Kava and anxiety: What science says about the popular plant supplement

Kavasutra looks like most other bars in Manhattan’s East Village, with its welcoming neon sign and dimly lit, intimate atmosphere. But the “bar” is missing a key ingredient of the typical scene — alcohol. Instead, the establishment serves kava, a drink made from a root typically found in the Pacific Islands.

It’s also where, a few years ago, I had my first (and only, to date) experience with the drink. Since then its popularity has continued to boom, in part because of anecdotal claims that it reduces anxiety. Studies do suggest that kava supplements could have a small effect on reducing anxiety — but there are dangers linked to the extract as well.

Kava, made from the plant Piper methysticum, is also sold as pills and tinctures at drugstores, nature markets, and online. Bars and cafes serve it as an alcohol-free social lubricant, like CBD or mocktails.

You don’t sip kava, I was told when I tried it. You take it like a shot. It goes down chalky, and leaves a faint numb-tingle feeling in the throat, like the one after you eat pineapple or a kiwi. Later, on my way home, I remember a subtle feeling of calm washing over me. I texted my friend, saying I thought the earthy-concoction was finally working as intended. (It’s also possible, of course, that the mellow was simply the byproduct of a long day’s end.)

While it was fun to try something new, I wasn’t particularly compelled to head back for more. But there’s a reason why kava is on-trend: People claim that it’s a tool for dealing with anxiety, stress, and sleep problems. Some more far-fetched claims include that it can help with urinary tract infections, ADHD, and toothaches.

However, experts warn that kava can also be unhealthy, especially in large amounts, causing problems with the liver and muscle function. Here’s what science can currently say about the potential benefits of the extract — and its risks.

What is kava?

The plant kava — also called kava kava — comes from, P. methysticum and grows in the Western and South Pacific. It’s part of the same genus as pepper plants and vines. Concentrated in the roots of this particular pepper plant are organic compounds called kavalactones.

There are eighteen kavalactones that have been isolated and extracted from kava root, but most research focuses on the six kavalactones that are found in the highest concentration. Each of these is associated with individual effects, but when combined — like in a kava shot — they can induce the calming effect the drink is famous for.

Traditional kava ceremonies have been performed for centuries, and kava is consumed regularly in Fiji, Hawaii, and Polynesia during social and ceremonial events.

In the United States and Europe, the rise of kava started in the late 1990s when it was promoted as a “natural” alternative to anxiety drugs like Xanax and Valium. That kava-“boom” then dipped off for a bit less than a decade, until kava’s popularity returned around 2017.

Since then kava bars have popped up across the country. The place I visited in Manhattan, Kavasutra — for all its sleek city coolness — is part of a chain. There are other locations in Florida, Colorado, and Arizona. 

Why are people drinking this root?

In a word: anxiety.

According to Tracy Pingel, the owner of SquareRüt Kava Bar in Austin, Texas, drinking kava can quiet the mind. She told Rolling Stone that it shuts down “what I like to call that ‘mental talking in your head.’”

The active ingredients in kava, called kavalactones, have sedative, euphoric, and psychotropic properties. The kavalactone that causes relaxation is called kavain. Another kavalactone called desmethoxyyangonin causes euphoria by boosting dopamine levels.

Since kavalactones don’t affect the brain directly, the substance isn’t truly a sedative, explains kava researcher Vincent Lebot. He says that’s why drinking kava doesn’t actually alter one’s perception of reality.

Meanwhile, research does indicate that kava can (modestly) benefit people with generalized anxiety disorder (GAD). In a 2013 Journal of Clinical Psychopharmacology study participants with GAD took kava for six weeks, while a separate group took a placebo. After the trial, 37 percent of the kava group saw their symptoms eased, compared with 23 percent of the placebo group.

The results suggest that kava could have a bright future as a treatment for anxiety. In turn, the study’s researcher Jerome Sarris, a professor at Western Sydney University’s NICM Health Research Institute, said that kava could supplement other treatments. He emphasizes that it should be viewed as an additional tool, not a replacement for other anxiety treatments.

In the study, Sarris and his colleagues do note that branding the clinical trial as an “herbal treatment” for anxiety might have contributed to bias among participants. The study was also funded, in part, by a company that manufactures kava — though the researchers said the company didn’t have any influence on the study itself.

Meanwhile, in a 2018 review published in the Journal of Alternative and Complementary Medicine, researchers analyzed 12 studies that explored kava as a treatment for GAD — including Sarris’ paper. They found that while the current evidence is promising, it’s still “insufficient to confirm the effect of kava for GAD treatment beyond placebo.”

But beyond effectiveness alone, nutritionists and other experts say that there are some key side effects to consider if you’re thinking of trying kava.

Experts urge caution

Using large amounts of kava — at least, the kind you can buy in Western countries — can cause several negative side effects, including loss of muscle control and balance, double vision, skin problems (like dryness), and hepatoxicity, or liver damage.

Importantly, in the case of the liver damage, researchers know that these cases are associated with kava intake, but it’s not clear how the dosage amount or period of use act as contributing factors. 

Those problems aren’t associated with the forms of kava used traditionally by Pacific Islanders, notes the Australian Department of Health website. Rather, these issues stem from the kava-containing supplements sold outside of those traditional circles.

Lebot notes that many of the side effects described aren’t necessarily more intense than, say, those of caffeine. “If you abuse coffee, you might have side effects [too],” he says.

But in extreme cases, liver failure resulting from kava has led to serious cases, even death. A scientific review published in 2008 found that at least four people died out of eleven cases of extreme toxicity. Those were all associated with commercial products containing kava.

“Preliminary studies suggest possible serious organ system effects,” the researchers wrote. “The potential carcinogenicity of kava and its principal constituents are unknown.”

The Cochrane Library, an organization that reviews medical research, states that more rigorous studies with larger samples — and long-term safety studies — are needed to round out the true effects of the substance.

Regulating roots

Because of the risks involved with Western kava preparations, a number of Western countries have banned the substance: Germany, France, Switzerland, Australia, and Canada. (Later, Germany reversed its ban.)

Kava is legal in the United States, but the Food and Drug Administration has sent warning letters to several companies for improper labeling. In the past, the FDA has also warned consumers about the risks of liver damage.

So if you’re going to try kava, stick close to the source. The brewed variety seems to be relatively safe, at least compared with the pills and solutions sold as “herbal supplements” that might cause serious problems. Plus, assuming there’s a kava bar near you — the website Kalm With Kava has an interactive map — you can enjoy the experience with friends willing to try a mud-like pepper shot with you.