Wow, more great contributions. This may be the best thread of all-time on this board.
1) I agree with the "researcher" who said that sometimes the establishment doesn't know squat. To that, I would add "especially the medical establishment", which is driven by insurers and which is risk-averse, even when they DO know something.
2) The difference between iron and T3/T4 is that iron is a nutrient, whereas T3/T4 are hormones; iron is not "produced" in the body, its intake is required by everyone to maintain life and health--so intaking some iron is universal, no matter from where it comes, and the amount varies according to individual requirements, but intaking T3/T4 is NOT universal.
What is the essential difference? You would have to believe (and I do believe) that with nutrients, if there is a deficiency, the body will send signals to the organism to seek intake to correct the deficiency--basically, hunger, and cravings. The body will then, on its own (assuming normal health), regulate the intake to the level that is required. It is an automatic process.
What is the biological response to hypothyroidism, in terms of adaptive responses? I know there are all sorts of symptoms of hypothyroidism, depending on its stage and its cause(s), but one would think that there are biological responses to correct the imbalance, as it is the integrated hormonal control system that is affected. Go out and eat something with T3 or T4 in it? Can it be absorbed if taken in? If so, does it reach receptors intact?
Since you used iron as the example, I will tell you something--for one week a month, my wife goes NUTS for red meat and spinach. It might have been conditioned over 40+ years, it might be automatic, or it might be a combination of both--but she needs it, and will kill to get it.
Sure there are nutrients in there other than iron, but let's assume that iron is the critical micronutrient.
Is there any similar mechanism experienced by those with hypothyroidism, at any level of hypothyroidism, and does it relate to the natural intake of T3/T4? In my admittedly uneducated opinion, if the "hypothyroidism" was genuine "clinical" hypothyroidism, there would be some deficit to normal function that the body would try to rectify on its own, through some mechanism or other--for instance, eating more or differently, sleeping more, training less, drinking more, whatever.
Again, if the CAUSE of the hypothyroidism is the performance of training itself, and if that hypothyroidism diminishes training performance, then pharmacologic correction of the hypothyroidism will by definition enhance that performance. The difference between T3/T4 and iron is that, AFAIK, nobody NEEDS to take concentrated iron supplementation, enough is available from natural sources if prepared correctly and eaten with foods containing transport-enabling compounds and not with those containing compounds that inhibit uptake, to compensate for any reasonable deficiency.
However, if the cause of that iron deficiency is training itself, then an argument could be made that the situation is exactly analogous to the situation where hypothyroidism results from training--except that with iron deficiency, even if you couldn't correct completely using natural sources, you could correct somewhat, meaning that you would naturally find the level of training that your body and habits can support, and any increased level of training would be enabled by an increased intake and uptake of iron; but with hypothyroidism, you couldn't correct naturally in any way that would result in an increased level of training--you would have to decrease your training level in order to regain homeostasis.
So, as far as hypothyroidism goes, pharmacologic intervention results in training advantage that is not achievable in any measure by natural means, which is totally different from the situation of an iron deficiency.
Unless, again, you can get T3/T4 from natural sources.
Same thing goes for other hormones that are produced in the body. Can you ingest testosterone or HGH, and will it be absorbed into the blood unchanged? I really have no idea.
Would eating mountain oysters temporarily increase your circulating testosterone? Again, I really have no idea.
Hopefully I won't be craving those oysters any time soon.