I'm sorry that I missed this and didn't reply before now.
Reading and interpreting studies can be difficult, especially when some seem to contradict one another, and its important to always look at things in context.
The study that you posted from the WADA website, here is part of the conclusion:
The ecdysterone administration led to increased serum IGF1 concentrations in comparison to the control group while thyroxin (T4) concentrations decreased.
Significantly higher increases in muscle mass were observed in those volunteers that were dosed with the ecdysterone supplements. Even more relevant with respect to sports performance, also significantly more pronounced increases in one-repetition bench press performance were observed.
These data underline the effectivity of an ecdysterone supplementation with respect to sports performance. We therefore strongly recommend to include ecdysterone in the list of prohibited substances and methods in sports to improve clean competition in the future. As the exact mechanism of action is not yet fully understood, we suggest to include it in class S1.2 “other anabolic agents”.
Context - it's pretty clear they are picking and choosing studies to present it in a way to add it to their prohibited substances list, as they state in the last 2 sentences.
Now, let's look at the main part that you are asking about specifically:
The ecdysterone administration led to increased serum IGF1 concentrations in comparison to the control group while thyroxin (T4) concentrations decreased.
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This is a case of where they are not telling the full story, because as mentioned above, they are trying to present it in a certain light.
As you know, hormones interact with and have relationships with other hormones - and what we are looking at here isn't necessarily Ecdysterone having an impact on T4, it is increasing IGF-1 having an impact on T4.
- Increasing IGF-1 levels may lead to decreased T4 levels because increased IGF-1 levels may stimulate the conversion of T4 into the more active form, T3.
- While IGF-1 can increase T3, studies on whether it directly affects T4 are mixed, with some showing an increase in T3 with no change in T4, while others show an increase in T3 and a decrease in T4.
In the real world, the likelihood of this happening to any noticeable degree (good or bad) is very unlikely.
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I have an endocrine condition and have to have bloodwork done regularly including T3, T4, Reverse T3, etc. and I have had bloodwork done on Ecdy-Plex. I went back and checked for you and there was no significant difference in any of my thyroid levels when I had it done on it, and I had it done 5 weeks into a cycle of it.
I hope that information helps.