yes and no
depends on how you eat while the slin is active. I was eating for bulk, and not watching my fat intake even when slin was active. I swear I literally felt like I put fat on OVNT when slin.
Last year I gain some major fat on slin, along with some muscle.
I just started slin again with more knowledge.
Now, I am eating absolutely 0 fat while slin is in and low fat when it's not. I am using 25mcg T3 also and I honestly believe I am losing fat and maintaining, if not, gaining some muscle-I am taking nothing but the slin and T3 at the moment. 5iu pre-workout and 10iu post. YES, I have all the carbs I need handy. I am usually pretty glycogenated (can I say that?) before I shoot to begin with.
So, eat NO FAT while slin is active and you should be OK, prolly wanna take ECA or the like just to be safe.
Good luck if you so choose...and make sure you have easy access carbs handy.
Rugger