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evidence · mechanism · dose
Supplements/Herb

Kava

aka Piper methysticum

Polynesian anxiolytic with strong evidence; rare hepatotoxicity risk.

Mood & Anxiety

Overview

Polynesian anxiolytic with strong evidence; rare hepatotoxicity risk.

Natural sources
  • Piper methysticum root
Common forms
  • Aqueous extract (safer)
  • WS 1490 (acetonic)

Forms & variants of Kava

Different chemical forms of Kava behave differently. Browse each form's mechanism, bioavailability, and best-use context.

WS-1490 standardized
Kava (WS-1490)

Standardized kavalactone extract for anxiety.

Mechanism of action

Kavalactones modulate GABA-A and inhibit MAO-B.

Pathways
  • · GABA-A modulation

Effects on the body

Decreases
Anxiety

Organ system effects

Brain & CNS

Comparable to buspirone/diazepam for GAD.

Evidence-based benefits

Significant reduction in GAD symptoms

Strong evidence

Potential side effects

Common
  • · Drowsiness
Rare
  • · Dermopathy with chronic use
Serious
  • · Hepatotoxicity (rare, mostly with non-aqueous extracts)

Drug interactions

Benzos / alcohol
Additive sedation; hepatic risk.
severe
Hepatotoxic drugs
Avoid.
severe

Safety & non-supplemental interactions

Educational summary — always confirm with your clinician or pharmacist before starting, stopping, or combining with prescription therapy.

Avoid if you are
  • ·Pregnant or breastfeeding (insufficient safety data)
  • ·Children under 18 (unless directed by a clinician)
  • ·Pregnant or breastfeeding
  • ·Children
Avoid with these conditions
  • ·Liver disease, hepatitis, heavy alcohol use
  • ·Parkinson's disease (worsens symptoms)
  • ·Depression
Avoid / monitor with these medications
  • ·Alcohol
  • ·Benzodiazepines, barbiturates, opioids (additive CNS depression)
  • ·Hepatotoxic drugs (acetaminophen, statins, methotrexate)
  • ·Levodopa
Before surgery
  • ·Stop ≥24 hours before anesthesia — potentiates sedatives.

Supplement interactions

Pairs well with

None listed.

Avoid combining with
  • Alcohol
    Severe additive hepatotoxicity and sedation.
  • Pre-existing liver disease
    Hepatotoxicity risk.

Dosing & bioavailability

Typical dose
60–250 mg kavalactones/d short-term

Where to buy

Affiliate-style search links to reputable retailers. We don't endorse specific brands — verify third-party testing (USP, NSF, Informed Sport) before purchase.

Herb
Kava
Amazon
Wide selection · fast shipping
Herb
Kava
iHerb
Global delivery · curated brands
Herb
Kava
Thorne
Practitioner-grade · NSF tested

Scientific evidence (8)

Systematic reviewExamine.com Supplement Database · 2023

Kava: pharmacology, clinical evidence, and safety — narrative review

Examine.com Research Team

Curated narrative review of human and preclinical evidence for Kava, including mechanism, typical dosing, and safety considerations.

Key findings

Best-supported outcome: Significant reduction in GAD symptoms (evidence: strong). Additional outcomes and limitations summarized in the full profile.

Open study
Systematic reviewPubMed (NLM) · 1970

PubMed: Kava — Significant reduction in GAD symptoms

Live PubMed search

Live results for "Kava Significant reduction in GAD symptoms" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Kava and "Significant reduction in GAD symptoms". Filter by RCT, meta-analysis, or year on the results page.

Open study
Systematic reviewPubMed (NLM) · 1970

PubMed: Kava — randomized controlled trial

Live PubMed search

Live results for "Kava randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Kava and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

Open study
Systematic reviewPubMed (NLM) · 1970

PubMed: Kava — meta-analysis

Live PubMed search

Live results for "Kava meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Kava and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

Open study
Systematic reviewPubMed (NLM) · 1970

PubMed: Kava — pharmacokinetics

Live PubMed search

Live results for "Kava pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Kava and "pharmacokinetics". Filter by RCT, meta-analysis, or year on the results page.

Open study
Systematic reviewPubMed (NLM) · 1970

PubMed: Kava — safety adverse events

Live PubMed search

Live results for "Kava safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Kava and "safety adverse events". Filter by RCT, meta-analysis, or year on the results page.

Open study
Systematic reviewPubMed (NLM) · 1970

PubMed: Kava — dose response

Live PubMed search

Live results for "Kava dose response" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Kava and "dose response". Filter by RCT, meta-analysis, or year on the results page.

Open study
Systematic reviewGoogle Scholar · 1970

Google Scholar: Kava — clinical evidence

Live Scholar search

Cross-database citation index for Kava as it relates to "clinical evidence".

Key findings

Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

Open study
Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.