This is an herb that has been used hundreds if not thousands of years for all sort of liver ailments.
It may be high in salicylate, not sure, and certainly it's not for everyone.
When I first got into about 15? years ago it was under guidance of a kinesiologist (not a fan anymore of kinesiology). I tested for an entire bottle of twinlab silymarin per day. This turned out to be really really good and it made a huge difference for me ending Sugar cravings in short order.
Any lower dose would have done nothing at the time. So I would say take silymarin not milk thistle, and just start slowly increasing until you feel something.
Also I have heard from some practitoners that they don't use milk thistle until the liver is cleared out via flushes or coffee enemas or whatever your method is.