Kava: benefits, dosage, contraindications

Mis à jour le 7 November 2025

Kava kava is a plant in the Piperaceae family native to Oceania. It is native to the South Pacific islands, from Hawaii to Papua New Guinea. It is a shrub that grows 1 to 7 meters tall. The leaves are about 25 cm long, and the roots can reach up to 60 cm in length. The rhizomes have been consumed as a traditional beverage in the South Pacific for more than 1,500 years. Kava kava has been used by some South Pacific cultures recreationally and during ceremonies, notably when welcoming guests and new chiefs. Dietary supplements are made from the dried rhizome, generally without roots. The characteristic constituents of kava kava are pyrones, known as kavalactones. The six most common kavalactones are desmethoxyyangonin, 7,8-dihydrokavain, yangonin, kavain, 7,8-dihydromethysticin and methysticin. In the dried plant, these kavalactones make up at least 3.5% of the composition. It is used in traditional medicine for relaxation. It is also used for the short-term symptomatic treatment of moderate anxiety and insomnia due to nervousness and stress.

Other name(s)

Kava Kava

Scientific name(s)

Piperis methystici rhizoma

Family or group:

Plants

Indications

Scoring methodology

EFSA approval.

Several randomized, double-blind, controlled clinical trials (> 2), including a significant number of patients (>100), with consistently positive conclusions for the indication.

Several randomized, double-blind, controlled clinical trials (> 2), including a significant number of patients (>100), with positive conclusions for the indication.

One or more randomized studies, or several cohorts or epidemiological studies, with positive conclusions for the indication.

Clinical studies exist but are uncontrolled, with conclusions that may be positive or conflicting.

No clinical studies to date that can demonstrate the indication.

Anxiety
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Meta-analyses and clinical trials show that standardized kava extracts (150-400 mg/day, containing 70% kavalactones) are more effective than placebo for relieving non-psychotic anxiety, comparable to 10 mg of buspirone or 30 mg of oxazepam. The effects appear dose-dependent: more than 200 mg of kavalactones per day for at least 5 weeks are necessary for optimal benefit. By contrast, kava is ineffective for subclinical anxiety or for occasional use.

Posologie

Oral: rhizome

150 - 400 mg

standardized extract

The effectiveness and safety of Kava Kava for treating anxiety symptoms: A systematic review and analysis of randomized clinical trials
Medicinal herbs for the treatment of anxiety: A systematic review and network meta-analysis
Clinician guidelines for the treatment of psychiatric disorders with nutraceuticals and phytoceuticals: The World Federation of Societies of Biological Psychiatry (WFSBP) and Canadian Network for Mood and Anxiety Treatments (CANMAT) Taskforce

Properties

Anxiolytic

Kava is well known for its anxiolytic and sedative effects, mainly attributed to its active compounds, the kavalactones. Although the exact mechanisms of these effects are not completely elucidated, laboratory studies suggest that kava acts by modulating the GABA system, a key neurotransmitter in the regulation of anxiety. More specifically, the sedative effects may result from an increase in the number of GABA binding sites in the brain. This mechanism would promote inhibitory neuronal activity, thereby contributing to a feeling of calm. In people with generalized anxiety disorder, kava use is associated with decreased GABA levels in the dorsal anterior cingulate cortex, a region involved in emotion regulation. Furthermore, kava influences gene expression by reducing the activity of a gene encoding a subunit of the GABA-A-rho receptor and of another gene involved in catecholamine metabolism. These changes could modulate the balance of neurotransmitters, reinforcing the anxiolytic effects.

Usages associés

Anxiety

Effect of kava (Piper methysticum) on peripheral gene expression among individuals with generalized anxiety disorder: A post hoc analysis of a randomized controlled trial
Neuroimaging Insights: Kava's (Piper methysticum) Effect on Dorsal Anterior Cingulate Cortex GABA in Generalized Anxiety Disorder

Safe dosage

Adult: 150 mg - 400 mg (standardized extract)

For adults, kava extracts are generally used at a dose of 150 to 400 mg per day, standardized to 70% kavalactones, for a duration of up to 6 months under medical supervision.

Interactions

Médicaments

Central nervous system depressants: strong interaction

Kava should not be combined with central nervous system depressants such as alcohol or benzodiazepines. This combination can lead to additive sedative effects and increase the risk of excessive drowsiness and impaired motor reflexes.

Contraindications

Pregnant women: contraindicated

Pyrone constituents may reduce uterine tone.

Breastfeeding women: contraindicated

Pyrone constituents may pass into breast milk, posing a risk to the infant.

Liver disorders: contraindicated

Kava can worsen liver disease, even in the short term. Patients with active hepatitis or liver disorders should avoid consuming it.

Conseil scientifique