T2 For Fat loss. Make Sure Its the Correct Version!
Posted on July 01 2018
I've written about the thyroid hormone metabolite diiodothyronine aka T2 before. Accordingly, you will probably know that it has long been thought of as an inactive byproduct of the thyroid hormone metabolism (read previous T2-articles). You will also be aware of the fact that research shows that (a) this is not the case and that (b) only one of its two forms, namely 3,5-diiodothyronine (3,5-T2) shares the fat burning, metabolic effects of its big brother triiodothyronine aka T3.
Just like me, you probably don't know, however, why supplement companies are still stupid enough to use both 3,5- and 3,3-diiodothyronine in their allegedly fat burning supplements - "stupid", because we already knew it has no effect and even more stupid, since a recent study from the Universidade de São Paulo and the Houston Methodist Research Institute has shown that it will, in total contrast to 3,5-T2, of which the latest research by da Silva Teixeira et al. shows that it will reduce the blood glucose levels independently of insulin sensitization, impair the metabolism of glucose.
Yes, you read that right: While 3,5-T2 burns fat (especially in the liver) and increases your metabolism, its cousin 3,3-T2 will do nothing for your BMR/RMR + glucose and fatty acid metabolism and can, on top of that, even impair your glucose metabolism and, as the data in Figure 1 shows, increase the amount of liver fat and food intake.
I guess this negative effect on your glucose metabolism alone should be reason enough to avoid supplements with the commonly used combination of 3,3- and 3,5-T2.
Plus: The fact that a 2015 study by Pietzner et al. suggests that, in healthy euthyroid human beings, there's a J-shaped correlation of circulating 3,5-T2 levels and glucose (p >> 0.05 for insulin, waist, and subc. fat) with the latter being more or less constant until a certain optimal 3,5-T2 level is achieved and the fasting glucose levels "explode" (see Figure to the left).
After all, you can only hope for the 3,5-T2 the Brazilian scientists who have been dabbling with diiodothyronines in previous studies, already, to counter the ill effects of 3,3-diiodothyronine (3,3-T2).
|Figure 2: (A) Fasting blood glucose, (B) glucose response during glucose tolerance test and (B) insulin levels in diet-induced obese mice according to treatment (da Silva Teixeira. 2016).
What's more, no supplement company can give you a guarantee that the 3,5-T3 in their products will fully counter the ill effects of 3,3-T2 on liver fat, the response to glucose tolerance tests, and the increased levels of insulin and appetite you can see in Figure 2 (and Figure 1, respectively) - no matter, how large the words "synergy" or "synergistically" are plastered all over the supplement bottle.