Kava
Research reviewed: Up until 03/2026
Kava (Piper methysticum) is a dietary supplement with 10 published peer-reviewed studies involving 860 participants, researched for Anxiety Treatment, Sleep Quality, Menopausal Symptoms and 1 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Anxiety Treatment
StrongSleep Quality
StrongMenopausal Symptoms
StrongSafety & Tolerability
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Anxiety Treatment
To evaluate Kava extract on generalised anxiety disorder
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate Kava extract on generalised anxiety disorder
Dose
300 mg/day WS-1490 Kava extract (70% kavalactones)
Participants
60 patients with anxiety disorders
Duration
24 weeks
Results
Significant and progressive reduction in HAM-A scores vs placebo (p<0.001). Anxiety relief established from week 4. No adverse effects on liver function.
How They Measured It
Hamilton Anxiety Scale (HAM-A), CGI, State-Trait Anxiety Inventory
To compare Kava extract to buspirone and opipramol in generalised anxiety disorder
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To compare Kava extract to buspirone and opipramol in generalised anxiety disorder
Dose
400 mg/day WS-1490 Kava
Participants
129 patients with GAD
Duration
8 weeks
Results
Kava, buspirone, and opipramol all produced significant reductions in HAM-A. Kava response rate (75.3%) comparable to buspirone (72.4%) and opipramol (70.9%). No significant differences.
How They Measured It
HAM-A, CGI, response rate
To assess the efficacy and safety of Kava extract for anxiety
Study Type
Systematic review and meta-analysis
Purpose
To assess the efficacy and safety of Kava extract for anxiety
Dose
60-280 mg kavalactones/day
Participants
Meta-analysis of 11 RCTs (645 patients)
Duration
4-24 weeks
Results
Significant reduction in anxiety vs placebo (SMD -0.58, p<0.001). Well-tolerated at typical doses. Liver safety concerns noted with heavy or long-term use.
How They Measured It
HAM-A, STAI, anxiety scales across 11 RCTs
To evaluate water-based Kava extract on anxiety with reduced hepatotoxicity risk
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate water-based Kava extract on anxiety with reduced hepatotoxicity risk
Dose
250 mg/day aqueous Kava extract
Participants
75 patients with GAD
Duration
6 weeks
Results
Significant reduction in GAD-7 and HAM-A scores (p=0.001). Cortisol levels reduced. Liver function tests remained normal throughout. Aqueous extract appears safer.
How They Measured It
GAD-7, HAM-A, salivary cortisol, liver function
Sleep Quality
To evaluate Kava extract on insomnia and sleep quality in anxious patients
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate Kava extract on insomnia and sleep quality in anxious patients
Dose
200 mg/day WS-1490 at bedtime
Participants
61 adults with insomnia due to anxiety
Duration
4 weeks
Results
Significant improvement in ISI scores (p=0.001) and PSQI. Sleep efficiency increased. PSG showed improved non-REM sleep architecture. Anxiety and sleep dual benefits.
How They Measured It
Insomnia Severity Index, PSQI, polysomnography
To assess acute effects of Kava on EEG and cognitive function during relaxation
Study Type
Randomised, crossover, placebo-controlled
Purpose
To assess acute effects of Kava on EEG and cognitive function during relaxation
Dose
150 mg kavalactones
Participants
20 healthy adults
Duration
Acute crossover
Results
Kava significantly increased alpha wave activity (p<0.05) and subjective relaxation. Cognitive function unimpaired. Relaxation without sedation demonstrated.
How They Measured It
EEG alpha/beta wave ratio, cognitive testing, subjective relaxation
Menopausal Symptoms
To evaluate Kava for anxiety and menopause-related symptoms
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate Kava for anxiety and menopause-related symptoms
Dose
100 mg/day Kava extract (70% kavalactones)
Participants
40 postmenopausal women
Duration
8 weeks
Results
Significant reduction in HAM-A anxiety scores and Kupperman Index (p<0.001). Hot flush frequency reduced. Mood and quality of life improved vs placebo.
How They Measured It
HAM-A, Kupperman Menopausal Index, hot flush frequency
To compare Kava with HRT for anxiety in perimenopausal women
Study Type
Randomised, double-blind, controlled
Purpose
To compare Kava with HRT for anxiety in perimenopausal women
Dose
100-200 mg/day Kava extract
Participants
50 perimenopausal women
Duration
6 months
Results
Kava significantly reduced anxiety (HAM-A) to a comparable degree as HRT. No hormonal effects detected. Kupperman symptom scores improved in both groups equally.
How They Measured It
HAM-A, Kupperman Index, endocrine markers
Safety & Tolerability
To evaluate long-term safety of water-soluble Kava extract on liver function
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate long-term safety of water-soluble Kava extract on liver function
Dose
250 mg/day aqueous Kava extract
Participants
80 patients receiving chronic Kava treatment
Duration
6 months
Results
No significant changes in liver function markers vs placebo. Aqueous (water-based) extraction appears to have significantly lower hepatotoxicity risk than acetonic/ethanolic extracts.
How They Measured It
LFTs (ALT, AST, GGT, bilirubin), renal function
To review evidence for Kava on anxiety and safety profile
Study Type
Systematic review
Purpose
To review evidence for Kava on anxiety and safety profile
Dose
Various
Participants
Systematic review
Duration
Various
Results
Strong evidence for anti-anxiety efficacy. Hepatotoxicity risk real but primarily associated with acetone/ethanol extracts in susceptible populations. Aqueous extracts appear safer. Dose and extraction method critical.
How They Measured It
Systematic review of RCTs and adverse event reports
Frequently Asked Questions
Common questions about Kava research
There are currently 10 peer-reviewed studies on Kava (Piper methysticum), involving 860 total participants. Research covers Anxiety reduction, Sleep quality, Stress relief and 1 more areas. The overall evidence strength is rated as Very Strong.
The evidence is currently rated as "Very Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (10 human studies), and reported outcomes.
Kava has been researched for: Anxiety reduction, Sleep quality, Stress relief, Mood enhancement. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 10 out of 10 studies are human trials. Human trials carry more weight in our evidence scoring system.
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