Well that's the $64 question now isn't it. The more t3 you use the more fat you lose its maybe not linear but its established. Problem for many is higher doses are harder to live with and then there's the potential for wasting. If you are in content prep or maybe on reduced cals/carbs massively high doses might eat muscle. Now granted with a lot of protein and adequate aas this probably can be negated. It seems like 100mcg for many people is the meridian point. Less than that and yes you're probably taking mostly fat loss with little impact/worry about your muscle. It does vary. Like I mentioned I'm just at 50mcg ED split 25x2 and that's mild enough to live with but effective enough to be worthwhile. I suppose I'd even be ok adding a third 25mcg and moving total dose to 75mcg but that is as far as I'd care to go. But then again I'm not in contest prep now either.