Kava, Honestly: What It Is, What the FDA Advisory Says, and How Much Is in Your Bottle

Kava comes up in two very different conversations. In one, it's a drink people in Fiji, Vanuatu and Tonga have shared for centuries. In the other, it's a supplement with a liver warning attached.

Both are accurate. This guide covers what kava is, what the warning is actually about, and what the number on a label means — including ours.

What kava is

Kava is made from the root of Piper methysticum, a pepper plant grown across the South Pacific. The active compounds are kavalactones — mainly kavain, dihydrokavain, methysticin, dihydromethysticin, yangonin and desmethoxyyangonin. Traditional preparation grinds the root and steeps it in water; the result is a bitter, earthy drink that numbs the mouth slightly.

Kava is legal to sell in the United States as a dietary ingredient. It is not a controlled substance, and it is not kratom — a confusion worth clearing up, since the two often sit on the same shelf. They are unrelated plants with unrelated chemistry.

The FDA advisory, and what it actually says

On 25 March 2002, the FDA issued a consumer advisory warning that kava-containing dietary supplements may be associated with severe liver injury. The reports behind it included hepatitis, cirrhosis and liver failure. One case in the US involved a previously healthy young woman who required a liver transplant.

That advisory still stands. The FDA revisited the literature in a 2020 scientific memorandum, and the NIH Office of Dietary Supplements continues to point consumers at it.

Two things are worth holding at once. Serious liver injury from kava appears to be rare, and researchers have argued about how many cases were caused by kava itself rather than by other medications, alcohol use, or poor-quality raw material. But rare is not zero, and the outcomes in the reported cases were severe.

What this means practically:

• Do not drink alcohol with kava. This is the single most repeated caution, and most of the concerning case reports involve other liver stressors.
• Do not take kava if you have liver problems or take medication that is hard on the liver.
• Stop and see a doctor if you notice yellowing of the eyes or skin, dark urine, unusual fatigue or pain under the right ribs.
• Do not drive after use. Kava can cause drowsiness and affect coordination.
• Not for use if pregnant or nursing, and not for anyone under 21.
• If you take prescription medication — particularly sedatives, benzodiazepines or anything processed by the liver — talk to a pharmacist or doctor first.

Noble kava, tudei kava, and why the plant part matters

Not all kava is the same plant material.

Noble kava refers to cultivars traditionally selected for daily drinking. Tudei ("two-day") cultivars are higher in certain kavalactones and other compounds, cheaper, and traditionally avoided for regular use — the name comes from how long the effects were said to linger. Vanuatu restricts kava exports to noble varieties.

The other variable is which part of the plant is used. Traditional preparation uses the root. Some of the products involved in European liver-injury reports used aerial parts — stems and leaves — and solvent extraction rather than water. Root-based, water-extracted kava has the longest record of traditional use.

If a seller can't tell you the cultivar and the plant part, that tells you something.

How to read a kavalactone number

The only number that matters on a kava product is total kavalactones per serving, not the weight of the product. A 500 mg tablet is not 500 mg of kavalactones.

For reference, traditional Pacific servings and clinical studies span a wide range — from a few dozen milligrams of kavalactones up to a few hundred per day in trial settings. Products on the US market vary just as widely, and plenty don't state the figure at all.

Our own number: Pura Vida Tranquil was tested by FESA Labs in August 2026 at 58.74 mg of total kavalactones per serving, broken down as dihydrokavain 19.90 mg, kavain plus dihydromethysticin 12.64 mg, methysticin 9.17 mg, desmethoxyyangonin 7.40 mg, yangonin 7.36 mg, and small amounts of flavokawain A and B. That sits at the modest end of the range.

The same lab panel screened it for kratom alkaloids, and mitragynine and 7-hydroxymitragynine both came back non-detect. You can read the whole report on our lab results page.

What kava is not

It isn't a sleep medication, it isn't a treatment for anxiety, and it isn't a substitute for anything a doctor has prescribed you. Studies on kava and anxiety exist and are genuinely mixed; we're not going to pretend otherwise to sell a product.

What we can say plainly: kava is a traditional botanical with a long record of use, a real and documented safety caution, and an active compound you can measure. If you want to try it, start low, skip the drinks, and buy from someone who will show you the lab report.

Sources

• NIH Office of Dietary Supplements — Kava
• US Food and Drug Administration — Consumer advisory on kava-containing dietary supplements, 25 March 2002; Scientific Memorandum on Kava, 2020

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease. For adults 21 and over. This article is general information, not medical advice.