after one dose or two weeks in sleep latency, time awake, sleep efficiency, or self-rated quality, in the sleep lab or at home. No author financial conflicts.
03 Evidence
What the research shows
Our rating for Valerian for Sleep, based on the studies below.
Meta-analyses agree on one pattern: valerian looks better on questions about how people feel they slept than on measurements of sleep. Bent and colleagues at the University of California, San Francisco (American Journal of Medicine 2006) found 16 placebo-controlled trials with 1,093 patients. Most had significant methodological problems, and doses, preparations, and treatment lengths varied considerably. Six studies asked simply whether sleep improved, and valerian raised the chance of a yes (relative risk 1.8; 95% confidence interval, the range in which the true effect probably lies, 1.2 to 2.9), but there was evidence of publication bias, meaning negative studies may have gone unpublished. Taibi and colleagues (Sleep Medicine Reviews 2007) examined 29 controlled trials, found that most showed no difference from placebo, and noted that none of the most recent and rigorous ones found a significant effect. Fernández-San-Martín and colleagues (Sleep Medicine 2010) pooled 18 trials: people were more likely to report improved sleep on valerian (relative risk 1.37, 1.05 to 1.78), but time to fall asleep differed by just 0.70 minutes (−3.44 to 4.83) and sleep-quality rating scales did not differ at all (−0.02, −0.35 to 0.31). They concluded that the benefit had not been shown with quantitative or objective measures.
Broader reviews have not changed the picture. Leach and Page (Sleep Medicine Reviews 2015) included 14 randomized trials with 1,602 people with insomnia, testing valerian, chamomile, kava, and a Chinese preparation called wuling, and found no statistically significant difference between any herb and placebo on any of 13 measures of effectiveness; valerian trials also recorded more adverse events per person than placebo. Shinjyo and colleagues (Journal of Evidence-Based Integrative Medicine 2020), who received no outside funding, reviewed 60 studies with 6,894 participants and concluded that valerian “could be a safe and effective herb.” Their own meta-analysis of 10 placebo-controlled trials (1,065 people), however, produced a pooled effect on sleep quality of 0.36 (−0.08 to 0.81), which was not statistically significant, with very high heterogeneity (I² 85%, meaning the trials disagreed far more than chance would explain) and signs of missing studies. Trials of dried whole root did better (0.83, 0.03 to 1.62) than trials of extracts (0.10, −0.02 to 0.22), which the authors took as a sign that product quality explains the inconsistency. The most recent overview, an umbrella review of eight systematic reviews by Valente and colleagues (European Neuropsychopharmacology 2024), found no evidence that valerian works for insomnia, apart from subjective improvements in sleep quality, and described the trials as few, varied, and of low methodological quality.
The largest independent trials were negative or borderline. Oxman and colleagues (PLoS One 2007), funded by the Norwegian Knowledge Centre for the Health Services, recruited viewers of a national TV health program and randomized 405 adults with insomnia to 600 mg of a valerian extract (Valerina Forte) or placebo nightly for two weeks. A meaningful improvement in self-rated sleep quality occurred in 29% on valerian and 21% on placebo, a difference that was not statistically significant (p = 0.08), though 5.5% more on valerian rated their sleep better or much better on a final global question (p = 0.04). The authors concluded that valerian has “modest beneficial effects at most.” Jacobs and colleagues (Medicine 2005) ran a similar internet trial in 391 adults with anxiety and insomnia; after four weeks insomnia scores improved as much on placebo as on valerian. In people undergoing cancer treatment, Barton and colleagues (Journal of Supportive Oncology 2011) randomized 227 patients to 450 mg of ground valerian root standardized to 0.8% valerenic acid or placebo for eight weeks; among the 119 who could be evaluated, sleep quality scores did not differ (P = 0.70), although exploratory analyses favored valerian for fatigue. In a small sleep-laboratory crossover trial, Taibi and colleagues (Sleep Medicine 2009) gave 16 older women with insomnia 300 mg of a concentrated extract or placebo for two weeks each and found no difference on any measure of sleep, recorded in the laboratory or at home.
Positive trials exist, mostly with specific European extracts or with manufacturer funding, and they are the basis of EMA’s more favorable view. In a German trial summarized in EMA’s 2016 assessment report, Vorbach and colleagues (1996) gave 121 patients with insomnia 600 mg of an ethanol extract or placebo for 28 days; 55.9% versus 25.9% rated themselves much or very much better, and the gap widened between weeks 2 and 4, though the authors defined no main outcome and called the results exploratory. Ziegler and colleagues (European Journal of Medical Research 2002) randomized 202 outpatients to 600 mg of the extract LI 156 or 10 mg of the benzodiazepine oxazepam for six weeks and reported that valerian was at least as effective, with adverse events in 28.4% versus 36.0%; there was no placebo group, so both groups’ improvement may partly reflect the placebo effect. Most recently, Chandra Shekhar and colleagues (Advances in Therapy 2024) randomized 80 adults aged 18 to 50 with sleep complaints to a 200 mg capsule of a spray-dried valerian extract (Sleeproot) or placebo for eight weeks and reported better sleep-quality scores, shorter sleep latency on wrist trackers, and better sleep-laboratory results in a subset; the study was funded by OmniActive Health Technologies, which makes the extract. EMA’s assessors set aside the Bent meta-analysis because it mixed single-herb and combination products, and discounted the Taibi and Barton trials because of their products, doses, and populations.
Guideline writers take the stricter view. The AASM’s 2017 guideline on drugs for chronic insomnia (Sateia and colleagues, Journal of Clinical Sleep Medicine) suggests that clinicians not use valerian for trouble falling or staying asleep in adults, a weak recommendation that the guideline says reflects lower certainty rather than proof of ineffectiveness. Its 2021 guideline on behavioral treatments (Edinger and colleagues) makes a strong recommendation for multicomponent CBT-I, which combines techniques such as stimulus control (using the bed only for sleep), sleep restriction (limiting time in bed to time asleep), relaxation, and changing unhelpful thoughts about sleep. Searches of PubMed for this page in October 2026 found no trial comparing valerian directly with CBT-I. The National Center for Complementary and Integrative Health (NCCIH) calls the sleep evidence inconsistent and says there is not enough evidence to determine whether valerian is useful for any condition. Open questions include which constituents matter (EMA says the effects “cannot be attributed with certainty to any known constituents”), how much products differ, and whether longer use helps; long-term trials have not been done, and EMA began a periodic review of its valerian monograph with a call for new data in February 2025.
04 In practice
How it was taken in studies
Trials used a range of products, which is part of why their results differ. Oxman’s trial used three 200 mg extract tablets (600 mg) about an hour before bed, Barton’s 450 mg of ground root, Taibi’s 300 mg of a concentrated extract, Ziegler’s and Vorbach’s 600 mg of an ethanol extract, and Chandra Shekhar’s one 200 mg capsule. EMA’s well-established-use monograph covers dry extracts made with 40–70% ethanol (drug-to-extract ratio 3–7.4:1) at 400–600 mg per dose for adolescents, adults, and older people: for sleep problems, one dose half an hour to an hour before bedtime, with an earlier dose during the evening if needed, and no more than four doses a day. For traditional use it gives, among other preparations, a tea of 0.3–3 g of dried, cut root in 150 ml of boiling water, taken half an hour to an hour before bed. NCCIH notes that 300–600 mg a day has been used with apparent safety for up to six weeks and that the safety of longer use is unknown.
Valerian works gradually, if at all. EMA says that because of its gradual onset it is not suitable for acute treatment, that continued use over two to four weeks is recommended for the best effect, and that a doctor or pharmacist should be consulted if symptoms persist or worsen after two weeks. Taking a capsule on a bad night and judging it the next morning is therefore not a fair test, and keeping a simple sleep diary for a week before and during use gives a clearer answer than memory. Products vary widely. ODS notes that constituent levels differ with harvest time and that supplements are not always tested for consistency between batches, and a label that says only “valerian 500 mg” does not say whether that is raw root or concentrated extract. Valerian is often combined with hops, lemon balm, or passionflower, which makes it harder to know what is helping and adds to drowsiness.
For insomnia lasting months, valerian is best seen, at most, as an add-on to CBT-I rather than a substitute. CBT-I takes several weeks of practice, and the AASM recommends it on a strong level of evidence, with briefer multicomponent versions as a conditional option; good sleep habits alone are not enough, and the AASM suggests not relying on sleep hygiene as a stand-alone treatment. The AASM’s 2017 guideline also suggests several prescription medicines for some adults when medication is needed, and those choices are best made with a clinician. Valerian tea is a less defined exposure than the extracts tested in trials, and its strong smell, which ODS notes many people find unpleasant, puts some people off.
05 Caution
Before you try valerian
Side effects in trials have mostly been mild. EMA lists gastrointestinal symptoms such as nausea and abdominal cramps, frequency unknown, and NCCIH adds headache, stomach upset, mental dullness, excitability, uneasiness, and vivid dreams. ODS reports that headaches, dizziness, itching, and digestive upsets were the most common effects in trials but occurred about as often with placebo, while Leach and Page found more adverse events per person with valerian than with placebo. Morning grogginess depends on dose: in an early trial summarized by ODS and EMA, people felt sleepier the next morning after 900 mg of an aqueous extract, whereas a trial in 102 volunteers found no next-morning effect on reaction time or concentration after 600 mg of an ethanol extract. EMA’s assessment report also describes reduced vigilance one to two hours after a dose of a liquid preparation. EMA warns that valerian may impair the ability to drive or use machines, so do not drive until you know how it affects you. About 20 g of valerian root taken in an overdose caused fatigue, cramps, chest tightness, light-headedness, tremor, and dilated pupils that resolved within 24 hours.
LiverTox, the NIH database on drug-induced liver injury, says valerian has been linked to rare instances of clinically apparent liver injury, and NCCIH notes that the very rare cases mostly involved products combining valerian with other herbs. Memorial Sloan Kettering Cancer Center (MSKCC) describes two cases in women that resolved after stopping, and advises people with liver, pancreatic, or gallbladder disease to avoid valerian. Stop it and see a doctor promptly for yellow skin or eyes, dark urine, pale stools, or persistent nausea. Valerian is not considered addictive in the way benzodiazepines are: EMA’s assessors found no clear reports of dependence and judged the few withdrawal case reports not to suggest an abuse risk, given how widely valerian is used. Withdrawal can still happen. NCCIH says stopping abruptly after long use may cause anxiety, irritability, heart disturbances, insomnia, and rarely hallucinations, and in a case published in JAMA in 1998 a 58-year-old man who had taken 2.5–10 g of valerian extract daily for years developed heart complications and delirium after stopping. After months of nightly use, taper gradually. MSKCC advises stopping at least a week before surgery because valerian may interact with anesthesia, so plan that taper with your surgical team.
The main interaction risk is extra sedation. NCCIH says valerian should not be taken with alcohol or sedatives, ODS warns of additive effects with benzodiazepines such as alprazolam (Xanax), diazepam (Valium), and lorazepam (Ativan), with barbiturates and opioids, and with sedating supplements such as kava, melatonin, and St. John’s wort, and MSKCC says valerian lengthens the sedation of benzodiazepines and other central nervous system drugs. In one case report, a man taking lorazepam developed hand tremor, dizziness, and muscle fatigue after adding valerian and passionflower. EMA lists no interactions for its registered medicines, and its assessors note that studies of valerian combinations found no extra effect with alcohol, unlike benzodiazepines; the cautious course is still to avoid alcohol. Valerian appears to have little effect on drug-metabolizing liver enzymes: in a study summarized by EMA, two weeks of 1,000 mg extract daily raised the peak level of alprazolam only slightly (25 to 31 ng/ml), which the authors judged not clinically relevant. Never stop a benzodiazepine or Z-drug such as zolpidem, or swap it for valerian, without a tapering plan from the prescriber.
EMA does not recommend valerian during pregnancy or breastfeeding because safety has not been established, and NCCIH says little is known. EMA’s report notes that 98 women in a Swedish birth register who used valerian in early pregnancy had babies without increased problems, while MSKCC cites animal studies suggesting effects on fetal brain development; that is too little evidence to call it safe. EMA does not recommend valerian under 12 years, and sleep problems in children need a pediatrician’s assessment, because they can reflect conditions such as ADHD or developmental and school problems. Some sleep problems need a doctor rather than a herb. Loud snoring, gasping, or pauses in breathing during sleep, especially with daytime sleepiness, suggest sleep apnea, which a sedative can mask; insomnia with low mood, loss of interest, or anxiety may be depression or an anxiety disorder; and thoughts of suicide or self-harm need urgent help from emergency services or a crisis line. Insomnia that has lasted more than three months, new sleep problems with falls or confusion in an older person, and sleep disturbed by pain, breathlessness, or frequent urination also deserve a medical assessment.
06 Questions
Frequently Asked Questions
The evidence is mixed. In pooled trials, people taking valerian are somewhat more likely to say they slept better, but time to fall asleep barely changes, and the largest independent trials found no clear benefit. The American Academy of Sleep Medicine suggests clinicians not use it for chronic insomnia, while Europe accepts specific extracts for mild nervous tension and sleep disorders. Other calming herbs such as passionflower and chamomile have limited evidence too. For insomnia lasting months, CBT-I is the recommended first treatment.
Longer than most people expect. The European Medicines Agency says valerian acts gradually, is not suitable for same-night relief, and works best with two to four weeks of nightly use. In one German trial the difference from placebo grew between weeks 2 and 4. If your sleep has not improved, or is getting worse, after two weeks, the agency advises talking to a doctor or pharmacist. Keeping a sleep diary before and during use is the best way to judge whether it is helping.
It depends on the product. European registered medicines use 400 to 600 mg of a dry ethanol extract half an hour to an hour before bed, with an earlier evening dose if needed and no more than four doses a day. As a traditional tea, 0.3 to 3 g of dried root is steeped in 150 ml of boiling water. Trials used 200 to 600 mg of various extracts or 450 mg of ground root. NCCIH notes that 300 to 600 mg a day has been used with apparent safety for up to six weeks.
Most are mild: nausea or stomach cramps, headache, dizziness, mental dullness, uneasiness, and vivid dreams. Higher doses can leave some people groggy the next morning, and the European Medicines Agency warns that valerian may impair driving. Liver injury has been reported in rare cases, mostly with multi-herb products, so stop and see a doctor if you notice yellow skin or eyes or dark urine. Stopping suddenly after long, regular use can cause withdrawal symptoms such as anxiety, irritability, and poor sleep.
It is not considered addictive the way benzodiazepines are. European regulators found no clear reports of dependence despite very wide use. Withdrawal has still been reported: NCCIH says stopping abruptly after long use may cause anxiety, irritability, heart disturbances, insomnia, and rarely hallucinations, and one man who took large daily doses for years developed heart problems and delirium after stopping. If you have taken valerian nightly for months, reduce it gradually, and tell your care team before any surgery.
It is best avoided unless your prescriber agrees. Valerian can add to the sedation of benzodiazepines such as alprazolam, diazepam, and lorazepam, as well as Z-drugs, opioids, and alcohol, and one man on lorazepam developed tremor and dizziness after adding valerian and passionflower. NCCIH advises against combining valerian with alcohol or sedatives. Never stop a benzodiazepine or replace it with valerian without a tapering plan from the doctor who prescribed it.
07 References
Sources
These references support the claims on this page. They are not an endorsement of any product. The valerian monograph carries its own full source list.
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Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline
Journal of Clinical Sleep Medicine (PubMed 27998379), 2017
Sateia et al.: GRADE-based guideline; suggests clinicians not use valerian for sleep onset or sleep maintenance insomnia in adults (weak); weak recommendations reflect lower certainty, not proof of ineffectiveness.
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Behavioral and psychological treatments for chronic insomnia disorder in adults: an American Academy of Sleep Medicine clinical practice guideline
Journal of Clinical Sleep Medicine (PubMed 33164742), 2021
Edinger et al.: strong recommendation for multicomponent CBT-I in chronic insomnia; conditional recommendations for stimulus control, sleep restriction, and relaxation; suggests not using sleep hygiene alone.
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Herbal medicine for insomnia: A systematic review and meta-analysis
Sleep Medicine Reviews (PubMed 25644982), 2015
Leach and Page: 14 RCTs, 1,602 people with insomnia; valerian, chamomile, kava, and wuling; no difference from placebo on any of 13 efficacy measures; more adverse events per person with valerian.
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Does valerian work for insomnia? An umbrella review of the evidence
European Neuropsychopharmacology (PubMed 38359657), 2024
Valente et al.: 8 systematic reviews; good safety profile but no evidence of efficacy for insomnia beyond subjective sleep quality; few, heterogeneous, low-quality trials; no competing interests.
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Valerian Root in Treating Sleep Problems and Associated Disorders—A Systematic Review and Meta-Analysis
Journal of Evidence-Based Integrative Medicine (PubMed 33086877), 2020
Shinjyo, Waddell, Green: 60 studies, 6,894 participants; sleep-quality meta-analysis of 10 RCTs, effect 0.36 (−0.08 to 0.81), I² 85%; whole root 0.83, extracts 0.10; no severe adverse events; no funding or conflicts (full text).
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Effectiveness of Valerian on insomnia: a meta-analysis of randomized placebo-controlled trials
Sleep Medicine (PubMed 20347389), 2010
Fernández-San-Martín et al.: 18 RCTs; subjective improvement RR 1.37 (1.05–1.78); sleep latency difference 0.70 minutes (−3.44 to 4.83); sleep-quality scale SMD −0.02; benefit not shown with objective measures.
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Valerian for sleep: a systematic review and meta-analysis
American Journal of Medicine (PubMed 17145239), 2006
Bent et al.: 16 placebo-controlled trials, 1,093 patients; RR 1.8 (1.2–2.9) for improved sleep in 6 studies, with evidence of publication bias; most studies methodologically flawed.
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A televised, web-based randomised trial of an herbal remedy (valerian) for insomnia
PLoS One (PubMed 17940604), 2007
Oxman et al.: 405 adults, Valerina Forte 3 × 200 mg extract nightly for 2 weeks; improvement 29% vs 21% (p = 0.08); global improvement +5.5% (p = 0.04); funded by the Norwegian Knowledge Centre for the Health Services (full text).
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The use of Valeriana officinalis (Valerian) in improving sleep in patients who are undergoing treatment for cancer: a phase III randomized, placebo-controlled, double-blind study (NCCTG Trial, N01C5)
Journal of Supportive Oncology (PubMed 21399726), 2011
Barton et al.: 227 randomized, 119 evaluable; 450 mg ground root (0.8% valerenic acid) for 8 weeks; PSQI AUC 51.4 vs 49.7 (P = 0.70); exploratory fatigue benefit; Public Health Service grants (full text).
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European Union herbal monograph on Valeriana officinalis L., radix
European Medicines Agency (EMA/HMPC/150848/2015), 2016
Adopted 2 February 2016: well-established use of 40–70% ethanol dry extract, 400–600 mg, for mild nervous tension and sleep disorders; 2–4 weeks for effect; see a doctor after 2 weeks; tea 0.3–3 g; not under 12, in pregnancy, or lactation; may impair driving; 20 g overdose.
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Assessment report on Valeriana officinalis L., radix and Valeriana officinalis L., aetheroleum
European Medicines Agency (EMA/HMPC/150846/2015), 2016
Trial summaries (Vorbach, Ziegler, Donath, Leathwood, Kuhlmann); critiques of Bent, Taibi, and Barton; gradual onset over 2–4 weeks; no clear dependence; Garges withdrawal case; alprazolam study; Swedish pregnancy register; no alcohol synergy in combination studies.
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Valerian: Usefulness and Safety
National Center for Complementary and Integrative Health (NIH), 2025
Updated May 2025: inconsistent sleep evidence; AASM recommended against use for chronic insomnia; 300–600 mg daily up to 6 weeks apparently safe; side effects; withdrawal after abrupt stopping; very rare liver injury; avoid with alcohol or sedatives.
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Valerian: Fact Sheet for Health Professionals
NIH Office of Dietary Supplements, 2013
Updated March 2013: sleep evidence inconclusive; Galen used it for insomnia; no agreement on active constituents; variable product composition; common trial side effects similar to placebo; additive effects with benzodiazepines, barbiturates, kava, and melatonin.
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Valerian
LiverTox, National Institute of Diabetes and Digestive and Kidney Diseases (PubMed 31643579), 2020
Updated April 2020: valerian has been linked to rare instances of clinically apparent liver injury.
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Valerian
Memorial Sloan Kettering Cancer Center, About Herbs, 2023
Stop at least a week before surgery; lengthens sedation from benzodiazepines and other CNS drugs; two hepatotoxicity cases; avoid with liver, pancreatic, or gallbladder disease; animal data on fetal brain; lorazepam case report.
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Insomnia: What Is Insomnia?
National Heart, Lung, and Blood Institute (NIH), 2022
Defines insomnia and chronic insomnia (3 or more nights a week for more than 3 months, not fully explained by another health problem); lists CBT-I among treatments.