Kava

Effects

Overview

Kava or kawa (Piper methysticum: Latin "pepper" + Latinized Greek "intoxicating") is a crop of the western Pacific. The name kava refers to both the plant itself and the psychoactive beverage prepared from its rootstock. PW

Tropical evergreen shrub with large heart-shaped leaves and woody stems. Its thick roots are mashed or ground and made into a cold and bitter-tasting beverage used similarly to alcohol. It has a long history of ritual and recreational use in Pacific Polynesia and is now a common herbal product, used widely by those in certain societies as part of a 'Kava Culture.'[1] TS

Kava or kava kava (Piper methysticum: Latin 'pepper' and Latinized Greek 'intoxicating') is a plant in the pepper family, native to the Pacific Islands. The name kava is from Tongan and Marquesan, meaning 'bitter'. Kava can refer to either the plant or a psychoactive beverage made from its root. The beverage is a traditional ceremonial and recreational drink from Polynesia, Micronesia, and Melanesia. Nakamals and kava bars exist in many countries. Traditional kava is made by grinding fresh or dried kava root, mixing it with water or coconut milk, and straining it into a communal bowl. Outside the South Pacific, kava is typically prepared by soaking dried root powder in water and straining it. It is consumed socially for its psychoactive effects, comparable to those produced by alcohol but without significant cognitive impairment or addiction risk. Kava also produces a numbing sensation in the mouth.[2–7] WP

Kava consists of sterile cultivars clonally propagated from its wild ancestor, Piper wichmanii. It originated in northern Vanuatu, where it was domesticated by farmers around 3,000 years ago through selective cultivation. Historically, the beverage was made from fresh kava; preparation from dry kava emerged in response to the efforts of Christian missionaries in the 18th and 19th centuries to prohibit the drinking of kava.[8][9][10] WP

According to in vitro research, the pharmacological effects of kava stem primarily from six major kavalactones that modulate GABAA, dopamine, norepinephrine, and CB1 receptors, and inhibit MAO-B and ion channel mechanisms. Kava reduces short-term, situational anxiety, but its specific efficacy for generalized anxiety disorder appears to not be supported by the evidence.[2][6][8][11] WP

Many countries banned or restricted kava in 2002 due to safety concerns. The World Health Organization (WHO) subsequently reviewed kava's safety and concluded that moderate consumption of kava in its traditional form, as a water-based suspension of roots, presents an "acceptably low level of health risk". However, WHO and other health authorities have also concluded that consumption of kava extracts produced with organic solvents or excessive amounts of low-quality kava products may be linked to an increased risk of adverse health outcomes, including liver injury.[3][8][12][13][14] WP

A 2026 case report describes severe opioid-like withdrawal after heavy use of a product sold as “kava” whose label listed akuamma; testing of the same product found kratom derivatives and kavalactones. PubMed

History

Legal status

• In some countries, kava has been banned but in most, it is simply regulated. PW
• Australia - Kava is regulated by the National Code of Kava Management. Only 18 year olds may have it and can only possess 2 Kg in their baggage. PW
• United Kingdom - In the UK it is illegal to sell, supply or import any medicinal product containing kava for human consumption. It is legal to possess kava for personal use, or to import it for purposes other than human consumption (e.g. for animals). PW
• United States - In the U.S., kava was once noted as a potential "Liver Damaging substance" but this remark has since been archived by the FDA and kava is legal for sale, trade, possession, use, and all other uses. PW
• Canada - While Health Canada has similar remarks to the U.S. regarding kava, there is no ban on the substance. PW

Australia

In Australia, the supply of kava is regulated through the National Code of Kava Management. Travellers to Australia are allowed to bring up to 4 kg of kava in their baggage, provided they are at least 18 years old and the kava is in root or dried form. Commercial import of larger quantities is allowed under licence for medical or scientific purposes. These restrictions were introduced in 2007 after concern was raised about abuse of kava in indigenous communities. Initially, the import limit was 2 kg per person; it was raised to 4 kg in December 2019, and a pilot program allowing for commercial importation was implemented on 1 December 2021.[17][18][19] WP

The Australian Therapeutic Goods Administration has recommended no more than 250 mg of kavalactones be taken in a 24‑hour period.[20] WP

Kava possession is limited to 2 kg per adult in the Northern Territory. While it was previously banned in Western Australia, the Western Australian Health Department lifted the ban in February 2017, bringing Western Australia "into line with other States" where it has always remained legal, albeit closely regulated.[21][22][23] WP

Europe

Following discussions on the safety of certain pharmaceutical products derived from kava and sold in Germany, the EU imposed a temporary ban on imports of kava-based pharmaceutical products in 2002. The sale of kava plant became regulated in Switzerland, France, and in prepared form in the Netherlands. Some Pacific island states, which had been benefiting from the export of kava to the pharmaceutical companies, have attempted to overturn the EU ban on kava-based pharmaceutical products by invoking international trade agreements: Fiji, Samoa, Tonga, and Vanuatu argued at the WTO that the ban was imposed with insufficient evidence. The pressure prompted Germany to reconsider the evidence base for banning kava-based pharmaceutical products. On 10 June 2014, the German Administrative Court overturned the 2002 ban, making selling kava as a medicine legal, albeit strictly regulated; personal possession of kava has never been illegal. In Germany, kava-based pharmaceutical preparations are currently prescription drugs. Furthermore, patient and professional information brochures have been redesigned to warn about potential side effects. These strict measures have been opposed by some of the leading kava scientists. In early 2016, a court case was filed against the Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM/German Federal Institute for Drugs and Medical Devices), arguing that the new regulatory regime is too strict and not justified.[24–28] WP

In the United Kingdom, it is a criminal offence to sell, supply, or import any medicinal product containing kava for human consumption. It is legal to possess kava for personal use or to import it for purposes other than human consumption (e.g., for animals).[29] WP

Until August 2018, Poland was the only EU country with an "outright ban on kava" and where the mere possession of kava was prohibited and may have resulted in a prison sentence. Under the new legislation, kava is no longer listed among prohibited substances and it is therefore legal to possess, import, and consume the plant, but it remains illegal to sell it within Poland for the purpose of human consumption.[30][31][32] WP

In the Netherlands the ban was never lifted, and it is still prohibited to prepare, manufacture, or trade kava or goods containing kava.[33] WP

Due to safety concerns, including reports of hepatotoxicity and limitations in clinical evidence, the Committee on Herbal Medicinal Products (HMPC) concluded in 2017 that the benefit-risk balance for the oral use of kava in the treatment of anxiety disorders is unfavorable, and therefore a European Union herbal monograph could not be established.[34] WP

New zealand

When used traditionally, kava is regulated as a food under the Food Standards Code. Kava may also be used as an herbal remedy, where it is currently regulated by the Dietary Supplements Regulations. Only traditionally consumed forms and parts of the kava plant (i.e., pure roots of the kava plant, water extractions prepared from these roots) can legally be sold as food or dietary supplements in New Zealand. The aerial parts of the plant (growing up and out of the ground), unlike the roots, contain relatively small amounts of kavalactones; instead, they contain a mildly toxic alkaloid, pipermethysticine. The sale of aerial plant sections and non-water based extract is prohibited for the purpose of human consumption, but can be sold as an ingredient in cosmetics or other products not intended for human consumption.[35][36][37] WP

Canada

In 2002, Health Canada issued an order prohibiting the sale of any product containing kava. While the restrictions on kava were lifted in 2012, Health Canada lists five kava ingredients, as of 2017, and manufactured products containing kava or its extracts must be approved by the federal government before marketing.[38–41] WP

Singapore

Due to the risk of liver toxicity, the Health Sciences Authority of Singapore banned the sale of kava and its extracts in July 2002. The commercial sale, supply and import of "Piper methysticum (kava-kava), the active constituents of; kava pyrones (kavalactones); their quaternary compounds; their salts" remains banned in Singapore under the Poisons Act.[42][43] WP

United states

In the United States, kava is sold mainly as a dietary supplement and is not approved by the FDA as a drug. Manufacturers are responsible for ensuring product safety and proper labeling, while consumers are advised to consult healthcare professionals before using kava supplements.[2] WP

In 2002, the U.S. Food and Drug Administration warned that kava-containing dietary supplements, promoted for relaxation and other uses, may cause rare but severe liver injury—including hepatitis, cirrhosis, and liver failure—and advised consumers, especially those with liver issues or on liver-impacting drugs, to consult a doctor before use and to report any related adverse effects.[44] WP

The FDA concluded in 2020 that kava is not generally recognized as safe (GRAS) for use in conventional foods due to evidence of toxicity, potential liver damage, possible carcinogenicity, drug interactions, and a lack of sufficient safety data.[45][46] WP

Vanuatu

The Pacific island-state of Vanuatu has passed legislation to regulate the quality of its kava exports. Vanuatu prohibits the export or consumption of non-noble kava varieties or the parts of the plant that are unsuitable for consumption (such as leaves and stems).[47] WP

Pharmacology

Constituents

A total of 18 different kavalactones (or kavapyrones) have been identified to date, at least 15 of which are active. However, six of them, including kavain, dihydrokavain, methysticin, dihydromethysticin, yangonin, and desmethoxyyangonin, have been determined to be responsible for about 96% of the plant's pharmacological activity. Some minor constituents, including three chalcones—flavokavain A, flavokavain B, and flavokavain C—have also been identified, as well as a toxic alkaloid (not present in the consumable parts of the plant), pipermethystine. Alkaloids are present in the roots and leaves.[8][48][49][50] WP

Pharmacodynamics

The following pharmacological actions have been reported for kava and/or its major active constituents:[51] WP

• Potentiation of GABAA receptor activity (by kavain, dihydrokavain, methysticin, dihydromethysticin, and yangonin).[51] WP
• Inhibition of the reuptake of norepinephrine (by kavain and methysticin) and possibly also of dopamine (by kavain and desmethoxyyangonin).[51] WP
• Binding to the CB₁ receptor (by yangonin).[52] WP
• Inhibition of voltage-gated sodium channels and voltage-gated calcium channels (by kavain and methysticin).[51] WP
• Monoamine oxidase B reversible inhibition (by all six of the major kavalactones).[51] WP

Methanolic leaf extracts of Hawaiian kava cultivars showed stronger binding inhibition to several CNS receptors—including GABAA, dopamine D2, opioid (μ, δ), and histamine (H1, H2)—than root extracts, suggesting that compounds beyond the main kavalactones may contribute to the pharmacological effects of kava leaves.[53] WP

Detection

Recent usage of kava has been documented in forensic investigations by quantitation of kavain in blood specimens. The principal urinary metabolite, conjugated 4'-OH-kavain, is generally detectable for up to 48 hours.[54] WP

Pharmacokinetics

Kavalactones are quickly absorbed in the gut and vary in bioavailability. They primarily act on brain areas like the limbic system, amygdala, and reticular formation, but their exact molecular mechanisms are not yet fully understood.[55] WP

Data on the pharmacokinetics of kavalactones remain limited. In animal studies, particularly in rats, kavain—the primary kavalactone found in traditional kava preparations—was shown to be well absorbed, with an estimated bioavailability of approximately 50%. In humans, kavain undergoes extensive hepatic metabolism, primarily via cytochrome P450 (CYP) enzyme-mediated pathways, followed by further phase II biotransformation processes such as sulfonation, glucuronidation, and glutathione (GSH) conjugation.[7] WP

In rats administered a 100 mg/kg bodyweight dose of kavain, over 90% was eliminated within 72 hours through urine and feces, either as unchanged compound or as metabolites. No evidence of bioaccumulation has been observed in rats, mice, or humans.[7] WP

Chemistry

Pop culture

No references added yet.

References

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2. Journal / agency Kava. April 2025
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6. Other Kava. 2025-05-05
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8. Other Kava. 3 January 2018
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11. Other Kava for Generalized Anxiety Disorder. 2023
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18. Other Travelers from Fiji to Australia can now take more kava for social functions. 17 December 2019
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20. Other Kava fact sheet. April 2005
21. Other Kava. 12 December 2016
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27. Other Comeback unter strengen Auflagen. 16 August 2015
28. Other Joshua, Jane. New Kava Challenge. 17 February 2016
29. Other The Medicines for Human Use (Kava-kava) (Prohibition) Order 2002
30. Other Garae, Len. Kava banned in Poland. Dec 27, 2017
31. Other Rozporządzenie Ministra Zdrowia z dnia 17 sierpnia 2018 r. w sprawie wykazu substancji psychotropowych, środków odurzających oraz nowych substancji psychoaktywnych
32. Other Kava zalegalizowana. Marihuana będzie następna?
33. Other Koninkrijksrelaties, Ministerie van Binnenlandse Zaken en. Warenwetbesluit Kruidenpreparaten
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38. Journal / agency Marketed Health Products Directorate Heath Products and Foods Branch. Canadian Adverse Reaction Newsletter. 2002
39. Other Listing of Drugs Currently Regulated as New Drugs (The New Drugs List). 26 May 2016
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45. Journal / agency Scientific Memorandum: Kava. 2020-08-11
46. Other GRAS Determination for 'Awa
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