generally methylated compounds are harder on your liver and usually kidneys than non-methylated ones. having said that, many of the tren ph/ps ARE hard on your liver and kidneys despite being non-methylated. the liver toxicity varies from compound to compound and effecive doses used. ex: mmv2 from legal gear is non-methylated and is very mild on your liver, epistane is methylated but more mild than many of the other methyls.
this is not a scientific explanation but making a compound 'methylated' basically makes the compound more bio available in your system due to your liver having to work harder to break the ph/ps down. instead of the liver destorying much of the compound as it passes through, much of the original compound remains to be converted thanks to the added methyl. this means a lower dose will be more effective because more of it will be readily converted in your body to the desired hormone. that is why in ps like tren x the -effective dose is 90-120mgs opposed to the methyl-1-test or epistane who have effective doses of 20 and 30mg.
this is what ive picked up on how methylated compounds work, so anyone correct me if im wrong on any of this