i think there has been too much of saying certain supplements can cause liver damage like kava, valerian, ashwagandha, even cbd (the one study where they gave mice an absurd amount of pure cbd) it makes me think it is almost like the medical and pharmacy industry wants to scare people away from any natural remedy and instead promote medications, i dont think any substance should be labeled as liver toxic after a few variable case reports or unrealistic studies
i notice alot of people say kava can cause liver problems, but ive recently done alot of research and it has been used for centuries in the pacific islands as a ceremonial and social beverage similar to alcohol but without the same side effects, which has later been found to be useful for certain conditions, anxiety, insomnia, and other uses as a sedative.
the one study that led to the panic about liver damage and it being banned in some european countries was using improperly extracted kavalactones (alcohol extraction vs water which is the traditional way). also some of the people in the study had preexisting liver problems and use alcohol as well which interacts with kava. overall there is alot that could go wrong studying an herb that at the time they didnt have alot of knowledge about and considering all the processes that go on that can change the kava from its natural state.
also kava extracts are not kava. kava is the name for the traditionally prepared drink from straining and kneading the noble kava root into water (only noble kava root is safe for consumption, tudei kava and kava leaves and stems are not), many of the extracts contain kava root of unknown origin (possibly containing tudei or above ground plant matter) extracted using alcohol which add to it possibly being bad for the liver and can bring out more of the kavalactones that are not found when just water or milk (which is sometimes used as the fat can pull out more kava) is used.
there is a community on reddit for kava where much more information can be found as well as to know the trusted vendors that provide noble kava root and user reviews and experiences good and bad as not everyone who consumes kava enjoys it as everyone is different. kava extracts are advised against.
the country that originally banned kava (germany) has unbanned it even though now some of the other european countries that followed germany in banning originally have still kept it banned.
in U.S.A. and many other countries kava is legal and there are no restrictions on it.
kava just like any medication or supplement has possible negative side effects associated with heavy consumption which are usually related to digestion like nausea, stomach discomfort, or dermopathy, certain medication interactions which is common with many supplements.
more common effects of normal use are temporary mouth numbing, and sedation.
real kava is not going to destroy your liver from reasonable use just like how safely drinking alcohol wont . the safety of kava from a scientific standpoint is still controversial as studies dont account for any pre-existing or comorbid condition and it is never said what type of kava or the content of the many variable kavalactones is being used.
really if you know what you are getting i believe it is as safe as many other things and can really be useful to some.