Well, the evidence is pretty conclusive that even at low doses, sylmarin inhibits 2 of the 3 pathways to PGF2a synthesis, which is ONE (an important one, but just one nonetheless) of the many ways in which AAS increase the muscles' size & strength. This in turn increases the rationale for non-methylated AAS cycles.
During the first 2 weeks of PCT, your natural production of AAS is negligible, so sylmarin's inhibition of PGF2a synthesis isn't a dramatic thing to undergo. OTOH, later during PCT you do want as much of the effects that your natty test will provide. This is absolutely essential to keeping gains.
Now, ALA is also a hepatoprotectant that AFAIK does NOT in any way impede anabolism. It does actually promote anabolism slightly, with its nutrient partitioning properties. N-acetyl-cysteine, one of the most potent hepatoprotectors, does impede anabolism, but only through ONE of the three pathways to PGF2a synthesis.
All these things induce the conclusion that MT is best when used only when necessary, preloading before the methyls, during the cycle, and stopping after 1 week of PCT or so. NAC, IMO, should be started at the same time as the methyls, as it goes to work right away. IMO NAC can be run through PCT. Of course ALA should IMO be a staple to anyone who trains hard so that's that.
A footnote is that MT can be stressful to the liver if taken only sporadically. It is best to start a course and keep it going rather than go on and off, which can actually increase the damage from hepatotoxic substances. Not so with either NAC or ALA.
Of course, I'm always looking to learn more so please someone correct me if I'm wrong.
