Natural Compound

Kava

Piper methysticum

Evidence TierAWADA NOT PROHIBITED

tuneTypical Dose

120-210 MG

watchEffect Window

Acute effect expected in 30-60 minutes. Longer-term outcomes typically emerge by 1-4 weeks.

check_circleCompliance

WADA NOT PROHIBITED

Overview

Clinical Summary

Kava (Piper methysticum) contains kavalactones that influence GABA-related signaling. It is used for anxiety symptom reduction and for sleep improvement secondary to reduced anxious arousal.

Controlled trials support kava for reducing anxiety symptoms, with clinically meaningful effects in some studies. Sleep quality can improve indirectly when anxiety and rumination decrease. Minority findings include reductions in muscle tension and some menopausal symptoms. Rare but serious liver injury reports complicate benefit assessment, so extract type, screening, and quality are central to risk-adjusted benefit.

Kava kavalactones appear to reduce central arousal through GABA-A positive allosteric modulation and related CNS signaling effects, with additional monoamine and ion-channel modulation that supports anxiety and relaxation outcomes.

Outcomes

What This Is Expected To Influence

Primary Outcomes

  • Reduce HAM-A and related anxiety scores, including acute 30-60 minute symptom improvement versus placebo in some trials.

Secondary Outcomes

  • Improve perceived stress and support shorter sleep latency when anxiety-related insomnia is present.
  • Sustained anxiety/stress benefit over 1-4 weeks and continued stability at ~210 mg/day to 24 weeks in selected cohorts.

Safety

Contraindications and Interactions

Contraindications

  • Pregnancy
  • Lactation
  • Active severe liver disease
  • Uncontrolled psychiatric instability
  • Severe cardiac, renal, or endocrine comorbidity unless clinician cleared

Side effects

  • Mild transient drowsiness/sedation
  • Headache
  • Dizziness
  • GI upset
  • Fatigue
  • Restlessness
  • Tremors
  • Kava dermopathy (dry, scaly, yellow-discolored skin with chronic heavy use, generally reversible after discontinuation)
  • Rash (sebotropic reactions, hives, redness, and itching, often reported after short-term use)
  • Intoxication at high doses (sedation, tremors, and cognitive/motor/visual impairment, rare extrapyramidal symptoms)
  • Rare liver-toxicity signals (jaundice, dark urine, abdominal pain, unusual fatigue) requiring immediate discontinuation and medical review

Interactions

  • Drugs that are CYP2E1 (Possible/Moderate) - Kava may inhibit CYP2E1, which could reduce metabolism of CYP2E1 substrate medications. This effect was noted with ethanolic extracts and may vary by preparation.
  • Drugs that are CYP1A2 (Possible/Moderate) - Kava may inhibit CYP1A2, which could reduce metabolism of CYP1A2 substrate medications, though findings are inconsistent.
  • Alcohol (Possible/Moderate) - Combining kava with alcohol may increase sedation, cognitive impairment, and liver-toxicity risk.
  • Benzodiazepines (Possible/Moderate) - Kava may enhance the sedative effects of benzodiazepines.
  • Drugs that cause drowsiness/sedation (Possible/Moderate) - Kava can cause drowsiness.
  • Supplements that are CYP2E1 substrates (Possible/Unknown) - Kava may inhibit CYP2E1 and alter metabolism of CYP2E1 substrate supplements. Effect may depend on extract type.
  • Supplements that are CYP1A2 substrates (Possible/Unknown) - Kava may inhibit CYP1A2 and alter metabolism of CYP1A2 substrate supplements, though findings are inconsistent.
  • Drugs that are CYP2C9 substrates (Theoretical/Unknown) - Kava has been reported to inhibit CYP2C9 in vitro.
  • Hepatotoxic medications (Possible/Moderate) - Concurrent use may increase stacked liver burden and adverse-event risk.

Avoid if

  • Pregnancy considerations
  • Lactation considerations
  • People using alcohol
  • People using benzodiazepines
  • People using drugs that cause drowsiness/sedation
  • People using drugs that are cyp2e1
  • People using drugs that are cyp1a2
  • Active unstable hepatic, psychiatric, renal, or cardiovascular disease
  • Active malignancy
  • Concurrent hepatotoxic medication stacks

Evidence

Study-level References

kava-SRC-001Cochrane human randomized evidence synthesis (meta-analytic)
Sourceopen_in_new

Pittler, M. H., & Ernst, E. Cochrane Review: Kava for anxiety, 2003

Population: Adults

Dose protocol: 120-210 mg kavalactones/day, including acute and maintenance follow-up in selected studies to 24 weeks

Key findings: Kava demonstrated reduction in anxiety scales versus placebo with signal size described as clinically meaningful and in some analyses comparable to benzo-caliber acute symptom change, with effects detectable within 30-60 minutes and sustained benefit reported at 1-4 weeks. Selected continuation data reported tolerability and response stability to ~24 weeks at ~210 mg/day.

Notes: Cochrane synthesis has historical concerns around trial quality and formulation standardization. Monitor product quality in implementation.

Paper content

Kava demonstrated reduction in anxiety scales versus placebo with signal size described as clinically meaningful and in some analyses comparable to benzo-caliber acute symptom change, with effects detectable within 30–60 minutes and sustained benefit reported at 1–4 weeks. Selected continuation data reported tolerability and response stability to ~24 weeks at ~210 mg/day.

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