The Unwinder is reader-supported, meaning we may earn an affiliate commission if you buy through a link from our site.


What You Need To Know About Kava Side Effects: Kava Headache, Kava And Liver, And More

Kava is an herb from the Pacific Islands which has psychoactive effects, most commonly used for sedation and euphoria, playing a social role similar to alcohol in other cultures. Kava has recently become popular in Western culture as, when drunk, it also decreases social anxiety and relaxes the mind, similar to the effects of alcohol.

Kava Side Effect Profile

  • Kava headache: some users report a headache, which some users believe is caused by dehydration from taking kava
  • Kava face swelling: one study found that long-term kava users were more likely to complain of a puffy face than non-users, though this was not seen in Western users
  • Kava dermopathy: kava skin rash is a more common side effect seen in over half of traditional users which presents as dry, flaky skin or a rash
  • Kava drug interactions: kavalactones, an active ingredient in kava, can either block certain drug metabolic pathways, hampering drug efficacy, or synergise with drugs. Best to talk to your doctor before combining kava with prescription drugs.
  • Kava hepatotoxic: some case studies report hepatotoxic symptoms, such as jaundice and liver failure ー this mainly occurs in frequent, heavy users, people who combine kava with alcohol, or pregnant women
  • Kava cognitive dysfunction: clinical trials found that the sedative effect can impair cognitive function.  This impairment is typically minor, but it’s worsened if you take alcohol and kava together

Kava Dermopathy

A dry, flaky kava skin rash is a chronic effect in heavy, regular consumers. The reason for this dermopathy remains disputed. Don’t worry though; you would have to consume a lot of kava for a long time for this to show up, so it’s mainly seen in societies where kava is traditionally consumed.

Kava Interactions

Kava can either interact or sometimes interfere with drug metabolism. Notably, kava will have an additive, if not synergistic, effect with other depressants and should not be combined with depressants such as anti-anxiety or anti-insomnia drugs without consulting a doctor. 

Kava may also inhibit or potentiate medication for Parkinson’s disease, anticoagulants, and antiretroviral treatment for HIV.

Kava Overdose: How Much Kava Is Too Much?

Can you overdose on kava? Yes. A high dose or overdose normally exceeds 250mg of kavalactones, though the effects of an overdose may occur at a lower dose depending on the person. Taking a high dose accidentally is unlikely to cause you harm. 

However, if you do experience an overdose, you may feel your heart speeding up, get nauseous, drowsy, numb around the mouth, and your movements might be uncoordinated.  Unlike with alcohol, there seems to be no risk of immediate death by kava poisoning.

Kava Liver Damage: Does Kava Cause Liver Damage?

It can be, though less so than alcohol. Liver toxicity is most often seen in chronic heavy users, or people with pre-existing liver damage. You must also avoid taking poor-quality kava as this can contain a build-up of hepatotoxins which will damage your liver.  

The extraction method also determines whether your kava product could damage your liver. Ethanol-based (“hydroethanolic”) extraction methods make it worse, however contrary to previous medical belief, the traditional aqueous extraction methods can be hepatotoxic too.

Alcohol And Kava

Mixing kava and alcohol is not advised due to its potential for liver damage. In general, users take kava as a substitute for alcohol. Like alcohol, kava is a depressant and it slows down your mind and body, so if taken together, you will also feel very drowsy and lose your normal reflexes.

Kava Addiction

Is kava addictive? No. Kava is generally considered non-addictive, but tolerance does occur after prolonged use. It can also become habit-forming in people who start to rely on it to relax. This might exist in the form of cravings as one of the active ingredients of kava, kavapyrones, bind to sites in the brain associated with craving and addiction.

Kava And Pregnancy

You should avoid taking kava throughout pregnancy and while breastfeeding as there is uncertainty concerning liver health. Kava may also harm the unborn baby’s central nervous system (CNS) resulting in neonatal CNS depression which presents as a reduced heart rate, low breathing rate and blue lips — this condition is harmful in the long-term. 

Kava And Driving

At high doses, kava can cause drowsiness which may affect driving. So far, it appears to be much less of a hazard than alcohol. One study found no impairment from high doses of kava, however it’s unclear if the dosages used were really as high as a heavy kava user would consume. If you feel drowsy, you’re impaired and shouldn’t be on the road. 

Kava Reverse Tolerance

Reverse tolerance is when the user experiences a stronger effect each successive dose. Anecdotally, some people report this. It’s unclear how it could possibly occur though, and most studies find tolerance instead. Ultimately, you’ll just have to see for yourself.  

Is Kava Legal In The US?

Kava is totally legal in the U.S. Some countries, mainly in Europe, regulate it more heavily due to kava’s hepatotoxicity concerns — Poland is the only country to ban it altogether.

How Long Does Kava Stay In Your System?

Kava’s half-life is 9 hours which means that kava stays in your system for about a day. You can expect the effects of Kava to peak at around 2 hours and the effects will fade noticeably after anywhere from four to ten hours depending on dosage.

Does Kava Show Up On A Drug Test?

No. It’s not regulated in the U.S. Even in countries where it is, kava isn’t tested for. 

If you’re still interested in kava, we have researched the best kava products on the market.

Looking To Buy Kava? Read Our Review Of The 5 Best Kava Products

Feature image by Arthur Chapman on Flickr

About the author

Lucy is a UK-based freelance writer focusing on biological content, whether it may involve animal biology or health and well being. Having achieved a First Class Zoology degree at the University of Bristol, Lucy has a diverse knowledge base and enjoys writing for others. Lucy is also a medical student in London who enjoys, in her free time, weight lifting at the gym or hiking along precarious routes in the great outdoors.

Leave a Reply

Your email address will not be published. Required fields are marked *