There is a lot of misinformation on the internet regarding cannabis and the liver, and some of it to be found on otherwise reputable sites concerned with liver health and alcoholism recovery which keep referencing studies from a variety of sources with conclusions which I find dubious. To begin with, there is no regularly observed change in the level of circulating liver enzyme levels in human subjects attributable to cannabis; it is not toxic to the liver. In patients with pre-existing liver disease like cirrrhosis or fatty liver ANY substance detoxified in the liver may begin to overwhelm the limited resources available, but cannabis appears to be generally safe even in that context. Both THC and CBD are metabolized by the cytochrome P450 system, although via different sub-enzymes. I don't think there is a significant difference in their hepatic metabolism from the point of view of liver health. The liver will signal it is unhappy by releasing the enzymes we measure using the standard blood chemistry tests. If using cannabis is associated with a rise in the levels of those enzymes it should be discontinued. If no rise is observed after using cannabis regularly for a few weeks then I'd find other things to worry about.