Valerian: a botanical treasure for stress management

Valerian (Valeriana officinalis) is a medicinal plant that has been used for centuries for its sedative and anxiolytic properties. It is one of the most popular natural remedies for promoting sleep and reducing anxiety. This plant, whose roots and rhizomes are mainly used, contains various bioactive compounds such as valepotriates, sesquiterpenes and valerenic acids, which play a key role in its therapeutic effects.

What is Valerian?

Valerian (Valeriana officinalis) is native to Europe and the temperate regions of Asia. Its use as a medicinal plant dates back to antiquity, when it was already recommended by Greek doctors such as Hippocrates and Dioscorides to treat sleep disorders. This perennial plant, recognisable by its silvery-green foliage and white or pink flowers, gives off a distinctive scent that attracts cats, hence its nicknameCatnip. Practitioners harvest valerian root after flowering for therapeutic use, taking advantage of its bioactive compounds, particularly sesquiterpenes and iridoids, which give the plant its sedative effects. Today, experts continue to value valerian for its benefits to the nervous system and its effectiveness in treating sleep disorders andanxiety.

Botanically speaking, valerian (Valeriana officinalis) is a perennial herbaceous plant native to Europe and temperate regions of Asia. It can grow to a height of 1 to 1.5 metres and generally thrives in shady, damp environments. Its leaves are arranged in rosettes at the base and are pinnate, with numerous toothed segments. The sturdy, fluted stem bears small white to pink flowers grouped in umbels. These flowers give rise toachene-shaped fruits topped with feathery bristles.

What are its properties?

Valerian ‘s active ingredients and mode of action are still only partially understood. Although various substances, such asvalerenic acid, valepotriates and glutamine, have been isolated, they appear to be ineffective when administered individually. Researchers now believe that valerian’s effectiveness is based on the combined effect of its compounds, as well as on metabolic products such as baldrinals derived from valepotriates.

The main international health authorities have recognised the efficacy of valerian. TheEuropean Medicines Agency (EMA) validates its use to relieve mild nervous tension and sleep disorders, recommending its use in adults and children over the age of 12. TheWorld Health Organisation (WHO) considers it to be a mild sedative, effective in particular for anxiety-related insomnia. The European Commission andESCOP approve its use to help people fall asleep and relieve nervous tension. The US National Institutes of Health (NIH) confirm its effectiveness for sleep, but stress that the evidence for anxiety remains insufficient.

Action on the GABA system

Gamma-Aminobutyric Acid(GABA) is a key neurotransmitter in the central nervous system, playing a crucial role in neuronal inhibition. It acts primarily via GABA A and GABA B receptors. Binding of GABA to the GABA A receptor leads to an influx of chloride ions (Clˉ) into the post-synaptic neuron, while binding to the GABA B receptor causes an outflow of potassium ions. These mechanisms lead to neuronal hyperpolarisation, thereby reducing the action potential, which explains its role as an inhibitory neurotransmitter.

Benzodiazepines exploit this pathway by facilitating gabaergic transmission, giving these molecules anxiolytic, anticonvulsant, antiepileptic and hypnotic properties. Studies show that valerian also acts on GABA A receptors, increasing the release of GABA into the synaptic cleft and inhibiting its reuptake, mainly viavalerenic acid. This acid, identified as an allosteric modulator, specifically targets certain subunits of GABA A receptors, notably the β2 and β3 subunits, thereby modulating their efficacy. Valerenic acid has a synergistic effect with benzodiazepines, amplifying their action.

Finally, it is important to note that other valerian compounds, such as iridoids, have not shown significant pharmacological activity and degrade rapidly after harvesting.

Effects on the serotonin system

Serotonin, or 5-hydroxytryptamine(5-HT), plays a key role as a central nervous system neurotransmitter, being involved in neurotransmission, digestive tract mobility, psychiatry and the regulation of the sleep-wake cycle. There are several families of serotonin receptors, located in various systems: central nervous system, digestive system, blood vessels and platelets.

Some of these receptor families are important therapeutic targets. For example, triptans, used as antimigraine drugs, are agonists of 5-HT1B/1D receptors, present in the carotid arterial circulation and the central nervous system. Selective serotonin reuptake inhibitors (SSRIs) play an essential role as antidepressants.

Serotonin also contributes to the regulation of circadian rhythm via the 5-HT5A receptor, located in the suprachiasmatic nucleus of the central nervous system.Valerenic acid, a compound in valerian, has been shown to act as a partial agonist of this receptor, which could explain some of valerian’s sedative effects.

Properties on melatonin and glutamate

Melatonin, or N-acetyl-5-methoxytryptamine, is a hormone produced mainly by the pineal gland during the night. It plays an essential role in regulating circadian rhythms, in particular by influencing body temperature. Melatonin MT1 and MT2 receptors are major therapeutic targets, with frequent administration of 2 mg tablets to treat sleep-wake rhythm disorders,primary insomnia in people over 55, and jet lag syndrome. One study showed that a 45% hydromethanolic extract of valerian could interact with ML1 and ML2 melatonin receptors.

Glutamate is the most powerful excitatory neurotransmitter, acting by binding to specific receptors such as ionotropes and metabotropes. Glutamate is also a precursor of the inhibitory neurotransmitter GABA. Some studies suggest that metabotropic glutamate receptors may be inhibited by valerian, reinforcing its sedative effect by reducing glutamate-induced neuronal excitation.

Anxiolytic use

Anxiety is a normal defence response by the body to stress, mobilising its physiological and psychological resources to adapt. Anxiety is generally transient, but can become chronic. Generalised anxiety disorder (GAD) is characterised by a permanent feeling of stress and panic. In France, GAD affects around 5 to 10% of the population, with a higher prevalence among women, in a ratio of 2:1.

Generalised anxiety disorder( GAD ) frequently causes difficulty in falling asleep and muscle stiffness. Biochemically, anxiety imbalances certain neurotransmitters, reducing GABA production and increasing serotonin transmission.

Conventional treatment of GAD often includes the use of benzodiazepines, GABAergic agonists, to restore this balance. The simultaneous use of valerian can potentiate this effect by activating the GABA pathway and increasing its synthesis, offering a complementary approach to the management of anxiety disorders.

How to use this plant?

Based on the studies conducted, theEMA (European Medicines Agency) recommends the use of ethanolic extract of valerian, which is also the most commonly used. Aqueous extracts or herbal tea preparations have not been shown to be significantly effective. The dosage considered most effective by the EMA is as follows: forethanolic extract (40-70% V/V), a dose equivalent to 2 to 3 grams ofdry extract, taken no more than 4 times a day; for dry extract, 0.3 to 1 gram of root extract, also taken no more than 4 times. The minimum duration of treatment to obtain results is 2 to 4 weeks.

If sleep disorders persist or worsen, consult a doctor (EMA/HMPC/150848/2015). Note that valerian can cause undesirable effects, and adjust the doses according to the preparation. For herbal teas, take 2 to 3 grams of powder per cup, up to three times a day.

What are the precautions for use?

The side effects associated with normal use of valerian are generally rare and not serious. They mainly include nausea, intestinal problems and abdominal cramps. Discontinuation of treatment usually eliminates these symptoms, which then require symptomatic management. However, a dose of more than 20 grams of valerian in a single dose causes worrying toxicity. At this level, symptoms such as fatigue, abdominal cramps, chest tightness, dizziness, tremors and mydriasis may appear, but generally disappear within 24 hours.

Valerian may interact with certain drugs, in particular by potentiating the effects of sedatives such as benzodiazepines. Close monitoring of patients taking these combinations remains essential. In the event of liver disorders or when using potentially hepatotoxic drugs, increased vigilance is necessary, despite the limited data available.

For safety reasons, valerian shouldnot be used by pregnant or breast-feeding women, or by children under the age of 12. Due to its sedative effect, do not drive or operate machinery after taking valerian.