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Ka6.0
Kava Research
Probably helps
69 peer-reviewed studies
What the evidence says
Too few graded studies
Kava doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality meta-analyses and randomised trials published 2000–2026 with a typical study size of 130 participants.
Based on 69 studies · 10 meta-analyses · 33 RCTs · 5,738 total participants
Confidence
High confidence
What the studies found
1helped1unclear· 67 more without graded effect data
18 studies in the last 5 years · Latest meta-analysis: 2022
200020132026
1Systematic ReviewCited 11×n=1,020 · large study2020
In plain English: Psychotherapy seems indicated for mildly symptomatic adjustment disorder.
Constantin D et al. · American journal of therapeutics (2020)
Systematic review of 23 trials in adults with adjustment disorder: 11 of medicines or plant extracts (kava-kava among them) in 1,020 patients, and 12 of psychotherapy.
Psychotherapy seems indicated for mildly symptomatic adjustment disorder.
For severe symptoms the authors point to benzodiazepines, antidepressants or etifoxine, and the abstract reports no result for kava itself.
2Clinical efficacy measures for insomniaMeta-AnalysisCited 91×n=1,602 · large study2015
In plain English: There was no statistically significant difference between any herbal medicine and placebo, or any herbal medicine and active control, for any of the thirteen measures of clinical efficacy.
Leach MJ et al. · Sleep medicine reviews (2015)
There was no statistically significant difference between any herbal medicine and placebo, or any herbal medicine and active control, for any of the thirteen measures of clinical efficacy.
As for safety, a similar or smaller number of adverse events per person were reported with kava, chamomile and wuling when compared with placebo.
By contrast, a greater number of events per person were reported with valerian.
In plain English: Existing guidelines are generally limited in providing clear, evidence-informed recommendations for the use of CAM therapies for insomnia management due to a lack of high-quality evidence and multidisciplinary consultation in CPG development.
Zhao FY et al. · Frontiers in public health (2023)
The reporting rate of eligible CPGs ranged from 42.9 to 97.1%.
Existing guidelines are generally limited in providing clear, evidence-informed recommendations for the use of CAM therapies for insomnia management due to a lack of high-quality evidence and multidisciplinary consultation in CPG development.
More well-designed studies to provide reliable clinical evidence are therefore urgently needed.
In plain English: There was heterogeneity of study models and methods of investigation across the studies identified.
Celentano A et al. · Journal of oral pathology & medicine : official publication of the International Association of Oral Pathologists and the American Academy of Oral Pathology (2019)
There was heterogeneity of study models and methods of investigation across the studies identified.
Components of kava appear to present an area of interest with chemotherapeutic potential in cancer prevention and treatment, particularly for epithelial neoplasms.
To date, there is a paucity of literature of the utility of kava components in the prevention and treatment of oral squamous cell carcinoma.
In plain English: Medicinal herbs may be promising for the treatment of anxiety.
Zhang W et al. · Pharmacological research (2022)
Noticeable benefit
← WorseNo effectBetter →
Kava was found to be an effective anxiolytic (MD: -2.46, 95% CrI: -4.47 to -0.32) but possibly ineffective in patients with generalized anxiety disorder (MD: -0.17, 95% CrI: -2.55 to -1.97).
Ginkgo biloba (MD: -4.63, 95% CrI: -9.01 to -0.23) and Withania somnifera (MD: -4.90, 95% CrI: -9.70 to -0.17) were efficacious, as measured by HAMA scores but the trials were limited by their small sample sizes.
Conversely, although Passionflower (MD: -4.20, 95% CrI: -8.82 to 0.16) and Saffron (MD: -2.71, 95% CrI: -6.06 to 0.57) did not reduce HAMA scores significantly in the summary network, both were worthy of further study because of support from separate networks.
In plain English: Based on the current data and clinician input, a range of nutraceuticals and phytoceuticals were given either a supportive recommendation or a provisional recommendation across a range of various psychiatric disorders.
Sarris J et al. · The world journal of biological psychiatry : the official journal of the World Federation of Societies of Biological Psychiatry (2022)
Based on the current data and clinician input, a range of nutraceuticals and phytoceuticals were given either a supportive recommendation or a provisional recommendation across a range of various psychiatric disorders.
However several had only a weak endorsement for potential use; for a few it was not possible to reach a clear recommendation direction, largely due to mixed study findings; while some other agents showed no obvious therapeutic benefit and were clearly not recommended for use.
It is the intention of these guidelines to inform psychiatric/medical, and health professional practice globally.
13GAD treatment responseMeta-AnalysisCited 23×n=130 · medium study2018
In plain English: Current evidence, although promising, is insufficient to confirm the effect of Kava for GAD treatment beyond placebo.
Ooi SL et al. · Journal of alternative and complementary medicine (New York, N.Y.) (2018)
Meta-analyses of the results of three placebo-controlled trials (n = 130) favored Kava for GAD treatment with effect sizes between 0.59 and 0.99 (standard mean difference) without reaching statistical significance.
Current evidence, although promising, is insufficient to confirm the effect of Kava for GAD treatment beyond placebo.
New evidence is expected from a large, multisite ongoing trial.
14Motor vehicle crash association and driving performanceSystematic ReviewCited 6×2015
In plain English: With equivocal evidence limited to experimental studies using simulated driving settings, the contribution of kava to MVCs is unknown.
Wainiqolo I et al. · Australian and New Zealand journal of public health (2015)
Systematic review up to August 2014 of kava and motor vehicle crashes, crash injuries or driving performance: no study measured crashes or injuries, and four driving-simulation experiments tested pharmacological doses of kavalactones.
While no statistically significant adverse changes attributable to kava were found, there was weak evidence of slowed reaction time.
One study found visuomotor performance on simulated driving significantly impaired when kava was taken with alcohol.
In plain English: Collectively, the literature reveals preclinical and clinical evidence for various phytomedicines modulating GABA-pathways, with comparative anxiolytic effect to the current array of pharmaceuticals, along with good safety and tolerability profiles.
Savage K et al. · Phytotherapy research : PTR (2018)
An open-ended search to 5 July 2017 was conducted using MEDLINE (PubMed), Scopus, and Cochrane library online databases and performed in a stepped format from preclinical to clinical investigations.
Eligible studies must have had (a) in vitro evidence of GABA-modulating activity, (b) animal studies using anxiety models to test an anxiolytic effect, and (c) human clinical trials.
Ten phytomedicines were identified as having preclinical investigations showing interaction with the GABA system, in addition to human clinical trials: kava, valerian, pennywort, hops, chamomile, Ginkgo biloba, passionflower, ashwagandha, skullcap, and lemon balm.
In plain English: Aside from this, future focus should involve the incorporation of more biomarker analysis, in particular pharmacogenomics, to determine genetic factors moderating response to herbal medicines.
Sarris J · Phytotherapy research : PTR (2018)
Other encouraging herbal medicines with preliminary evidence include Curcuma longa (turmeric) in depression, Withania somnifera (ashwagandha) in affective disorders, and Ginkgo biloba (ginkgo) as an adjunctive treatment in Schizophrenia.
Although depression and anxiety are commonly researched, many other mental disorders still require further prospective investigation.
Although the previous review suggested increasing the adjunctive study of select herbal medicines with pharmaceuticals, this was still only found to sparingly occur in research designs.
In plain English: The majority of evidence suggests that kava has no replicated significant negative effects on cognition.
LaPorte E et al. · Human psychopharmacology (2011)
Systematic review of 10 human clinical trials of kava and cognition, 7 acute and 3 chronic.
One acute study found kava improved visual attention and working memory and another found it increased body sway, while one chronic study found it impaired visual attention under high cognitive demand.
The majority of evidence suggests that kava has no replicated significant negative effects on cognition.
18Anxiety and anxiety-related conditionsSystematic ReviewCited 99×n=2,619 · very large study2010
In plain English: Based on the available evidence, it appears that nutritional and herbal supplementation is an effective method for treating anxiety and anxiety-related conditions without the risk of serious side effects.
Lakhan SE et al. · Nutrition journal (2010)
Of the randomized controlled trials reviewed, 71% (15 out of 21) showed a positive direction of evidence.
Based on the available evidence, it appears that nutritional and herbal supplementation is an effective method for treating anxiety and anxiety-related conditions without the risk of serious side effects.
There is the possibility that any positive effects seen could be due to a placebo effect, which may have a significant psychological impact on participants with mental disorders.
19Hamilton Anxiety Rating Scale scoresMeta-AnalysisCited 24×n=233 · medium study2018
In plain English: Network meta-regression reduced heterogeneity and suggested a modest Kava effect [end-of-treatment Hamilton Anxiety scale score difference adjusted for baseline scores and trial duration: - 3.24 (95% CI - 6.65, 0.17; P = 0.059), Kava Kava 4 arms, n = 139; placebo 5 arms, n = 359].
Barić H et al. · Advances in therapy (2018)
No clear effect
← WorseNo effectBetter →
Borderline
Direct comparisons of Kava Kava (Piper methysticum) extracts to placebo (4 quality trials, n = 233) were highly heterogeneous.
Network meta-regression suggested a modest Kava effect (HAM-A difference -3.24, 95% CI -6.65, 0.17; P = 0.059).
Evidence about efficacy/safety of most CAM methods in GAD is limited; apparent efficacy of certain herbal preparations requires further confirmation.