You're prescribed levithyroxibe (T4) as your thyroid is under active (hypothyroidism). Bulking / cutting doesn't matter, you need your medication to be in a eurythroid state.

If there's anything specific you want to know, feel free to drop a line on pm etc. I was over active, had my thyroid removed, now obviously on the same situation is you taking t4. Only difference with me is all of my t4 is artificial, you're just getting a little top up.

SDM is really knowledgeable about thyroid and thyroid meds. He really knows his shit if you need some solid advice.

I take 137mcg of levothyroxine every morning about 4 am I get up at 5:30 for the day. I've been blasting and cruising for 18 months. My body fat has gone down while weight has gone up. I have found that with 2ui/day of hgh 180mg/wk of test-c I can eat almost anything and not gain body fat. One thing that I have found out is that cortizol is our enemy and will pile fat onto our asses and gut as well as our jowles. Oranges and orange juice seem to reduce cortizol levels. I read that somewhere I will try to find it again and post a link for you.
you should do fine with your bulk without any adjustment to your medication. The extra test will alter your blood test results so be sure not to get bloods done when your bulking. I hope this helps... peace mk

There are a lot of people that use T3/T4 on a cutting cycle but where it really shines is on a bulking cycle. What I would suggest is that you have a good solid testosterone base to your cycle and then you can up your T3/T4 and along with that increase your calories by about 500 above maintenance. That combination will give you some very good quality lean gains. Don't forget to manage your E2 while you are uping your Test.

Check out allaboutpeptides.com being that t3 and t4 are peptides you can research there as well as email them with any questions.