Evidence Based
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6 Health Benefits of Kava + Side Effects

Written by Carlos Tello, PhD (Molecular Biology) | Last updated:
Evguenia Alechine
Jonathan Ritter
Puya Yazdi

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Kava
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 the plant should not be taken in combination with alcohol or other psychotropic medications. Read on to learn more about the potential 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 products include [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.

Importantly, several cases of liver damage and even death from taking kava (possibly due to the presence of the root and stem peelings in the kava product, instead of only the peeled root) have been reported. For this reason and its potential for abuse, kava is banned in Europe, the UK, and Canada [1, 2].

Kavalpyrones 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) have potential antioxidant, anti-inflammatory, antimicrobial, and anticancer 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, possibly 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 may have 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].

Snapshot

Proponents

  • May reduce anxiety
  • May improve sleep disorders and depression
  • May improve mood symptoms associated with menopause

Skeptics

  • Insufficient evidence for many benefits
  • Several cases of liver damage and even death reported
  • High potential for abuse
  • Banned in several countries
  • High risk of drug interactions

Health Benefits

Likely Effective for:

Anxiety

Multiple human studies showed that kava improved anxiety, regardless of the symptoms and type of disorder (nonspecific anxiety, tension, agitation, agoraphobia, specific phobia, or general anxiety disorder) [11, 12, 13, 14, 15, 16, 17, 18].

In a clinical trial on 129 people with generalized anxiety disorder, kava extract (400 mg) was as effective as two anti-anxiety drugs (opipramol 10 mg and buspirone 100 mg) [12].

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, 18].

All in all, the evidence suggests that kava may help with anxiety. Remember that this supplement is not approved by the FDA for this purpose and is even banned in some countries due to its potential for abuse and risk of liver damage. Discuss with your doctor if it may be helpful in your case and always take it as recommended by them.

Insufficient Evidence for:

1) Sleep Disorders

Kava reduced stress and improved sleep quality in 24 patients suffering from stress-induced insomnia. 61 patients suffering from sleep disturbances associated with anxiety, tension, and restlessness were also effectively treated with kava extract [19, 20].

Kava’s potentially 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, 21].

Although promising, the evidence to support the use of kava in sleep disorders is insufficient. More clinical trials on larger populations are needed to confirm these preliminary results.

2) Depression

In a clinical trial on 60 people with generalized anxiety disorder, oral kava extract (250 mg kavalactones per day) reduced both anxiety and depressive symptoms [2].

Its combination with Saint John’s wort improved depression (but not anxiety or quality of life) in a small trial on 28 people with major depressive disorder [2].

Kava induced a pleasant mental state while reducing fatigue and anxiety in human and animal studies. Kavalactones in kava increased dopamine, serotonin, GABA (only slightly), and decreased glutamate in cell models [22, 23, 24].

Again, the results are promising but only two small clinical trials have been conducted. Further clinical research is required to confirm the potential benefits of kava in people with depression.

3) Menopausal Symptoms

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

Kava improved anxiety, depression, irritability, and insomnia in 3 clinical trials on 120 perimenopausal and menopausal women. It activated GABA-A receptors, inhibited monoamine oxidase-B, and increased dopamine levels in the brain [25, 26, 27].

All in all, there is insufficient evidence to claim that kava helps with mood symptoms of menopause and perimenopause. Larger, more robust clinical trials are needed to validate these findings.

4) Brain Function

A single dose of kava extract (300 mg) improved accuracy and performance in attention, visual processing, and working memory tasks in a small trial on 20 people [28].

In another trial on 12 people, kava extract (200 mg, 3x/day) slightly improved performance in a word recognition task [29].

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].

Because only two, very small clinical trials have been conducted, there is insufficient evidence to support the use of kava as a cognitive enhancer. Further clinical research is needed.

5) Treatment of Drug Addiction

Kava reduced the cravings for addictive drugs in drug-dependent patients in a pilot study [30].

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 may increase dopamine [31].

A single pilot study (which we couldn’t access for a critical analysis) is clearly insufficient to back the potential benefits of kava in treating drug addiction. More clinical research is required.

Animal and Cell Research (Lack of Evidence)

No clinical evidence supports the use of kava for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies should not be interpreted as supportive of any health benefit.

Brain Protection

Kavalactones extracted from kava prevented 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 may combat oxidative stress [32, 33, 34].

Epilepsy and Seizures

Kava helped treat seizures and epilepsy in rats. Alone and in combination with the antiepileptic drug diazepam, kava reduced motor activity, increased the seizure threshold, and enhanced 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 [35].

Anti-Inflammatory

In cell-based studies, kavain and flavokawains A and B inhibited NF-kB and decreased TNF-alpha, both of which play a central role in inflammation [36, 37].

Immunity Boost

In mice, flavokawains A and B stimulated white blood cells in the spleen, causing the secretion of cytokines IL-2 and TNF-alpha and increasing the level of immune T cells [38].

Cancer

Below, we will discuss some preliminary research on kava’s potential anticancer effects. It’s still in the animal and cell stage and further clinical studies have yet to determine if its extract may be useful in cancer therapies.

Do not under any circumstances attempt to replace conventional cancer therapies with kava or any other supplements. If you want to use it as a supportive measure, talk to your doctor to avoid any unexpected interactions.

Kava stopped the progression of bladder cancer and suppressed tumor growth in mice. Flavokawain A activated pathways (caspase-3/9 and Bax protein) that induce tumor cell death and inhibited proteins that prevent cell death (survivin) [39, 40].

Flavokawain B reduced prostate tumor growth, in part by reducing androgen receptors in prostate cells, in both mice and cell studies. Flavokawain B also killed tumor cells by activating the pathways that cause cell death (caspases and Bax) [41, 42].

Kava decreased breast cancer cell size, prevented their spreading, and increased their death. Flavokawain A, B, and a flavokawain derivative (FLS) increased the concentration of a protein that activates cell death (Bax) and inhibited two proteins needed for cell growth (PLK1 and FOXM1). Flavokawain A also cut off nutrient supply to tumors by inhibiting blood vessel formation and decreasing the levels of the glucose transporter GLUT1 [43, 44, 45].

Flavokawain B also inhibited the growth of colon cancer cells (through the release of cytochrome c and Bax/Bak protein) [46, 47].

Side Effects & Precautions

This list does not cover all possible side effects. Contact your doctor or pharmacist if you notice any other side effects.

Call your doctor for medical advice about side effects. In the US, you may report side effects to the FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada, you may report side effects to Health Canada at 1-866-234-2345.

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 [48, 49, 50, 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, 51].

Driving and operating heavy machinery is not recommended after consuming kava since kava may impair 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 [52].

There have been a few reported cases of kava consumption leading to hepatitis A (a virus transmitted through contaminated water) infection in the liver [53].

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, 54].

Whole kava extract inhibits cytochrome P450 enzymes (CYP1A2, CYP2C9, CYP2D6, CYP3A4, and CYP4A11), which break down many medications [55].

Common drugs that are broken down by CYP450 enzymes include:

Taking these medications in combination with kava could alter the effects of the medication, making it necessary to change the dosage. Always consult your doctor before supplementing with kava, especially if you are on a prescription medication [1].

Supplementation

Dosage

Because kava is not approved by the FDA for any condition, there is no official dose. Users and supplement manufacturers have established unofficial doses based on trial and error. Discuss with your doctor if kava may be useful as a complementary approach in your case and which dose you should take.

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

People using it for recreational purposes often take much higher doses, as much as 50-200 g/day of powdered extract [1].

User Reviews

The opinions expressed in this section are solely those of kava users, who may or may not have medical or scientific training. Their reviews do not represent the opinions of SelfHacked. SelfHacked does not endorse any specific product, service, or treatment.

Do not consider user experiences as medical advice. Never delay or disregard seeking professional medical advice from your doctor or other qualified healthcare providers because of something you have read on SelfHacked. We understand that reading individual, real-life experiences can be a helpful resource, but it is never a substitute for professional medical advice, diagnosis, or treatment from a qualified healthcare provider.

According to most users, kava root extract capsules provided excellent anxiety and stress relief and function well as a sleep aid. However, some people found that the effects were not strong enough to reduce anxiety and stress.

Some users preferred kava instant mix. They reported immediate effects lasting for around an hour. However, many of them warned that its strong taste is not for everyone.

Some users experienced a reverse tolerance after consuming kava or complained that it took too long (up to 3 weeks) until the full effects kicked in.

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About the Author

Carlos Tello

Carlos Tello

PhD (Molecular Biology)
Carlos received his PhD and MS from the Universidad de Sevilla.
Carlos spent 9 years in the laboratory investigating mineral transport in plants. He then started working as a freelancer, mainly in science writing, editing, and consulting. Carlos is passionate about learning the mechanisms behind biological processes and communicating science to both academic and non-academic audiences. He strongly believes that scientific literacy is crucial to maintain a healthy lifestyle and avoid falling for scams.

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