Valerian — The Sleep Herb That Keeps Failing Its Tests

My starting point

I don't recommend valerian. With poor sleep, I start with what someone does, doesn't do and thinks about in the hours before bed, because that sets up the night far more than anything taken at bedtime. What I see often is a mindset that sleeping pills create: people swap to something that seems healthier, hoping for the same knock-out effect, and when it doesn't come, the worry about not sleeping gets worse. So I came to this expecting valerian to disappoint, and I've tried to give it a fair hearing anyway.

Does it help you sleep?

Low — no reliable effect on how long it takes to fall asleep or on measured sleep; a possible small effect on whether people say they slept better

Valerian has been reviewed so many times that there are now reviews of the reviews. They tell a consistent story.

• Falling asleep, measured in minutes: no difference. A meta-analysis of 18 placebo-controlled trials found valerian shortened the time to fall asleep by 0.7 minutes (95% CI −3.4 to +4.8), which is nothing (Fernández-San-Martín et al., 2010).
• Sleep quality on a rating scale: no difference (standardised difference −0.02, 95% CI −0.35 to 0.31), in the same analysis.
• "Did your sleep improve, yes or no?": here valerian does better. People on valerian were 37% more likely to say yes (relative risk 1.37, 95% CI 1.05 to 1.78) (Fernández-San-Martín et al., 2010). An earlier meta-analysis found a larger effect on the same kind of question, but also found evidence of publication bias: the positive trials were more likely to have been published (Bent et al., 2006).
• The better trials: a systematic review of 37 studies found that most showed no difference from placebo, and "none of the most recent studies, which were also the most methodologically rigorous, found significant effects" (Taibi et al., 2007).
• The latest summary: a 2024 umbrella review of eight systematic reviews concluded there was no evidence that valerian works for insomnia, only for subjective improvement in sleep quality, which hasn't been confirmed by measurement (Valente et al., 2024).

A few of the individual trials make the pattern concrete:

• Measured in a sleep lab: 16 older women with insomnia, two weeks of valerian or placebo, nine nights of recording. No difference on any measure. Time awake during the night actually went up on valerian, though that comparison was against baseline, not placebo (Taibi et al., 2008).
• The largest: 405 people with insomnia in Norway, two weeks. The main outcome, a meaningful improvement in sleep quality, wasn't significantly different (29% on valerian, 21% on placebo). On one overall question, 5.5% more people on valerian rated their sleep better. The authors' conclusion: "modest beneficial effects at most" (Oxman et al., 2007).
• In cancer treatment: 227 people, eight weeks, 450 mg at bedtime. No difference in sleep quality. Some fatigue measures were better, but those were exploratory (Barton et al., 2011).
• Four weeks online: 391 people with anxiety and poor sleep. Valerian did no better than placebo on insomnia (Jacobs et al., 2005).

The placebo point matters here. In that last trial, insomnia scores improved by about 8 points on placebo alone. Poor sleep responds strongly to taking something and paying attention to it. That's why "it worked for me" is weak evidence for any sleep remedy, and why only a placebo-controlled trial can separate the two.

Is it better than elderberry? Similar shape, more data. Both have a popular reputation, some positive early trials, and weaker results as the trials improve. Valerian has far more trials, and so a clearer negative answer.

"The trials used the wrong product"

Plausible, partly supported. It explains the mess; it doesn't rescue the herb

Valerian's defenders have a fair point: the trials used very different things. Root powder, water extracts, alcohol extracts, different doses, some standardised and most not. A 2020 meta-analysis argued this is why results disagree, and that whole root may work more reliably than extracts (Shinjyo et al., 2020). That review is more positive than the others, and its evidence for the "whole root" idea is indirect.

The product problem itself is real. An Australian analysis of 31 retail valerian products found the main marker compounds ranged from below 0.01 to 6.32 mg per gram, a more than 600-fold spread. Products standardised to valerenic acid contained about four times more on average than non-standardised ones, and in the non-standardised products, the amount of valerian listed didn't predict what was actually in them (Shohet et al., 2001). A Canadian study of 14 products also found wide variation, and differences from what the labels claimed (Lefebvre et al., 2004).

So a product can fail because the herb doesn't work, or because there was little herb in it. The trouble is that trials of standardised extracts haven't done much better.

Valerian with hops

Mixed; the positive trials are mostly the manufacturer's own

Many products combine valerian with hops. One fixed combination (Ze 91019) has the most consistent data:

• In a four-week trial, the combination shortened time to fall asleep compared with placebo, while the same dose of valerian alone did not. The lead author worked for the manufacturer (Koetter et al., 2007).
• In a larger 28-day trial in nine US sleep centres, the combination gave "modest" improvements in self-reported sleep, few of them significant against placebo, and no difference on sleep-lab measurements (Morin et al., 2005). The manufacturer's researcher was a co-author.
• A 2025 feasibility study of 40 people found about 22 minutes more sleep a night on Fitbit trackers. That was an exploratory result from a study designed to test whether the trial method worked (Schicktanz et al., 2025).

If you're going to try valerian, the evidence points to this kind of standardised combination rather than valerian alone. It doesn't point strongly.

How it's meant to work

Mechanistic

Compounds in valerian act on GABA receptors in laboratory studies, the same calming system that sleeping pills target (Bruni et al., 2021). That makes it plausible. The human trials are the test of whether plausible becomes useful, and mostly it hasn't.

The European Medicines Agency says valerian works gradually and recommends 2–4 weeks of continued use for full effect (EMA monograph, 2016). Several of the negative trials above lasted four to eight weeks, so "you didn't take it long enough" doesn't explain them away.

Who shouldn't — and the safety picture

Generally safe in trials; rare but real harms

• Side effects in trials are usually mild: stomach upset, headache, grogginess. One meta-analysis of herbal sleep remedies found more adverse events per person on valerian than on placebo (Leach & Page, 2015).
• Liver: the US LiverTox database rates valerian a "probable rare cause" of liver injury (category C). Most cases involved products that combined valerian with other herbs such as skullcap or black cohosh, and most recovered after stopping. Given how widely it's used, LiverTox calls it "a very rare cause" (LiverTox, 2020; case reports: Cohen & Del Toro, 2008; Vassiliadis et al., 2009). If you get dark urine, yellowing skin or eyes, or unexplained itching or tiredness, stop and see your GP.
• Driving: the EMA says valerian "may impair ability to drive and use machines".
• Alcohol, sleeping pills, strong painkillers, sedating antihistamines: don't combine. The concern is the sedative effects adding together, not a proven interaction, but it's the obvious risk (Abebe, 2002).
• Other medicines: two studies in healthy volunteers found valerian had little or no effect on the liver enzymes that clear many drugs (Donovan et al., 2004; Gurley et al., 2005). That's reassuring, though alprazolam peak levels did rise slightly in the first.
• Pregnancy, breastfeeding and under-12s: not recommended; safety hasn't been established (EMA).
• Stopping after long, heavy use: one published case report linked stopping high-dose valerian to delirium and heart complications (Garges et al., 1998). It's a single case, but it's a reason to taper rather than stop abruptly if you've taken a lot for a long time.

What to do instead, or first

Strong

For ongoing insomnia, the recommended first-line treatment is cognitive behavioural therapy for insomnia (CBT-I), not a supplement or a drug (Ell et al., 2023). It's available through the NHS, and some versions are digital. It works better than valerian ever has in a trial. It also targets exactly the cycle I described at the start: the worry about sleep that keeps you awake.

And the Test, Don't Guess question: what's keeping you awake? Valerian doesn't answer that. A sleep diary does more than most tests here: bedtime, wake time, caffeine and its timing, alcohol, screens, and how you feel at 3pm. Two weeks of that often shows the pattern.

If you want to try valerian anyway:

1. Keep a sleep diary for two weeks first.
2. Choose a product standardised to valerenic acid, ideally a valerian–hops combination, and a UK product carrying the THR (Traditional Herbal Registration) mark, which means the MHRA has checked its quality.
3. Take it for four weeks, keep the diary going, and judge it against the diary, not your hopes.
4. No alcohol with it, no driving if it makes you drowsy, and stop if you notice any sign of liver trouble.

The bottom line

• Does it work? Probably not in any measurable way. People sometimes report sleeping better, and placebo explains much of that.
• Is it safe? For most adults, short term, yes. Liver injury is very rare.
• Best bet if you try it: a standardised valerian–hops product with a THR mark, four weeks, with a diary.
• Better bet: CBT-I, and finding out what's keeping you awake.

November's Supplement of the Month is glycine, the next sleep candidate, graded to the same standard.

Sources

PubMed records resolved and abstracts read 30 September 2026.

Abebe W. Herbal medication: potential for adverse interactions with analgesic drugs. J Clin Pharm Ther 2002;27(6):391–401. PMID 12472978. doi:10.1046/j.1365-2710.2002.00444.x

Barton DL, et al. 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). J Support Oncol 2011;9(1):24–31. PMID 21399726. doi:10.1016/j.suponc.2010.12.008

Bent S, et al. Valerian for sleep: a systematic review and meta-analysis. Am J Med 2006. PMID 17145239. doi:10.1016/j.amjmed.2006.02.026

Bruni O, et al. Herbal remedies and their possible effect on the GABAergic system and sleep. Nutrients 2021;13(2):530. PMID 33561990. doi:10.3390/nu13020530

Cohen DL, Del Toro Y. A case of valerian-associated hepatotoxicity. J Clin Gastroenterol 2008;42(8):961–962. PMID 18431248. doi:10.1097/MCG.0b013e3180500348

Donovan JL, 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. PMID 15328251. doi:10.1124/dmd.104.001164

Ell J, et al. Complementary and alternative treatments for insomnia disorder: a systematic umbrella review. J Sleep Res 2023. PMID 37527850. doi:10.1111/jsr.13979

European Medicines Agency, HMPC. European Union herbal monograph on Valeriana officinalis L., radix. Final, 2 February 2016. Accessed 30 Sep 2026.

Fernández-San-Martín MI, et al. Effectiveness of valerian on insomnia: a meta-analysis of randomized placebo-controlled trials. Sleep Med 2010. PMID 20347389. doi:10.1016/j.sleep.2009.12.009

Garges HP, Varia I, Doraiswamy PM. Cardiac complications and delirium associated with valerian root withdrawal. JAMA 1998;280(18):1566–1567. PMID 9820254. doi:10.1001/jama.280.18.1566-a

Gurley BJ, 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. PMID 15900287. doi:10.1016/j.clpt.2005.01.009

Jacobs BP, et al. An internet-based randomized, placebo-controlled trial of kava and valerian for anxiety and insomnia. Medicine (Baltimore) 2005;84(4):197–207. PMID 16010204. doi:10.1097/01.md.0000172299.72364.95

Koetter U, et al. A randomized, double blind, placebo-controlled, prospective clinical study to demonstrate clinical efficacy of a fixed valerian hops extract combination (Ze 91019) in patients suffering from non-organic sleep disorder. Phytother Res 2007;21(9):847–851. PMID 17486686. doi:10.1002/ptr.2167

Leach MJ, Page AT. Herbal medicine for insomnia: a systematic review and meta-analysis. Sleep Med Rev 2015 (online Dec 2014). PMID 25644982. doi:10.1016/j.smrv.2014.12.003

Lefebvre T, et al. In vitro activity of commercial valerian root extracts against human cytochrome P450 3A4. J Pharm Pharm Sci 2004. PMID 15367385.

LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Valerian. NIDDK; updated 5 April 2020. NBK548255. Accessed 30 Sep 2026.

Morin CM, et al. Valerian-hops combination and diphenhydramine for treating insomnia: a randomized placebo-controlled clinical trial. Sleep 2005;28(11):1465–1471. PMID 16335333. doi:10.1093/sleep/28.11.1465

Oxman AD, et al. A televised, web-based randomised trial of an herbal remedy (valerian) for insomnia. PLoS One 2007;2(10):e1040. PMID 17940604. doi:10.1371/journal.pone.0001040

Schicktanz N, et al. Effects of a valerian-hops extract combination (Ze 91019) on sleep duration and daytime cognitive and psychological parameters in occasional insomnia: a randomized controlled feasibility trial. Brain Behav 2025;15(6):e70600. PMID 40462685. doi:10.1002/brb3.70600

Shinjyo N, et al. Valerian root in treating sleep problems and associated disorders — a systematic review and meta-analysis. J Evid Based Integr Med 2020. PMID 33086877. doi:10.1177/2515690X20967323

Shohet D, et al. Valepotriates and valerenic acids in commercial preparations of valerian available in Australia. Pharmazie 2001. PMID 11817170.

Taibi DM, et al. A systematic review of valerian as a sleep aid: safe but not effective. Sleep Med Rev 2007. PMID 17517355. doi:10.1016/j.smrv.2007.03.002

Taibi DM, et al. A randomized clinical trial of valerian fails to improve self-reported, polysomnographic, and actigraphic sleep in older women with insomnia. Sleep Med 2008 (online). PMID 18482867. doi:10.1016/j.sleep.2008.02.001

Valente VG, et al. Does valerian work for insomnia? An umbrella review of the evidence. Eur Neuropsychopharmacol 2024. PMID 38359657. doi:10.1016/j.euroneuro.2024.01.008

Vassiliadis T, et al. Valeriana hepatotoxicity. Sleep Med 2009;10(8):935. PMID 19138557. doi:10.1016/j.sleep.2008.09.009 ---