Quick answer

Valerian root is an herb used for sleep since ancient Greece. In trials of 300 to 900 mg of extract at night, more people said they slept better than on a placebo, but sleep measured in a lab did not change, so the evidence is early. Short-term use appears safe for most adults.^1,2,3,4

Key facts

NIH's supplement fact sheets call the sleep evidence inconclusive and inconsistent.^1,4
NCCIH says valerian has been used with apparent safety at 300 to 600 mg a day for up to 6 weeks.⁴
No single compound explains its effects; valerenic acid and the valepotriates are the main candidates.¹
Rare cases of liver injury have been reported, most often with products that combined valerian with other herbs.^4,5
Valerian should not be taken along with alcohol or sedatives.⁴

What valerian is

Valerian (Valeriana officinalis) is a perennial plant native to Europe and Asia that also grows in North America. Its root has a distinctive odor that many people find unpleasant.^1,4

The valerian genus has more than 250 species, but Valeriana officinalis is the one most used in the United States and Europe.¹

Valerian has been used as a medicinal herb since ancient Greece and Rome. In England during World War II it was used to relieve the stress of air raids.¹

In the United States it is sold as a dietary supplement, either on its own or mixed with other herbs. Studies of mixtures cannot show what valerian does by itself, so this page relies on studies of valerian alone where it can.¹

What the evidence shows

Each claim below carries a grade. Both are graded early, which means the research is too thin or too mixed to rely on. The amount the studies used is shown with each one.

May modestly improve self-rated sleep quality; not shown on objective sleep measures*^1,2,3,6,7

Early evidence

Two meta-analyses found that people taking valerian were more likely than people taking a placebo to say their sleep had improved: about 1.8 times as likely across 6 studies, with signs that negative studies went unpublished, and about 1.4 times across 18 trials. Time to fall asleep, sleep quality scores and sleep measured in a lab did not differ, most trials had flaws, many enrolled adults with diagnosed sleep problems, and NIH calls the evidence inconclusive.

Amount studied: 300 to 900 mg of root extract in the evening, from single nights up to 4 weeks

May ease the severity and frequency of hot flashes around menopause*^4,8,9

Early evidence

Two small placebo-controlled trials in Iran found less severe and less frequent hot flashes after 8 weeks: one in 68 women aged 45 to 55 taking capsules of ground root three times a day (225 or 255 mg each; the paper gives both figures), and one in 60 postmenopausal women aged 45 to 55 taking 530 mg twice a day. NCCIH says small studies suggest valerian might be helpful around menopause, but there is not enough evidence to know for certain.

Amount studied: About 675 to 1,060 mg a day, split into two or three doses, for 8 weeks

NCCIH says relatively little research has looked at valerian, and there is not enough evidence to say whether it is useful for any health condition.⁴

The sleep trials disagree partly because they were so different. They used different amounts, different extracts and different ways of measuring sleep, and many were small or lost a lot of participants along the way. A 2020 review found more consistent results with the dried whole root than with extracts.^1,3

How it might work

In laboratory studies, valerian extract made nerve endings release GABA, a calming chemical messenger, and blocked its uptake, and valerenic acid slowed an enzyme that breaks GABA down.¹

Valerian extracts contain GABA, but whether it crosses from the blood into the brain is not known.¹

The valepotriates are hard to study because they are unstable and break down in storage or in water. Valerian extracts with very little valerenic acid also have sedative effects in animals, so several compounds probably act together.¹

Root, tea, tincture or extract

Supplements are made from the root, rhizomes (underground stems) and stolons (horizontal stems). Dried root is made into teas and tinctures, and dried plant material and extracts go into capsules and tablets.¹

Extracts are sometimes standardized to their content of valerenic acids or valepotriates, but many other compounds are present, and their levels vary widely with the plant and when it was harvested.¹

Water-based extracts contain glutamine, which the body may turn into GABA, while alcohol-based extracts do not.¹

In the United States valerian is sold as a dietary supplement. Because supplements are not always checked for manufacturing consistency, NIH says their composition may vary considerably between production lots.¹

How much people take

The sleep trials NIH describes used 400 to 900 mg of valerian extract at night: 400 or 450 mg of a water-based extract on single nights, or 600 mg of a dried root extract nightly for 2 to 4 weeks.¹

The dosage guide lists the amount used in each trial and how long it ran, and the timing guide covers when to take it.

What's in ours

What’s in ours

Sleep: Valerian Extract, 150 mg per serving, from the label

Our Sleep formula lists 150 mg of valerian extract per serving. That is below the 300 to 900 mg used in the sleep trials, so the grades above do not apply to it at that amount. The label gives no extract ratio.^1,3

Side effects, medicines and who should ask first

Side effects of valerian include headache, stomach upset, mental dullness, excitability, uneasiness and vivid dreams.⁴

In clinical trials, headaches, dizziness, itching and stomach upset were the most common effects reported, but people taking placebo reported similar effects.¹

In very rare cases, liver injury has been reported in people taking valerian, most often in combination with other herbs. NIH's LiverTox database links valerian to rare instances of liver injury, and its long-term effect on the liver is unknown.^4,5

No upper limit has been set for valerian. NCCIH says it has been used with apparent safety at 300 to 600 mg a day for up to 6 weeks, and the safety of long-term use is unknown.⁴

Ask your pharmacist or doctor first

NIH's Office of Dietary Supplements says valerian might add to the effects of sedatives and other medicines that slow the nervous system. It names benzodiazepines such as alprazolam, diazepam, lorazepam and triazolam, and barbiturates and other depressants such as phenobarbital, morphine and propofol. NCCIH says valerian should not be taken along with alcohol or sedatives.^1,4

Expected from how the two work, not shown in studies

NCCIH reports that the American Academy of Sleep Medicine advised against valerian for chronic insomnia in adults in 2017. If poor sleep lasts more than a few weeks, see a doctor rather than relying on a supplement.⁴

Ask first if you are pregnant or breastfeeding: NIH says not to use valerian without medical advice^1,10
Do not give it to a child under 3, and ask a doctor before giving it to any child¹
Ask first if you take melatonin, kava, St. John's wort or another supplement that makes you drowsy¹
Ask first if you have surgery planned: NIH names the anesthetic propofol among the medicines valerian might add to¹
Ask first if you have liver disease⁵
If you have taken it daily for a long time, ask a doctor how to stop, because stopping suddenly can bring withdrawal symptoms⁴

Questions people ask

Why does valerian smell so bad?

Many people find the smell of the dried root unpleasant. It comes from isovaleric acid, which is released as the root's valepotriates break down, so an older or poorly stored product may smell stronger.^1,3

Can I take valerian with melatonin?

NIH's fact sheet lists melatonin, kava and St. John's wort among the supplements that might add to valerian's effects. Our Sleep formula combines 150 mg of valerian extract with 2 mg of melatonin, so ask a pharmacist before adding anything else that makes you drowsy.¹

Is valerian addictive?

The sources here do not describe it that way, but NCCIH reports that some people have withdrawal symptoms, such as anxiety, irritability and trouble sleeping, if they stop suddenly after long-term use. If you have taken it daily for months, ask a doctor how to stop.⁴

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Sources

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.