Valerian (Valerian Root)

What valerian is

Valerian is obtained from the root of common valerian, Valeriana officinalis. It is sold as tea, juice, tincture and as a dry extract in tablets and coated tablets, mostly as an approved or registered herbal medicine. In 2016, the EMA’s herbal medicines committee (HMPC) adopted an EU monograph: ethanolic dry extracts are considered “well-established use”, that is, supported by studies, for mild nervous tension and sleep disorders; tea, juice and tinctures are considered traditional use.

What is rated is the state of knowledge. There are many randomized studies, but with very different preparations, doses and measurement methods. Related topics are lavender oil, melatonin, glycine and L-theanine; the basics are covered under Sleep & sleep hygiene.

How it is supposed to work

The most important active compounds are considered to be valerenic acid and valerenol. In the laboratory, both bind to GABA-A receptors, the receptors of the main inhibitory messenger in the brain, and enhance the effect of GABA there. In mice, valerenic acid had an anxiety-relieving effect, but no longer in mice with an altered beta3 subunit of the receptor.

This pathway has not been measured in humans. Which of the many constituents act in humans is open. According to the HMPC, the effect builds up over two to four weeks; valerian is thus more of a course of treatment than a tablet for a single bad night.

What the studies show

Bent 2006: the first large meta-analysis

The paper found 16 placebo-controlled studies with 1,093 patients. Most had clear methodological flaws; doses, preparations and duration differed widely. Six studies reported whether sleep had improved or not; pooled, this was the case 1.8 times as often on valerian as on placebo (95 percent confidence interval 1.2 to 2.9), though with indications of publication bias. The authors’ conclusion: valerian might improve sleep quality without side effects.

Fernández-San-Martín 2010: subjectively yes, objectively no

The meta-analysis of 18 randomized studies separated the types of measurement. More participants on valerian said yes when asked whether their sleep had improved (relative risk 1.37). Time to fall asleep, however, differed by only 0.70 minutes, and sleep quality measured on scales did not differ at all. The authors see a subjective improvement, but no evidence from quantitative or objective measurements.

Oxman 2007: the largest single study

Through a Norwegian television program, 405 people with sleep disorders were recruited who took valerian or placebo for two weeks. A noticeable improvement in sleep quality was achieved by 29 versus 21 percent; the difference narrowly missed statistical significance (p = 0.08), so the primary endpoint was not met. In the overall assessment at the end, 5.5 percent more on valerian found their sleep better (p = 0.04). Side effects did not differ.

Shinjyo 2020: why the results vary

The most comprehensive review to date covered 60 studies with 6,894 participants and meta-analyses on sleep quality (10 studies) and on anxiety (8 studies). The authors attribute the contradictory results mainly to the fluctuating quality of the extracts; they expect more reliable effects from the whole root. They found no serious side effects.

Where the data stop

• Objective measurements. Neither time to fall asleep nor sleep quality measured on scales differed from placebo in the meta-analysis. So far the benefit shows up only in the question of whether sleep feels improved.
• One valerian is not like another. Preparations differ considerably in extraction solvent, extract ratio and content. Results of a study apply only to the extract tested there.
• The guidelines. The American Academy of Sleep Medicine advises against valerian for insomnia with a weak recommendation; the European insomnia guideline 2023 does not recommend herbal medicines overall.
• Long-term use. According to the HMPC, there are no comparative long-term studies.

Status, approval and legal

Valerian root is recognized in the EU as a herbal medicine. The HMPC’s 2016 EU monograph distinguishes two levels: ethanolic dry extracts (extraction solvent ethanol 40 to 70 percent) have “well-established use” status for the relief of mild nervous tension and of sleep disorders; tea, juice, aqueous and methanolic extracts as well as tinctures are considered traditional medicines for the relief of mild symptoms of stress and as a sleep aid. The individual preparations are approved or registered by the national authorities, in Germany by the BfArM. In 2025 the HMPC initiated a routine review of the monograph.

For approved medicines with ethanolic dry extract, the monograph specifies 400 to 600 mg of dry extract as a single dose, for sleep disorders half an hour to one hour before going to bed, at most four single doses per day. The package leaflet of the respective preparation is what counts. Valerian is not recommended for children under 12.

Safety

No serious side effects were noted in the studies or in the HMPC assessment. Nausea and abdominal cramps are possible; their frequency is unknown. Interactions with other medicines had not been described at the time of the assessment.

The HMPC advises against driving or operating machinery after taking it, because valerian can affect the ability to drive. During pregnancy and breastfeeding it is not recommended for lack of data. If symptoms persist or get worse after two weeks of continuous use, this should be checked by a physician or a pharmacist; persistent insomnia can have causes of its own.

Sources

• EMA/HMPC – Valerianae radix (valerian root), EU monograph 2016 and summary
• Bent S et al., Am J Med 2006 – valerian for sleep disorders, meta-analysis of 16 studies
• Fernández-San-Martín MI et al., Sleep Med 2010 – valerian for insomnia, meta-analysis of 18 studies
• Shinjyo N et al., J Evid Based Integr Med 2020 – valerian root for sleep problems, review of 60 studies
• Oxman AD et al., PLoS One 2007 – valerian for insomnia, RCT with 405 participants
• Benke D et al., Neuropharmacology 2009 – valerenic acid and GABA-A receptors
• Sateia MJ et al., J Clin Sleep Med 2017 – American Academy of Sleep Medicine guideline on pharmacological treatment of insomnia
• Riemann D et al., J Sleep Res 2023 – European insomnia guideline 2023