Kava is a plant traditionally used as an intoxicating beverage by the indigenous people of the South Pacific. Kava can also be used to help with anxiety, stress, insomnia, and other disorders. However, high doses of kava may cause liver damage and should not be taken in combination with alcohol or other psychotropic medications. Read on to learn more about the health benefits and side effects of kava.

What is Kava?

Kava (Piper methysticum) extract is traditionally prepared from a combination of kava root and water and is commonly used as a psychotropic beverage in the South Pacific.

Forms of kava product [1]:

  • root extract
  • root capsules
  • tincture
  • root powder
  • root tea
  • concentrate paste

Kava tea, kava root extract, and capsules generally produce mild effects, while tinctures and powders are stronger. Kava paste produces the strongest effects since the product is highly concentrated.

Liver toxicity may be due to the presence of the root and stem peelings in the kava product, instead of only the peeled root [1, 2].

Kaval pyrones and chalcones are the two main active compound classes of kava extract [3, 4]:

  • Kavalpyrones (methysticin, dihydromethysticin, yangonin, dihydrokavain, and kavain) – produce muscular relaxation and calming effect.
  • Chalcones (flavokawain A, B, and C) – combat cancer cell growth, and have antioxidant, anti-inflammatory, and antimicrobial effects.

Mechanisms of Action

  • Kavain and methysticin block sodium ion channels, leading to a decrease in cell excitability. By blocking sodium channels, kavain also reduces excitatory neurotransmitter release. Kavain and methysticin decrease stimulatory pathways, leading to a calming effect [5, 6, 7].
  • Yangonin, kavain, dihydrokavain, methysticin, dihydromethysticin, and kava pyrones increase GABA in the brain (hippocampus, amygdala, and medulla oblongata). When GABA-A receptors are activated, neurons are inhibited, which leads to sedative and anti-anxiety effects [6, 7, 8].
  • Multiple kavalactones (desmethoxyyangonin, methysticin, yangonin, dihydromethysticin, dihydrokavain, and kavain) inhibit monoamine oxidase B. Kavalactones prevent the enzyme MAOB from removing neurotransmitters norepinephrine, serotonin, and dopamine from the brain [6, 7, 9].
  • Kavain, desmethoxyyangonin, and methysticin increase noradrenaline, serotonin, and dopamine. Low levels of noradrenaline, serotonin, and dopamine are associated with depression, anxiety, ADHD, and other disorders [5, 6, 7, 10].

Health Benefits

1) Anti-Cancer

May Stop Breast Cancer Tumor Growth

Cell-based studies showed that kava decreases breast cancer cell size and increases cell death. Flavokawain A, B, and a flavokawain derivative (FLS) in kava increase the concentration of Bax protein, which activates proteins that cause cell death (cytochrome c and caspase 9). Kava also stops the cell cycle and causes cell death by inhibiting the production of the regulatory proteins PLK1 and FOXM1 [11, 12, 13].

A cell-based study showed that kava may prevent breast cancer metastasis. Flavokawain A stops the migration and invasion of cancer cells by inhibiting the formation of blood vessels, which cuts off the nutrient supply to tumors. Flavokawain A also decreases the concentration of GLUT 1, a protein that transports glucose to the tumor for energy [12].

May Stop the Progression of Bladder Cancer

Kava stops the progression of bladder cancer and suppresses tumor growth in mice. Flavokawain A activates pathways (caspase-3/9 and Bax protein) that induce tumor cell death and inhibits proteins that prevent cell death (survivin) in mice [14, 15].

Inhibits Colon Cancer

In cell-based studies, kava (Flavokawain B) inhibited the growth of colon cancer cells (through the release of cytochrome c and Bax/Bak protein) [16, 17].

May Reduce Growth of Prostate Cancer Tumors

Flavokawain B reduces prostate tumor growth, in part by reducing androgen receptors in prostate cells in mice and cell studies. Flavokawain B also kills tumor cells by activating the pathways that cause cell death (caspases and Bax) [18, 19].

2) Treats Anxiety

Multiple human studies showed that kava is effective in the treatment of anxiety, regardless of the symptoms and type of disorder (nonspecific anxiety, tension, agitation, agoraphobia, specific phobia, or general anxiety disorder).

Kava activates GABA-A receptors, which produces a calming effect. Kava prevents a decrease in norepinephrine, serotonin, and dopamine levels by inhibiting monoamine oxidase and relaxes muscles by decreasing beta adrenaline receptor activity [7, 6, 1, 20].

3) Helps Treats Sleep Disorders

Kava helps treats sleep disorders like insomnia. Kava reduced stress and severity of insomnia in 24 patients suffering from stress-induced insomnia. 61 patients suffering from sleep disturbances associated with anxiety, tension, and restlessness were effectively treated with kava extract [21, 22].

Kava’s sedative effects are due to the blocking of sodium and calcium ion channels, increased neurotransmitter binding to GABA-A receptors, inhibition of monoamine oxidase B, and an increase of the neurotransmitters noradrenaline and dopamine [1, 23].

4) Treats Depression

Kava induced a pleasant mental state while reducing fatigue and anxiety in human and animal studies. It can be used as an alternative to antidepressants (benzodiazepines) in the treatment of depression. Kavalactones in kava increase dopamine, serotonin, GABA (only slightly), and decreases glutamate in cell models [24, 25, 26].

5) Protects Against Brain Damage Caused by Parkinson’s and Alzheimer’s Disease

Kavalactones extracted from kava prevent brain damage caused by oxidative stress in brain disorders like Parkinson’s and Alzheimer’s disease in mice and cell studies. Kavalactones activate the Nrf2 antioxidant response pathway and increase the concentration of antioxidant enzymes (heme oxygenase-1), which combat oxidative stress [27, 28, 29].

6) Improves Brain Function

A single dose of kava extract (300 mg) improves accuracy and performance in attention, visual processing, and working memory tasks. Kava pyrones are active in parts of the brain (amygdala, caudate nucleus, and hippocampus) that deal with emotions and brain processes. However, chronic usage and higher doses of kava can result in impaired motor function [1, 30].

7) Aids in the Treatment of Drug Addiction

Kava reduces the cravings for addictive drugs in drug-dependent patients in a pilot study. The anti-craving effects of kava are due to dopamine-producing neurons in the reward system of the brain (nucleus accumbens). The kava pyrone desmethoxyyangonin increases dopamine [31, 32].

8) Reduces the Severity of Epilepsy and Seizures

Kava helps treat seizures and epilepsy in rats. Alone and in combination with the antiepileptic drug diazepam, kava reduces motor activity, increases the seizure threshold, and enhances the anticonvulsant effect of diazepam.

Kava binds to GABA-A receptors in the brain (hippocampus and frontal cortex) and blocks sodium and calcium ion channels in the brain [33].

9) Relieves Symptoms of Menopause

Perimenopause and menopause symptoms include hot flashes, night sweats, insomnia, and increased anxiety and irritability.

Kava treats anxiety, depression, irritability, and insomnia in 80 perimenopausal women (in a DB-RCT) by activating GABA-A receptors, inhibiting monoamine oxidase-B, and increasing dopamine levels in the brain [34, 35, 36].

10) May Reduce Inflammation

In cell-based studies, kavain and flavokawains A and B inhibit NF-kB and decrease TNF-alpha, which play a central role in inflammation [37, 38].

11) May Boost the Immune System

In mice, flavokawains A and B stimulate white blood cells in the spleen, leading to the secretion of cytokines IL-2 and TNF-alpha as well as increasing the level of immune T cells [39].

Side Effects & Precautions

Common side effects of kava consumption include headaches, dizziness, drowsiness, fatigue, depression, mild stomach discomfort, and diarrhea. Heavy and frequent use of kava can cause dry eye and dry scaling skin (dermopathy). These side effects are reversible with reduced intake or cessation [40, 41, 42, 1].

Although kava is generally safe to use, using kava supplements containing stems, leaves, and root peelings can cause liver toxicity and damage. It is recommended to use extracts made from peeled kava rhizomes and roots.

Kava is not recommended as the primary agent for anxiety treatment. Avoid using kava in combination with alcohol to prevent liver damage [1, 7, 43].

Driving and operating heavy machinery is not recommended after consuming kava since kava impairs reaction time and motor skills [1].

Kava can be used recreationally as a psychoactive beverage and has the potential for drug abuse. Drinking kava produces hypnotic, narcotic, and muscle-relaxant effects, which are similar to the effects of alcohol consumption [44].

There have been a few reported cases of kava consumption leading to hepatitis A (a virus transmitted through contaminated water) infection in the liver [45].

Gene and Drug Interactions

Liver toxicity can be caused by an inability to break down kavalactones by cytochrome P450 enzymes CYP3A4 and CYP2D6 [1].

79% of the white population have a CYP2D6 deficiency and break down drugs at a slower rate. Interestingly, only 1% of Asians have CYP2D6 deficiency [1, 46].

Whole kava extract inhibits cytochrome P450 enzymes (CYP1A2, CYP2C9, CYP2D6, CYP3A4, and CYP4A11), which break down many medications [47].

Common drugs that are broken down by CYP450 enzymes include:

  • Diazepam
  • Caffeine
  • Amitriptyline
  • Imipramine
  • Propranolol
  • Fluoxetine
  • Haloperidol
  • Morphine
  • Beta-blockers

Taking these medications in combination with kava could alter the effects of the medication making it necessary to change the dosage [1].



The recommended dose of kava for medicinal use is 6 grams per day in tablet form.

The recommended amount for recreational use is 50 to 200 grams per day as a powdered extract [1].

User Reviews

Kava root extract capsules provide excellent anxiety and stress relief and functions well as a sleep aid. However, some people find that the effects are not strong enough to reduce anxiety and stress. Be cautious though, because Kava can be toxic to some individuals and result in rare, but severe, liver injury.

Kava instant drink mix is a good option for individuals who do not mind the strong taste. The calming effects hit immediately after drinking and last for around an hour.

Some individuals experience a reverse tolerance after consuming kava. Sometimes it might take up to 3 weeks before the full effects kick in.

Buy Kava Supplements

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