Introduction

Valerian root is an herbal remedy derived from the root portion of the valerian plant (Valeriana officinalis). It is often used to treat sleep disorders, anxiety, and epilepsy. Its role as a sedative and sleep aid has been known since the 2^nd century AD, earning it a solid place in the arsenal of folk remedies. Although valerian root has traditionally been used to treat sleep disorders, modern research has delved deeper into its relaxation-promoting effects, thereby helping it earn today’s nickname of ‘nature’s valium’.

It's believed that valerian root can help mitigate the body’s stress response by modulating receptors in the brain that are involved in stress and relaxation. Research shows that valerian root extract can modulate gamma-amino butyric acid-A (GABA-A) receptors in the brain. GABA plays a key role in the brain and acts as the primary inhibitory neurotransmitter of the nervous system. Its main function is to rapidly inhibit neuronal excitability via the inhibition of nerve transmission in the brain.

An overview of stress

Physiological stress, better known simply as ‘stress’, refers to a complex physiological process that occurs within the body in response to any stimuli that disrupt the body’s homeostatic state. As such, stress can occur in response to both external (e.g. physical threats) and internal stimuli (e.g. intense emotions).

The stress response can be further categorised into two different responses that each have different origins and outcomes within the body.

Firstly, a fast stress response is mediated by the sympathetic-adreno-medullar (SAM) axis. This involves the rapid secretion of norepinephrine and epinephrine from the adrenal medulla into the bloodstream, as well as an increased secretion of norepinephrine from sympathetic nerves in the body. The symptoms associated with the fast stress response correlate with the symptoms of acute stress and commonly consist of an elevated heart rate, elevated blood pressure, sweating, and nausea.

Secondly, the hypothalamus-pituitary-adrenal (HPA) axis mediates the slow response through the release of corticotropin-releasing hormone (CRH) from the paraventricular nucleus of the hypothalamus into the bloodstream. The release of CRH further stimulates the anterior pituitary gland to release adrenocorticotrophin hormone (ACTH) into the bloodstream which in turn mediates the release of cortisol from the adrenal cortex. Circulating cortisol acts directly on a wide range of organ systems, including the digestive system, endocrine system, and immune system.

Although the stress response is normally transient and adaptive - and therefore not harmful - repetitive or chronic exposure to a stressor can cause chronically elevated levels of stress markers which, over time, can have deleterious effects on the body.

Considering that stress markers act on a wide range of tissues, the effects of chronic stress can potentially be devastating. For this reason, it’s important to recognise the hallmarks of stress in one’s life and to make the necessary changes to manage stress well. Fortunately, natural relaxation-promoting compounds such as valerian root can prove a helpful remedy by promoting sleep and combatting the stress response.

Valerian root mechanism of action

Valerian root (V. officinalis) is a perennial plant belonging to the Valerianaceae family that is native to Europe and Asia. The genus Valerian includes over 200 species and V. officinalis is the most well-known species.

Valerian root extract contains many chemical constituents that affect the body, though no single active constituent has been identified as the agent responsible for its sedative properties. However, valerenic acid is proposed to be one of the main constituents of valerian root and has demonstrated sedative effects in several animal studies.

Studies have proposed the sedative and anxiolytic (anxiety-reducing) properties of valerenic acid to be mediated through the modulation of GABA-A receptor subunits Beta-2 and Beta-3 in mice. Another study has further highlighted Valerenic acid as a positive allosteric modulator of the GABA-A receptor.

GABA is responsible for inducing rapid synaptic inhibition by interacting with the GABA-A receptor. GABA-A receptors are pentameric structures that are constituted of three different types of subunits: alpha, beta, and gamma. These subunits are arranged around a central ion channel that regulates the flux of certain ions in and out of the cell. Both subunit composition and arrangement determine the functional properties of the GABA-A receptor and the affinity of endogenous (made within the body) and exogenous (external) ligands.

Positive modulation of the GABA-A receptor induces a conformational change that permits the influx of chloride ions into the neuronal cell. In turn, this results in hyperpolarisation of the cell and a resultant diminished action potential which prevents the release of excitatory neurotransmitters such as glutamate from the neuron. Common positive modulators of GABA-A include well-known sedatives such as benzodiazepines, barbiturates, and ethanol.

The positive allosteric modulation of the GABA-A receptor by valerenic acid prevents the release of excitatory neurotransmitters in the brain. This could partially explain the sedative and anxiolytic effects of valerian root. In turn, the sedative and sleep-promoting effects of valerian root may indirectly affect the as sleep deprivation is a key driver of stress.

Studies show that CRH-releasing neurons, which govern the HPA axis (and therefore downstream cortisol secretion in the body), are regulated by GABAergic inhibition. This suggests a possible relationship between the influence of positive allosteric modulation of GABA-A receptors in neurons and the modulation of the HPA axis involved in the stress pathway, although the precise mechanism of action and the nature thereof have not been elucidated.

Safety and practical uses of valerian root

Valerian root is generally considered safe and well-tolerated for use on a short-term basis for up to 28 days in otherwise healthy adults and the elderly.

Side effects are unlikely to occur and are mild, but instances of nausea, abdominal pain, and paradoxical effects including agitation and restlessness have been reported in a minority.

Valerian root extract dosages may range from 100-1600 mg and do not seem to impair cognitive or psychomotor performance within this dose range. The most common dosages of valerian root extract range between 300-600 mg and are usually taken between 2 hours to 30 minutes before bedtime.

Although valerian root does not appear to interact with any other medicines, caution is advised when taken in conjunction with medicines that induce drowsiness as well as sleep aids, as valerian extract could accentuate these effects.

FAQs

Is valerian root addictive?

It is well known that sedative and anxiolytic medications can be highly addicting. Like valerian root, the benzodiazepines (e.g. Valium, Xanax) and barbiturates (e.g. Amytal) classes of drugs are positive modulators of the GABA-A receptor and are highly addictive, even with short-term use. Fortunately, valerian root does not appear to cause dependency or withdrawal issues in the majority of people, though there are some reports of withdrawal symptoms in cases where valerian root has been used for an extended period of time.

What are the long-term effects of taking valerian root?

Although valerian root is generally considered to be safe for all ages and does not pose any risk regarding possible drug interactions, the overall safety of valerian root over long periods has not been extensively studied and remains unknown. For this reason, it is not recommended to use valerian root for a period longer than 28 days without the approval of your healthcare provider.

Can valerian root be combined with other stress-reducing herbal remedies?

Since studies have highlighted the overall safety of valerian root and have not reported any significant interactions with other compounds, it may be possible to safely combine valerian root with other stress-reducing compounds.

Valerian root is most commonly combined with other sedative herbal remedies including passion flower, hops, and lemon balm. However, always ensure the approval of your healthcare provider prior to changing or consuming herbal remedies as they could have adverse effects when taken together.

Summary

Valerian root is a well-known traditional herbal remedy and its use in relieving sleep disturbances and restlessness dates back to ancient history. In recent times, valerian root’s usage for stress and insomnia relief has seen a surge, especially since several studies have been able to prove its efficacy. Studies highlight the valerian root’s ability to promote stress relief directly by targetting receptors in the brain, and indirectly by promoting restful sleep.

Valerian root is generally considered safe and is well-tolerated by the majority of people without the onset of side effects. In a small minority of people, mild side effects may occur. Overall, there is sufficient scientific evidence to indicate that valerian root may be an effective herbal remedy in the treatment of stress, mild anxiety, and sleep disturbances in the short term.