Valerian is a flowering plant (Valeriana officinalis L.) native to Europe and Asia whose roots and rhizomes (underground stems) are dried and sold as tea, capsules, tablets and liquid extracts. It has been used medicinally since ancient Greece and Rome, and today it is promoted mainly for insomnia, anxiety and stress (NCCIH).
The single most important fact is that the evidence for sleep is inconsistent. In the EU, one type of ethanol extract has “well-established use” status for mild nervous tension and sleep disorders (EMA monograph). In the US, the American Academy of Sleep Medicine (AASM) suggests that clinicians not use valerian for chronic insomnia (Sateia et al., J Clin Sleep Med 2017), and NCCIH says there is not enough evidence to show it is useful for any health condition.
This page summarizes what clinical trials, meta-analyses and regulators report. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Type | Herbal product (dried root and rhizome of Valeriana officinalis L.) |
| Forms | Tea, powdered root, dry and liquid extracts, tinctures |
| Route | Oral (also used as a bath additive in the EU) |
| EU well-established-use dose | 400–600 mg dry ethanol extract per dose; for sleep, 0.5–1 h before bedtime, maximum 4 doses a day (EMA monograph) |
| Doses in trials | 300 mg extract nightly for 2 weeks; 600 mg extract (≈3,600 mg root) nightly for 2 weeks |
| Half-life | Valerenic acid, a marker constituent: 1.1 ± 0.6 h after a single 600 mg dose (n = 6) |
| Proposed mechanism | Valerenic acid enhances GABA-A receptor responses in lab and mouse studies; EMA says effects cannot be attributed with certainty to any known constituent |
| US status | Sold as a dietary supplement (not FDA-approved for any disease); listed as a permitted natural flavoring in food; not a controlled substance |
| WADA status | Not named on the 2026 Prohibited List |
What it is
The EU herbal monograph covers the root of Valeriana officinalis L. and lists many preparations: the cut or powdered root (for tea), juice of the fresh root, water, methanol and ethanol extracts, and tinctures (EMA monograph). These differ a lot in strength, so a “500 mg valerian” label means little unless the preparation is stated.
| Preparation (EMA monograph) | EU status | Single dose |
|---|---|---|
| Dry extract, drug-extract ratio 3–7.4:1, ethanol 40–70% | Well-established use (clinical data) | 400–600 mg |
| Cut or powdered root as tea | Traditional use | 0.3–3 g in 150 mL boiling water |
| Dry extract, water | Traditional use | 420 mg |
| Dry extract, methanol 45% | Traditional use | 144–288 mg or 450 mg, depending on extract |
| Dry extract, ethanol 85% | Traditional use | 322 mg |
Product analyses typically measure two groups of root constituents: valerenic acid with its derivatives, and valepotriates (Shohet et al., Pharmazie 2001). Valerenic acid is a commonly used marker for measuring valerian in products and in blood (Anderson et al., Phytother Res 2005).
Proposed mechanism
In receptor studies, valerenic acid and valerenol bound a specific site on GABA-A receptors (the main inhibitory receptors in the brain, also targeted by benzodiazepines) and enhanced their response to GABA. A point mutation in the β2 or β3 subunit strongly reduced this effect. In mice, valerenic acid reduced anxiety-like behavior, and the effect was absent in mice carrying the β3 mutation (Benke et al., Neuropharmacology 2009).
These are animal and cell findings. The EMA states that the sleep effects seen in trials “cannot be attributed with certainty to any known constituents” (EMA monograph).
How it works in the body
Human pharmacokinetic data are limited to valerenic acid. In 6 healthy adults given a single 600 mg dose of valerian (Anderson et al., Phytother Res 2005):
| Measure | Result |
|---|---|
| Time to peak (5 of 6 subjects) | 1–2 h |
| Peak serum level | 0.9–2.3 ng/mL |
| Elimination half-life | 1.1 ± 0.6 h |
| Measurable in serum | At least 5 h |
| Exposure (AUC) | Highly variable between people; not linked to age or weight |
The authors noted that the 1–2 h peak fits the usual advice to take valerian 30 minutes to 2 hours before bed. The EU monograph states that no pharmacokinetic data are available for the well-established-use extract. It also says the onset of effect is gradual, so valerian is “not suitable for acute interventional treatment,” and that 2–4 weeks of continued use is recommended for an optimal effect (EMA monograph).
Regulatory status
- European Union: the EMA’s herbal committee (HMPC) adopted a monograph in February 2016. A dry ethanol extract has well-established use (supported by published clinical studies) “for the relief of mild nervous tension and sleep disorders.” Other preparations are registered only on the basis of traditional use, meaning long-standing use rather than trial evidence. The proposed ATC code is N05CM09 (hypnotics and sedatives) (EMA monograph; EMA summary).
- United States: herbal products for oral use are usually sold as dietary supplements, which FDA does not approve before sale (NCCIH). Valerian rhizome and roots are listed among natural flavoring substances that may be used in food (21 CFR 172.510). Valerian is not a controlled substance.
- Sport: valerian is not named on the WADA 2026 Prohibited List. As with any supplement, the list says nothing about what a given product actually contains.
What the research shows
Sleep and insomnia: meta-analyses
Reviews of valerian for sleep have reached mixed conclusions. Most find that self-rated sleep quality may improve, while objective measures and validated insomnia outcomes do not.
| Review | Studies | Main finding |
|---|---|---|
| Bent et al., Am J Med 2006 | 16 randomized trials, 1,093 patients | Improved sleep quality (yes/no) in 6 studies: RR 1.8 (95% CI 1.2–2.9), with evidence of publication bias |
| Taibi et al., Sleep Med Rev 2007 | 37 studies (29 controlled) | Most found no difference from placebo; none of the most recent and most rigorous trials found an effect |
| Fernández-San-Martín et al., Sleep Med 2010 | 18 randomized trials | Time to fall asleep: 0.70 min difference (95% CI −3.44 to 4.83); sleep-quality scale: SMD −0.02 (95% CI −0.35 to 0.31); improved sleep quality (yes/no): RR 1.37 (95% CI 1.05–1.78) |
| Leach and Page, Sleep Med Rev 2015 | 14 randomized trials of herbal medicines, 1,602 people with insomnia | No significant difference from placebo for any of 13 efficacy measures; more adverse events per person with valerian than placebo |
| Shinjyo et al., J Evid Based Integr Med 2020 | 10 placebo-controlled trials (sleep quality) | Pooled effect 0.36 (95% CI −0.08 to 0.81), not significant, with high heterogeneity (I² 85%) |
| Valente et al., Eur Neuropsychopharmacol 2024 | Umbrella review of 8 systematic reviews | No evidence of efficacy for insomnia; possible subjective improvement in sleep quality, not shown with objective measures |
In a subgroup analysis, Shinjyo and colleagues found a larger effect in trials of whole root (0.83, 95% CI 0.03–1.62) than in trials of extracts (0.10, 95% CI −0.02 to 0.22). The whole-root estimate rests on few trials, and the authors suggested that variable extract quality may explain the inconsistent results.
Key sleep trials
Large online trial. In Norway, 405 adults aged 18–75 with insomnia were randomized to valerian or placebo for 2 weeks. The valerian dose was three 200 mg extract tablets nightly, equal to 3,600 mg of root (Oxman et al., PLoS One 2007):
| Outcome | Valerian vs placebo |
|---|---|
| Minimally important improvement in sleep quality (primary) | 29% vs 21%; difference 7.5% (95% CI −0.9 to 15.9; p = 0.08), not significant |
| Rated sleep “better or much better” at the end | 5.5% more on valerian (95% CI 0.2–10.8; p = 0.04) |
| Serious adverse events | None in either group |
The authors concluded that valerian appears safe but has “modest beneficial effects at most.”
Sleep-lab trial in older women. In a randomized, double-blind crossover trial, 16 women (mean age 69) with insomnia took 300 mg of concentrated extract or placebo 30 minutes before bed for 2 weeks. There were no significant differences on any measure of time to fall asleep, wake time after sleep onset, sleep efficiency or self-rated sleep quality, measured by polysomnography (overnight sleep recording), actigraphy and diaries (Taibi et al., Sleep Med 2009).
Clinical guideline
The 2017 AASM guideline on drug treatment of chronic insomnia made a weak recommendation: “We suggest that clinicians not use valerian as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults.” The task force cited a lack of efficacy, with the possible exception of small improvements in time to fall asleep, and limited information on harms (Sateia et al., J Clin Sleep Med 2017). For other options reviewed in that guideline, see melatonin. For another herb with a similarly mixed sleep record, see chamomile.
Anxiety
A Cochrane review found only one eligible randomized trial: a 4-week pilot study in 36 people with generalized anxiety disorder comparing valerian, diazepam and placebo. Hamilton Anxiety Rating (HAM-A) scores did not differ significantly between valerian and placebo, and the reviewers concluded the evidence was insufficient to draw any conclusions (Miyasaka et al., Cochrane 2006).
A 2020 meta-analysis of 7 placebo-controlled trials on anxiety found very high heterogeneity (I² 93%) and significant publication bias (Shinjyo et al. 2020). The EMA’s 2025 public summary states that, in the studies it assessed, an ethanol dry extract was as effective as comparator medicines for mild anxiety, but that no comparative long-term studies exist (EMA summary). NCCIH considers the evidence on anxiety, depression and stress insufficient for any conclusion (NCCIH).
Other uses
NCCIH notes that three small studies suggest valerian might help menopausal symptoms, but the evidence is not sufficient. There is not enough evidence on premenstrual syndrome or menstrual cramps (NCCIH). No controlled human trials show effects on muscle growth, hormones, recovery or athletic performance.
Side effects and risks
Overall tolerability
NCCIH describes valerian as generally safe for short-term use by most adults. It has been used with apparent safety at 300–600 mg daily for up to 6 weeks; the safety of long-term use is unknown. Reported side effects include headache, stomach upset, mental dullness, excitability, uneasiness and vivid dreams (NCCIH). The EU monograph lists gastrointestinal symptoms such as nausea and abdominal cramps, with unknown frequency (EMA monograph).
Trial data are mostly reassuring but not uniform. The Norwegian trial found no important differences in minor adverse events versus placebo (Oxman et al. 2007). A 2015 meta-analysis of herbal insomnia treatments found more adverse events per person with valerian than with placebo (Leach and Page 2015).
Drowsiness and driving
The EU monograph warns that valerian may impair the ability to drive or use machines (EMA monograph). NCCIH advises against combining it with alcohol or sedatives, because a sleep-inducing effect is possible though not proven.
Withdrawal
NCCIH reports that some people may have withdrawal symptoms if valerian is stopped abruptly after long-term use. These include anxiety, irritability, heart disturbances, insomnia and, rarely, hallucinations (NCCIH).
Liver
Liver injury has been reported in very rare cases, most often when valerian was taken together with other herbs. Its long-term effect on liver function is unknown (NCCIH). Individual case reports attribute liver injury to valerian (Cohen and Del Toro, J Clin Gastroenterol 2008). Multi-ingredient “sleep” products make it hard to tell which herb is responsible.
Overdose
The EU monograph cites a dose of about 20 g of valerian root that caused fatigue, abdominal cramps, chest tightness, light-headedness, hand tremor and dilated pupils. The symptoms disappeared within 24 hours (EMA monograph).
Interactions
- CYP enzymes: in 12 healthy volunteers, 1,000 mg of valerian nightly for 14 days had no effect on CYP2D6 activity. It slightly raised the peak level of alprazolam, a CYP3A4 probe (25 vs 31 ng/mL), without changing other alprazolam measures. The authors judged clinically significant effects unlikely (Donovan et al., Drug Metab Dispos 2004).
- Broader enzyme panel: 28 days of valerian produced no significant change in CYP1A2, CYP2D6, CYP2E1 or CYP3A4/5 activity in 12 volunteers (Gurley et al., Clin Pharmacol Ther 2005).
- Regulators: the EU monograph lists no reported interactions (EMA monograph). NCCIH advises against use with alcohol or sedatives.
Who should not use it
- Children under 12: not recommended in the EU because of a lack of data on safety and efficacy.
- Pregnancy and breastfeeding: safety has not been established, and use is not recommended in the EU. NCCIH says little is known.
- Allergy: hypersensitivity to valerian is the only listed contraindication for oral use.
Source: EMA monograph; NCCIH.
Quality and product variability
Product content varies widely. An Australian analysis of 31 commercial valerian products (teas, tablets, capsules and liquids) found valerenic acid and its derivatives ranging from under 0.01 to 6.32 mg/g. Products standardized to valerenic acid averaged 3.56 mg/g, versus 0.89 mg/g for non-standardized products (Shohet et al., Pharmazie 2001). Valerenic acid levels in the blood also vary widely between people taking the same dose (Anderson et al. 2005). Both factors may help explain why trial results are inconsistent.
Key takeaways
- Mixed evidence for sleep. Some meta-analyses find better self-rated sleep quality, but time to fall asleep and objectively measured sleep generally do not improve versus placebo.
- Guidelines disagree by region. The EU recognizes a specific ethanol extract for mild nervous tension and sleep disorders; the AASM suggests not using valerian for chronic insomnia.
- Not a fast-acting sleep aid. The EU monograph says effects build gradually and recommends 2–4 weeks of use; valerenic acid itself has a half-life of about 1 hour.
- Generally well tolerated short term. Side effects are usually mild (headache, stomach upset, vivid dreams), but long-term safety, rare liver injury and withdrawal after chronic use are unresolved.
- Low interaction risk in studies, but caution with sedatives. Two human studies found little or no CYP effect; combining it with alcohol or sedatives is advised against.
- No performance effects shown. There are no human trials on muscle, hormones or sport performance, and valerian is not on the WADA list.
Sources
- National Center for Complementary and Integrative Health. Valerian: usefulness and safety. Updated May 2025. NCCIH.
- Committee on Herbal Medicinal Products. European Union herbal monograph on Valeriana officinalis L., radix. EMA/HMPC/150848/2015, Corr. Adopted February 2, 2016. EMA.
- Committee on Herbal Medicinal Products. Assessment report summary for the public: valerian root, Valeriana officinalis L., radix. EMA/HMPC/387742/2025. November 19, 2025. EMA.
- Natural flavoring substances and natural substances used in conjunction with flavors. 21 CFR 172.510. eCFR.
- World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2026. WADA 2026 Prohibited List.
- Anderson GD, Elmer GW, Kantor ED, et al. Pharmacokinetics of valerenic acid after administration of valerian in healthy subjects. Phytother Res. 2005;19(9):801–803. PubMed.
- Benke D, Barberis A, Kopp S, et al. GABA A receptors as in vivo substrate for the anxiolytic action of valerenic acid, a major constituent of valerian root extracts. Neuropharmacology. 2009;56(1):174–181. PubMed.
- Bent S, Padula A, Moore D, et al. Valerian for sleep: a systematic review and meta-analysis. Am J Med. 2006;119(12):1005–1012. PubMed.
- Taibi DM, Landis CA, Petry H, Vitiello MV. A systematic review of valerian as a sleep aid: safe but not effective. Sleep Med Rev. 2007;11(3):209–230. PubMed.
- Fernández-San-Martín MI, Masa-Font R, Palacios-Soler L, et al. Effectiveness of Valerian on insomnia: a meta-analysis of randomized placebo-controlled trials. Sleep Med. 2010;11(6):505–511. PubMed.
- Leach MJ, Page AT. Herbal medicine for insomnia: a systematic review and meta-analysis. Sleep Med Rev. 2015;24:1–12. PubMed.
- Shinjyo N, Waddell G, Green J. Valerian root in treating sleep problems and associated disorders-a systematic review and meta-analysis. J Evid Based Integr Med. 2020;25:2515690X20967323. PubMed; PMC.
- Valente V, Machado D, Jorge S, et al. Does valerian work for insomnia? An umbrella review of the evidence. Eur Neuropsychopharmacol. 2024;82:6–28. PubMed.
- Sateia MJ, Buysse DJ, Krystal AD, et al. Clinical practice guideline for the pharmacologic treatment of chronic insomnia in adults: an American Academy of Sleep Medicine clinical practice guideline. J Clin Sleep Med. 2017;13(2):307–349. PubMed; PMC.
- Oxman AD, Flottorp S, Håvelsrud K, et al. A televised, web-based randomised trial of an herbal remedy (valerian) for insomnia. PLoS One. 2007;2(10):e1040. PubMed; PMC.
- Taibi DM, Vitiello MV, Barsness S, et al. A randomized clinical trial of valerian fails to improve self-reported, polysomnographic, and actigraphic sleep in older women with insomnia. Sleep Med. 2009;10(3):319–328. PubMed.
- Miyasaka LS, Atallah AN, Soares BG. Valerian for anxiety disorders. Cochrane Database Syst Rev. 2006;(4):CD004515. PubMed.
- Donovan JL, DeVane CL, Chavin KD, et al. Multiple night-time doses of valerian (Valeriana officinalis) had minimal effects on CYP3A4 activity and no effect on CYP2D6 activity in healthy volunteers. Drug Metab Dispos. 2004;32(12):1333–1336. PubMed.
- Gurley BJ, Gardner SF, Hubbard MA, et al. In vivo effects of goldenseal, kava kava, black cohosh, and valerian on human cytochrome P450 1A2, 2D6, 2E1, and 3A4/5 phenotypes. Clin Pharmacol Ther. 2005;77(5):415–426. PubMed.
- Cohen DL, Del Toro Y. A case of valerian-associated hepatotoxicity. J Clin Gastroenterol. 2008;42(8):961–962. PubMed.
- Shohet D, Wills RB, Stuart DL. Valepotriates and valerenic acids in commercial preparations of valerian available in Australia. Pharmazie. 2001;56(11):860–863. PubMed.