ok so maybe this could be the answer, or at least part of the equation and would make perfect sense!
ANABOLIC STEROID USAGE AND THYROID SUPPRESSION
Patrick Arnold
[...]
Bodybuilders who use large amounts of anabolic steroids often report lethargy as a side effect. Sleepiness, irritability, and foggy-headness are commonly reported by users of some of the more powerful anabolic steroids in large dosages. The cause of this lethargy has been the subject of debate in the performance-enhancement drug community, and the solution may be multifactorial. Published studies have given reason to suspect that thyroid hormone suppression may be one of these factors.
THYROID HORMONES
There are two major thyroid hormones, T4 and T3. T3 is considered the most active thyroid hormone, and its job is to act as a sort of ter regulator of every major aspect of metabolism- from protein thesis to carbohydrate and fat oxidation. T3 acts in general as a metabolic stimulator, and in addition to its influence on how the uses fuel for energy and tissue building, it also works to generate heat production (thermogenesis) via enhancement of uncoupling protein 1 (UCP-1) expression in the liver.
The production of too much thyroid hormone (hyperthyroidism) and too little thyroid hormone (hypothyroidism) are both undesirable conditions. Hyperthyroidism leads to overstimulation of the nervous system (resulting in elevated heart rate and nervousness), as well loss of lean body mass due to protein catabolism. Hypothyroidism; the other hand, leads to depression and fatigue, as well as other symptoms such as joint pain, sensitivity to cold, and fat gain.
ANABOLIC STEROIDS AND THYROID SUPPRESSION
As I stated in my introduction, published studies have confirmed that anabolic steroid use can suppress thyroid hormone levels in the blood. It appears that this is not due so much to a decrease in the production of the main thyroid hormone (T4) in the thyroid gland, however. What really is the culprit of the suppression is debatable, as different studies have found different things. Two things are clear, though. The levels of total and free active thyroid hormone (T3) are decreased with anabolic steroid use, and T4 thyroid hormone-binding globulin levels are markedly elevated. However, free T4 appears to be unchanged, as does TSH, which is the hormone that your brain produces to stimulate thyroid hormone production in the thyroid gland. So what is happening is not entirely clear. It may be a combination of disrupted conversion of T4 to T3 and/or interference of bioavailable T4 levels by excessive T4 thyroid hormone-binding globulin. Whatever the case, levels of the active thyroid hormoneT3 can be suppressed by anabolic steroid use- particularly at higher dosages. Such suppression can interfere with maximum muscle growth from a cycle, as optimal protein synthesis activity is dependent upon ideal T3 levels in the body.
It is interesting to note that bodybuilders have discovered by trial and error that thyroid hormone supplementation leads to greater gains during a cycle. I am pretty sure that this anecdotal discovery was made without the knowledge that AAS (anabolic-androgenic steroid) usage is thyroid suppressive.
