Thyroid Hormone + Growth Hormone – If You Aren’t Using T4 with Your GH, You’re Not Doing It Right

By anthony roberts
Quite some time ago, I wrote a book on Anabolics, and since then, I’ve received quite a bit of feedback on it. Some of the information contained in the book is based on the 50-60 profiles I completed for Steroid.com’s main page. As a result, I get feedback on certain portions of the book from people who have read them online.
When someone takes the time to send an e-mail to Steroid.com or AnabolicBooks LLC, they’re screened, and eventually some of them make their way to my e-mail account. AnabolicBooks LLC is publisher- a little known fact is that my book is actually wasn’t edited by me, nor do I own the rights to any of it. When they forward an e-mail to me, I typically consider it very carefully, and reply to the original sender. If amendments or additions are useful for anything I’ve previously written (readers frequently send me recently published studies), I typically reply and thank the person for their help.
This time, something odd happened. I was forwarded an e-mail from AnabolicBooks, and the reader seemed to know what he was talking about, but (I thought) mistaken about interactions between Growth Hormone and Thyroid medication. I took a look at the e-mail, and knew that I could quickly find a study that I had saved previously, to send to the reader, to verify that the claims in my work on GH were sound.
In this particular case- James Daemon, PhD- was the reader, and was correct in his assessment of the interaction between thyroid hormone and Growth Hormone. And, in direct contradiction, so was I. Thyroid medication decreases the anabolic effect of Growth Hormone. And it increases it.
Huh?
There’re some leaps here, because research in some of the necessary areas is sketchy (or not done yet), but if you read the entirety of this article, you’ll learn how to get a significantly more gains from Growth Hormone, for pennies a day, by the addition of a readily available (and cheap) addition to it. And yeah, it’s a drug you can get anywhere on the ‘net, very easily. And no, it’s not a steroid.
In fact, I’ll go so far as to say you’re throwing away a substantial portion of your gains from growth hormone if you are not using this drug with it.
Ok…I’ll explain things a bit further. First, a brief explanation of Thyroid Hormone as well as Growth Hormone may be necessary.
Your thyroid gland secretes two hormones that are going to be of primary importance in understanding Thyroid/GH interaction. The first is thyroxine (T4) and the second is triiodothyronine (T3). T3 is frequently considered the physiologically active hormone, and consequently the one on which most athletes and bodybuilders focus their energies on. T4, on the other hand, is converted in peripheral tissue into T3 by the enzymes in the deiodinase group, of which there are three types- the three iodothyronine deiodinase either catalyze the initiation (D1, D2) or termination (D3) of thyroid hormone effects. The majority of the body’s T3 (about 80%) comes from this conversion via the first two types of deiodinase, while conversion to an inactive state is accomplished by the third type.
It’s important to note that not all of the body’s T4 is converted to T3, however- some remains unconverted. The secretion of T4 is under the control of Thyroid Stimulating Hormone (TSH) which is produced by the pituitary gland. TSH secretion is in turn controlled through release of Thyrotropin Releasing Hormone which is produced in your hypothalamus. So, when T3 levels go up, TSH secretion is suppressed, due to the body’s self regulatory system known as the “negative feedback loop” . This is also the mechanism whereby exogenous thyroid hormone suppresses natural thyroid hormone production. However, it should be noted that thyroid stimulating hormone (like all other hormones) can not work in a vacuum. TSH also requires the presence of Insulin or Insulin-like Growth Factor to stimulate thyroid function (1) When thyroid hormone is present without either insulin or IGF-1, it has no physiological effect (ibid).
Most people think that T3 is just a physiologically active hormone that regulates bodyfat setpoint and has some minor anabolic effects, but in actuality, in some cases of delayed growth in children, T3 is actually too low, while GH levels are normal, and this has a growth limiting effect on several tissues (2) This could be due to T3’s ability to stimulate the proliferation of IGF-1 mRNA in many tissues (which would, of course, be anabolic), or it could be due to the synergistic effect T3 has on GH, specifically on regulation of the growth hormone gene. Although it is largely overlooked in the world of performance enhancement, regulation of the growth hormone response is predominantly determined by positive control of growth hormone gene transcription which is proportional to the concentration of thyroid hormone-receptor complexes, which are influenced by T3 levels. (3)
At this point, just to give you a better understanding of what’s going on, I think it’s prudent to also give a brief explanation of Growth Hormone (GH) as well.
Your body’s GH is regulated by many internal factors, such as hormones and enzymes. hormones. A change in the level of your body’s GH output begins in the hypothalamus with somatostatin (SS) and growth hormone-releasing hormone (GHRH). Somatostatin exerts its effect at the pituitary to decrease GH output, while GHRH acts at the pituitary to increase GH output. Together these hormones regulate the level of GH you have in your body. In many cases, GH deficiency presents with a low level of T3, and normal T4(4). This is of course because conversion of T4-T3 is partially dependant on GH (and to some degree GH stimulated IGF-1), and it’s ability to stimulate that conversion process of T4 into T3.
Interestingly, the hypothalamus isn’t the only place where SS is contained; the thyroid gland also contains Somatostatin-producing cells. This is of interest to us, because in the case of the thyroid, it’s been noted that certain hormones which were previously thought only to govern GH secretion can also influence thyroid hormone output as well. SS can directly act to inhibit TSH secretion or it may act on the hypothalamus to inhibit TRHsecretion. So when you add GH into your body from an outside source, you are triggering the body into releasing SS, because your body no longer needs to produce its own supply of GH…and unfortunately, the release of SS can also inhibit TSH, and therefore limit the amount of T4 your body produces.
But that’s not the only interaction we see between the thyroid and Growth Hormone.
As we learned in high-school Biology class, the body likes to maintain homeostasis, or “normal” operating conditions. This is the body’s version of the status quo, and it fights like hell to maintain the comfort of the status quo (much like moderators on most steroid discussion boards). What we see with thyroid/GH interplay is that physiological levels of circulating thyroid hormones are necessary to maintain normal pituitary GH secretion, due to their directly stimulatory actions. However, when serum concentrations of thyroid hormone increase above the normal range we see an increase in hypothalamic somatostatin action, which suppresses pituitary GH secretion and overrides any stimulatory effects that the thyroid hormone may have had on GH. The suppression of GH secretion by thyroid hormones is probably mediated at the hypothalamic level by a decrease in GHRH release(5).
In addition, as IGF-I production isincreased in the hypothalamus after T3 administration and T3 may participate in IGF-1 mediated negative feedback of GH by triggeringeither increased somatostatin tone and/or decreased GHRH production (6). IGF, interestingly, has the ability to mediate some of T3’s effects independent of GH, but not to the same degree GH can (7.) In fact, IGF-I production isincreased in the hypothalamus after T3, administration it may plausibly participate in negative feedback by triggeringeither increased somatostatin tone and/or decreasedGHRHproduction.So we know that GH lowers T4 (more about this in a sec), but an increase in T3 upregulates GH receptors (8) as well as IGF-1 receptors (9,10).
As can be previously stated, and due to the ability of GH to convert inactive T4 into active T3, GH administration in healthy athletes shows us an entirely predicatble increase in mean free T3 (fT3), and a decrease in mean free T4 (fT4)levels.(11)