Kava (Piper methysticum)

Kava (Piper methysticum) is a tall shrub in the pepper family native to the Pacific islands, where it's traditionally used in ceremonies for relaxation. Here's what to know about kava.

How Do People Use Kava?

Traditionally, people use kava root to make beverages that cause mild to moderate sedation and feelings of euphoria. In some traditional cultures, people drink kava like those in other parts of the world drink coffee.

Now that kava has become more widely known, many people buy kava supplements for the plant's purported ability to reduce anxiety.

Kava Health Benefits

Alternative medicine practitioners use kava as a natural anxiolytic (anxiety-reducing) drug. It may also improve sleep in people with insomnia, often with fewer side effects than pharmaceutical or over-the-counter sleep aids.

The compounds in kava root believed to offer mood-altering properties are called kavalactones, of which 18 have been identified thus far. Little research has been done to pinpoint their exact mechanisms of action or evaluate which compounds are more active than others.

Anxiety

The current body of evidence suggests that kava may aid in the treatment of anxiety.

• In a 2002 review of studies involving seven clinical trials and 645 people, kava was deemed an "effective symptomatic treatment option for anxiety," even though the effect was considered "small" by the researchers.
• The findings were supported by a 2011 review from Australia in which kava was considered more effective in treating generalized anxiety disorder (GAD) than a placebo. With that being said, a traditional kava beverage was recommended over supplements for safety reasons, along with regular liver enzyme testing to avoid toxicity.
• A 2013 randomized controlled trial found that kava was effective in the treatment of generalized anxiety disorder. The results showed a significant reduction in anxiety and by the end of the trial, 26% of participants in the kava group experienced remission from their anxiety symptoms.
• A 2023 review echoed these results, concluding that current research on kava as an anxiety treatment is promising. However, the researchers cautioned that, as kava continues its rise in popularity, more research is needed on such issues as possible drug interactions, long-term effects, and efficacy compared to pharmaceuticals.

Insomnia

Most of the research devoted to the use of kava for insomnia is limited to animal studies. It is believed that a specific type of kavalactone, called kevain, may provide the drug's sedative effect.

Despite the promising results, the conclusions were undermined by the subjective nature of "quality of sleep" questionnaire. Based on the study measures, even people provided a placebo had significant improvements in sleep.

Inflammation

Kava also has anti-inflammatory properties, which might help with conditions in which inflammation plays a role. Some research suggests that modifying kava compounds might increase these anti-inflammatory effects. However, more research is needed, and some reports suggest that kava exposure can induce an inflammatory response. 

Cancer

A 2019 review of 39 studies revealed promising results in preventing and treating some cancers. Many other studies showed that kava had possible preventative effects on lung, prostate, colon, and urothelial cells as well. However, researchers caution that more research is needed to understand kava's mechanism of action and its effects in humans.

Side Effects of Kava

The use of kava remains controversial. Proponents believe that kava is safe for the short-term treatment of anxiety; others contend that the potential risks outweigh the benefits.

Even for short-term use, side effects such as indigestion, mouth numbness, rash, headache, drowsiness, and visual disturbances are common. The consequences of long-term use may, in some cases, be catastrophic.

Liver Damage

In March 2002, the U.S. Food and Drug Administration (FDA) warned consumers and health professionals about the risk of liver damage associated with kava use. Case reports have linked kava with liver toxicity, including hepatitis, cirrhosis, liver failure, and even death. 

Many of these cases were linked to pre-existing liver disease, excessive kava doses, and heavy alcohol use. It is still unclear whether the liver toxicity was the result of kavalactones, contaminants found in low-quality extracts, or the organic solvents (such as acetone or ethanol) used to make kava extracts and supplements.

Even though the WHO suggests that water-based kava beverages are "safer," the agency concedes that moderate to heavy consumption can significantly raise liver enzymes. The WHO also warned that toxicity appears linked to the quality of the raw kava root, contamination of the root during storage, and the use of other herbal drugs with kava.

In the aftermath of the warning, several countries have restricted the sale of kava within their borders. To date, only Germany, Canada, Poland, and Switzerland have banned the use of kava in any form. In the United States, kava is classified as a dietary supplement and can be purchased for personal use legally.

Precautions and Contraindications

Although kava in its traditional form poses an "acceptably low level of health risk" according to the World Health Organization (WHO), kava extracts and supplements may cause liver toxicity if overused or consumed on an ongoing basis.

If you intend to use kava for recreational or medicinal purpose, there are several things you should consider beforehand:

• Kava's effect on the neurological system is poorly understood. As such, it should not be used in people with clinical depression, bipolar disorder, or schizophrenia.
• Kava should be avoided in people with Parkinson's disease as it can potentially make the symptoms worse.
• Kava may interfere with blood clotting. It should not be used by people with bleeding disorders. You would also need to stop using kava at least two weeks before surgery to avoid excessive bleeding.
• Kava can cause drowsiness and impair your judgment, reflexes, and visual acuity. Do not use kava if you plan to drive or operate heavy machinery.
• Kava should be avoided in people with alcoholism, liver disease, pulmonary hypertension, low blood pressure (hypotension), or kidney disease.

Due to the lack of safety research, kava should never be used in children, pregnant women, or nursing mothers. Some studies have suggested that kava can be readily transmitted in breastmilk.

Drug Interactions

Kava can interact with several drugs and supplements. It may enhance the effects of the second drug or reduce those effects by competing for CYP450, the liver enzymes that metabolize kava.

Speak with your doctor if you are using (or intend to use) kava with any of the following medications:

• Sedatives and over-the-counter sleep aids
• Tricyclic antidepressants like Tofranil (imipramine)
• Monoamine oxidase inhibitors (MAOI) used to treat depression
• Benzodiazepines like Valium (diazepam) or Ativan (lorazepam) used to treat anxiety
• Diuretics ("water pills") like Lasix (furosemide)
• Blood thinners like Coumadin (warfarin) or Plavix (clopidogrel)
• Levodopa used to treat Parkinson's disease
• Proton pump inhibitors like Prevacid (lansoprazole) and Prilosec (omeprazole)
• Antipsychotics like Abilify (aripiprazole), Clozaril (clozapine), and Seroquel (quetiapine)

Dosage and Preparation

There are no guidelines for the appropriate use of kava. Kava is generally sold in the United States in capsule, soft gel caps, extract, powder, and tea forms. There are also "wild-crafted" dried roots used to make tinctures, teas, and beverages.

Most capsule formulations are offered in doses ranging from 50 milligrams to 100 milligrams. Most experts recommend that you take no more than 250 milligrams per day and limit your use to no more than three months.

What to Look For

Kava is largely unregulated in the United States, but don't assume kava is safe. The classification simply means that the manufacturer is responsible for ensuring the safety of the supplement, not the FDA. Although this relieves the manufacturer of the burden of clinical research, it can leave the consumer vulnerable to harm, both known and unknown.

What a manufacturer cannot do is market their supplements as a cure for any disease or medical condition. This doesn't mean the manufacturer can't suggest possible health benefits; many do. To better protect yourself, try to not be swayed by health claims that may or may not be true no matter how desperate you are for relief.

Because the quality and safety of kava can vary from one brand to the next, stick with manufacturers you know and trust. Buy products that are certified organic under the regulations of the U.S. Department of Agriculture (USDA). This is especially true of wild-crafted dried kava.

Other Questions About Kava

Given its rise in popularity and usage beyond the South Pacific, here are a few things you might wonder about kava.

How do I make kava tea or beverage?

Traditionally, kava drinks in the South Pacific are made from fresh root that is chewed or pulverized before water is strained through the fibrous pulp.

Although fresh kava root is rarely available in the United States, you can make it make it with dried kava. You'll need cheesecloth, a tea strainer, and some wild-crafted kava chips or powder (available online or in specialty stores).

To make a 6- to 8-ounce glass of traditional kava drink:

1. Put 1/4 to 1/3 cup wild-crafted kava in a piece of cheesecloth. Tie it into a loose bundle with string.
2. Heat 1 cup water until warm to the touch.
3. Place the kava bundle in a small bowl and cover it with the warm water.
4. Knead and squeeze the bundle for 10 to 15 minutes, applying pressure.
5. Pour the liquid through a tea strainer into a glass and drink.

Does kava produce a high?

Taken in normal doses, kava may help induce a sense of well-being and reduce anxiety. It does not necessarily produce a "high," but some people may experience pleasant feelings or a sense of calm and relaxation. Higher doses may produce more significant effects but should be avoided due to the serious risk of liver damage.

What does kava do to the brain?

Although kava's neurological effects are well-recognized, their exact mechanisms remain poorly understood. In the brain, kava modulates gamma-aminobutyric acid (GABA) receptors and inhibits monoamine oxidase B. Specific kava compounds may also affect dopamine levels, hippocampal neurons, and acetylcholinesterase,

Some research has shown that kava may have neuroprotective effects.