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.
Valerian root can potentially improve sleep quality and provide relief from anxiety.
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
A combination of studies showed that valerian root may improve sleep quality significantly.
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.