Valerian is a plant with mild sedative properties that is sold as a sleeping aid and to treat anxiety. But does it work?
In the United States (U.S.), valerian dietary supplements are usually sold as sleeping aids. In Europe, people more often take them for restlessness and anxiety.
There are actually over 250 valerian species, but Valeriana officinalis is the one most commonly used for medicinal purposes.
While medicinal valerian dates back to ancient Greek and Roman times, strong clinical evidence for valerian's effectiveness in treating insomnia and anxiety is lacking.
Still, valerian is considered safe by the U.S. Food and Drugs Administration (FDA) and is gentler than synthetic drugs, such as benzodiazepines and barbiturates. For these reasons, valerian could be worth trying for anxiety or insomnia relief.
Some possible benefits of valerian that have been reported by users include:
- falling asleep faster
- better sleep quality
- relief from restlessness and other anxiety disorder symptoms
- no "hangover effect" in the morning
However, stronger evidence is needed to be confident that valerian, and not some other factor, is responsible for these effects.
It is also necessary to determine whether a person's insomnia and anxiety improvements are statistically significant.
Weaknesses in the studies
While there have been many studies exploring valerian's effects, many of them have weaknesses that make their data unreliable.
Even with carefully controlled studies, it is still difficult to compare and combine data across studies. Some of the reasons for these problems include:
- a small number of study participants
- high rates of study participant withdrawal
- wide variation across studies in methods of measuring sleep quality and anxiety relief
- wide variation across studies in dosage and duration of valerian treatment
- the severity of a person's anxiety or insomnia is not well defined
- flawed statistical analyses
Many of these issues are revealed in a review paper published in the American Journal of Medicine, which carefully analyzed the methods and data of 16 different valerian studies.
The paper produced conflicting results about the soundness of these studies. For example, one issue was that only six of the studies used similar methods to measure sleep quality, which meant that sleep quality improvement could not be compared across all studies.
Combined data shows improvements in sleep
On the other hand, the combined data of these six studies did show a statistically significant improvement in sleep quality for the group of participants using valerian.
These studies also happened to have the largest sample sizes, perhaps giving them more strength than the others.
Still, the authors of this review warn that the results should be taken with caution, as there were many flaws in their statistical analyses.
Studies look at a combination of herbs
A separate issue is that many studies do not explore the use of valerian alone, but instead analyze the effects of valerian combined with other medicinal herbs, such as passionflower or kava.
For example, another literature review analyzed 24 studies about the effectiveness of herbal supplements for anxiety. An individual study explored the impact of herbal supplements on insomnia in 120 participants.
Both found robust evidence for the effectiveness of supplements. However, it was hard to tell how responsible valerian was for these effects.
Larger, more statistically sound valerian-specific studies are needed to understand how well the supplement actually works in terms of treating insomnia and anxiety.
Many researchers believe that it is not just one chemical that is responsible for valerian's effects, but a combination of the plant's components.
According to the National Institutes of Health, several of valerian's chemical compounds have individually demonstrated sedative properties in animal studies.
It is also uncertain how valerian affects the brain. The most common theory is that valerian extract stimulates nerve cells to release a chemical called gamma-aminobutyric acid, or GABA.
GABA slows down nerve cell activity instead of exciting it.
Valerian extract may block an enzyme that destroys GABA, which means that more GABA is available for a longer amount of time.
All of these factors together might produce the calming effect that many who try valerian experience. Drugs such as Xanax and Valium also increase the amount of GABA in the body, and their effects are much greater than valerian.
Valerian dietary supplements are usually made from the plant's roots, but can also derive from its stems. Dried roots, other plant materials, or valerian extracts may be consumed in several forms, including:
The amount of valerian a person should take varies, but the dose typically ranges from 400-900 milligrams (mg) at bedtime.
The dosage may also depend on how much valerenic acid the supplement contains. Valerenic acid is considered to be one valerian's most powerful sedative components.
Herbalists advise only using valerian for 2-3 weeks and then taking a break for an equal length of time before starting up again. Herbalists recommend this break because some people who have used valerian for extended periods have reported adverse side effects, such as headaches, depression, or withdrawal after stopping.
The FDA (or other regulating agencies) do not monitor herbs and supplements for quality or purity. So, it is important to choose products from reliable sources. While further studies are needed to evaluate any potential long-term side effects, there have been very few reports of serious adverse events in connection to valerian.
According to the National Institutes of Health, the side effects most commonly reported by people involved in valerian clinical trials are:
- gastrointestinal disturbances
However, these side effects cannot be directly attributed to valerian, as some of the people who were taking placebo supplements also reported side effects.
Despite valerian's observed gentleness, women who are pregnant or breast-feeding are advised to avoid it because no studies have been carried out on the potential risks of valerian to a fetus or an infant.
Children under 3 years old should not be given valerian either as its effects on early development have not been evaluated.
Finally, a person must consult a doctor before using valerian if they are already taking:
- benzodiazepines, such as Xanax, Valium, or Ativan
- central nervous system depressants, such as phenobarbital or morphine
- other sleep-aiding dietary supplements, such as kava or melatonin
The sedative and depressant properties of these drugs and supplements might combine with those of valerian, resulting in grogginess or more severe adverse effects.
Even if one is not taking any other medications, it is always a good idea to talk to a doctor before taking any supplements, including valerian.
The doctor will provide insight into whether valerian is a good choice, and might also suggest brands and dosages they believe to be most safe and effective.