reguarding the use of T4 / T3 when using HGH, i found this post by RedBaron:
I have used HGH over the course of about 8 years now. I have ran it in about every conceivable way, and with every conceivable support supplements and in conjunction with cycles. I have used it with T3, T4, T3+T4 (Armour Thyroid), and also without any thyroid assist at all.
In my experience, I would say that the need for thyroid supplements in conjunction with HGH has been overstated by quite a bit. It is true that HGH can have a short term effect on your thyroid. It is also true that in some cases your thyroid never drops out of the normal range, and in most cases even if it does it is a short-term event and returns to normal inside a couple of months.
If you wish to use T4 in lieu of T3, using it at ~4 times the dose will equate to roughly the same benefit as T3, assuming you have adequate minerals and other support supplements to foster a good conversion from T4 to T3. In my experience, as well as the experience of several other BB's that have tried both, there isn't a noticeable benefit to T4 supplementation over T3, and certainly thyroid supplementation is NOT an absolute necessity for HGH use.
Whenever you read articles such as this, keep in mind they put forth some ideas to consider, but realize that in many cases (this one too) the gentlemen writing these articles actually have very little to zero experience with HGH and thyroid supplements ... it makes for a nice article to sell, but doesn't necessarily equate to real world results. Real world experimentation seems to indicate that T4 isn't superior to T3, and certainly neither have to be included in every cycle. As in most things, theories are just that ... a few here and there actually pan out, most end up not holding up in real trials.
I use T3 for additional protein synthesis, and for a slight metabolic boost. In certain cycles and for specific goals it is a worthy addition to a cycle. I have probably used more cycles without any thyroid supplementation than ones with. One thing is clear after much experimentation ... HGH works fine minus exogenous use of T4 ... there is no question in my mind.