Kava: benefits, dosage, contraindications

Updated on 19 March 2025

Kava kava is a plant from the pepper family, native to Oceania. It originates from the South Pacific Islands from Hawaii to Papua New Guinea. It is a shrub of 1 to 7 meters. The leaves are 25 cm long, and the roots can reach up to 60 cm in length. The rhizomes have been consumed as a traditional drink in the South Pacific for over 1500 years. Kava kava has been used by certain South Pacific cultures both recreationally and during ceremonies, especially when welcoming guests and new chiefs. The 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 represent 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

Rating methodology

EFSA approval.

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

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

One or more randomized studies or multiple cohorts or epidemiological studies with positive outcomes for the indication.

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

Lack of 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 a placebo in relieving non-psychotic anxiety, comparable to 10 mg buspirone or 30 mg oxazepam. The effects appear dose-dependent: more than 200 mg of kavalactones per day for at least 5 weeks are necessary for optimal benefit. However, kava is ineffective for subclinical anxiety or sporadic 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 involved in anxiety regulation. Specifically, the sedative effects may result from an increase in the number of GABA binding sites in the brain. This mechanism would favor inhibitory neuronal activity, thereby contributing to a sensation of calm. In individuals with generalized anxiety disorder, taking kava is associated with a decrease in 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 coding for a subunit of the GABA-A-rho receptor and another gene involved in catecholamine metabolism. These changes could modulate the balance of neurotransmitters, enhancing 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

Safety 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, increasing the risk of excessive drowsiness and impaired motor reflexes.

Contraindications

Pregnant women: prohibited

The pyrone constituents may reduce uterine tone.

Breastfeeding women: prohibited

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

Liver disorders: prohibited

Kava can worsen liver diseases, even in the short term. Patients with active hepatitis or liver disorders should avoid consumption.

Conseil scientifique