T3 and muscle catabolism?

I have never taken T3 before and was wondering about its chracteristics if it may hinder and or eat hard earned muscle if NOT cycled with anything else but only with a low dose of test cyp for HRT purposes (100mg wkly, until doc will up it) and rHGH @ 3iu's ed? I am not looking to bulk but maintain my definition with a loss of b/f. After some research some have said if used alone it will grab the amino acid pool from muscle which we all know is not a good thing. Any thoughts?

Thanks Red If I decide to run it I was planning on that 12.5mcgs but not sure if I should run it ed or 5 on 2 off which in 2 weeks thats what I am going to do 4iu's HGH. Should I only do cycle it for 1 month then stop?