History and Traditional Use

Valerian is a plant that originated from Europe and parts of Asia. Valeriana officinalis (European Valerian) is the main species used for medicinal purposes. However, other species also exist which grow in other parts of the world, including V. wallichii (Indian Valerian), V. fauriei (Japanese Valerian), and V. edulis (Mexican valerian). The formation of these species can be explained by the polymorphisms that have occurred as a result of adaptation to different environments.

Valerian has been utilized since the times of the ancient Greeks and Romans. In fact, the Greek physician, Galen, used this herb to treat individuals with epilepsy. Since the 18^th century, valerian was known throughout Europe for its sedative properties. In Ayurvedic medicine, V. officinalis and V. wallichii, were specifically used to treat hysteria, neurosis and epilepsy. During the World Wars, valerian was used to address cases of shell-shock and to help induce sleep. In later years, valerian was introduced in Northeastern America where it was used to alleviate symptoms of insomnia and anxiety disorders. It is considered a nutritional supplement and may come in the form of a capsule, tablet, or liquid extract. Valerian can also be administered in the form of tinctures (alcohol extracts). 

Active Components and Preparation

Active Components

The active ingredients in valerian consist of a mixture of compounds, however most attention has been given to Sesquiterpenoids and Valepotriates. The essential oils of the plant, which is found in the roots, contain a mixture of the active ingredients.

Figure 1. Valerenic acid

Figure 2. Valerenal structure

It has been suggested that valerenal and valerenic acid are the active components that are responsible for the sedative effects of valerian. As shown in the figure below, their structures are based on the valerene ring. However, it must be noted that different species of Valerian contain varying proportions of the active ingredients. For instance, valerenic acid is only found in the European valerian.

Preparation

The valerian root is usually dried then soaked in a solution. Then it is either centrifuged or dried into a powder, which contains the purified active constituents. It can then be encapsulated or made into a tablet. Alternative methods of preparation can be used to make tea. 

Current Use & What does the Science Say?

Today, valerian is used to treat various sleep disorders and anxiety. It is also used as a muscle relaxant and a mild sedative. Valerian is often preferred over pharmaceutical drugs, such as benzodiazepines, because it has fewer side effects. Although valerian has been used for centuries, the scientific evidence supporting its effectiveness remains unclear.

Benzodiazepine

Velerian pills

One study investigated the effectiveness of valerian in treating elderly women with insomnia using a randomized, controlled, double blind, crossover design. Subjects were asked to take a valerian extract (V. officinalis L) or a placebo 30 minutes before bedtime and several sleep quality measures were taken. The results showed no difference between the valerian and the placebo groups in all measures. However, wake after sleep onset (WASO) increased significantly after 2 weeks with the valerian treatment, but not with the placebo. Based on these results, the authors concluded that valerian was not effective in treating elderly women with insomnia.

This study had several positive aspects. First of all, the crossover design allowed subjects to serve as their own control, thus minimizing the biological variation among the subjects. Proper blinding protocols were also applied, and the use of polysomnography provided objective measures of the sleep variables. Nevertheless, there were also some limitations to this study. Since participants were allowed to consume caffeine in the mornings or take naps, this may have confounded the effects of the treatment. In addition, the duration of the study may not have been long enough to observe a significant treatment effect as others have suggested that the effects of valerian on sleep are more long-term. Lastly, the small sample size and the strict inclusion criteria limit the applicability of these results to other sub-populations.

Koetter et al. (2007) examined the efficacy of a valerian/hops extract versus valerian only or a placebo.  A randomized, double blind, controlled, prospective trial was conducted on subjects who suffered from non-organic sleep disorder (defined by sleep latency >30 min). Subjects were randomly allocated into the 3 groups and measurements of sleep efficacy were done through self-reports; sleep latency being the primary outcome. Results revealed that the valerian/hops extract significantly reduced sleep latency compared to the placebo. Although the valerian extract showed improvement in sleep latency from baseline, it was no more efficient than the placebo.

The systematic techniques of this study were one of its positive qualities. Moreover, the negligible adverse side effects of the treatments suppors their safety for use. However, this study also presents a few limitations. For instance, the method for measuring the sleep parameters were not clearly described, making it difficult to determine whether these parameters were subject to methodological bias. Additionally, possible improper use of the home monitor system may have contributed to statistical errors.

As demonstrated by these studies and several others, valerian can be used for sedation or as sleep aids. However, its effectiveness may be dependent on the dose or the species of the plant. Overall, the mixed findings regarding the effects of valerian on sleep disturbances provides insufficient support for its efficacy, but combined formulations may be more effective.

Cautions and Drug Interactions

Adverse Effects

Most clinical trials have claimed no severe side effects with the valerian treatment. However, there are a few side effects for ethanolic valerian extracts, namely gastrointestinal discomfort, headache, drowsiness, irritability, diarrhea, nausea and sweating. For aqueous extracts, nausea and dizziness were the only reported side effects.

It was previously speculated that valepotriates were cytotoxic; however, later studies showed that when orally administered, these compounds were degraded into non-toxic products in the stomach and therefore poses minimal risks to consumers.

Caution

High doses of valerian extracts should be avoided since a dose-dependent increase in side effects has been found in doses greater than 900 mg.

Drug Interactions

 

Commercially available valerian products may be found in combination with other herbal medicines such as hops, St. John's wort, lemon balm and passion flower. In fact, studies have shown that the effectiveness of these products appears to be greater than valerian alone. Furthermore, negligible adverse effects have been reported regarding consumption of these combined herbal medicines.

Sources & Additional Links

Wills RBH, Bone K, Morgan M. Herbal products: active constituents, modes of action and quality control. Nutr Res Rev. 2000;12:47-77.

Houghton PJ. The biological activity of Valerian and related plants. J Ethnopharmacol. 1988;22:121-42.

Taibi DM, Landis CA, Petry H, Vitiello MV. A systematic review of valerian as a sleep aid: Safe but not effective. Sleep Med Rev. 2007;11:209-230.

Steger W. Depressive conditions – comparative random double-blind study of the efficacy of a botanical combination and of a synthetic anti-depressant. Zeitschrift für Allgemeinmedizin. 1985;61:914-918.

Panijel M. Treatment of moderately severe anxiety states. Therapiewoche. 1985;35:4659-4668.

Vorbach EU, Fortelmeyer R, Bruning J. Therapie von Insomnien: Wirksamkeit und Vetraglichkeit eneis Baldrianpraparats. Psychopharmakotherapie. 1996;3:109-15.

Jacobs BP, Bent S, Tice JA, Blackwell T, Cummings SR, An internet-based randomized, placebo-controlled trial of kava and valerian for anxiety and insomnia. Medicine. 2005;84:197-207.

Diaper A, Hindmarch I. A double-blind, placebo-controlled investigation of the effects of two doses of a valerian preparation on the sleep, cognitive and psychomotor function of sleep-disturbed older adults. Phytother Res. 2004;18:831-6.

Ziegler G, Ploch M, Miettinen-Baumann A, Collet W. Efficacy and tolerability of valerian extract LI 156 compared with oxazepam in the treatment of non-organic insomnia: a randomized, double-blind, comparative clinical study. Eur J Med Res 2002;7:480-6.

Schulz H, Stolz C, Müller J. The effect of valerian extract on sleep polygraphy in poor sleepers: A pilot study. Pharmacopsychiatry. 1994;27:147-41.

Useful Links

National Center for Complementary and Alternative Medicine <http://nccam.nih.gov/health/valerian/>