When I first supplemented thyroid hormone a few years ago, I was puzzled by the fact that I don't respond to it. Cynomel, cynoplus, Thiroyd (NDT Thailand),... It's like eating a sugar pill, no response in terms of mood/heart rate/temperature, etc. I tried a range of doses, from less than 1/8th of pill to several pills at once. I could not make sense of this. Posting about this experience on this forum, only a couple members seemed to relate to the experience. It seems however that in recent years, more people have started writing about it on the internet.
From Wikipedia:
https://en.wikipedia.org/wiki/Thyroid_hormone_resistance
From Dr Lowe:
http://web.archive.org/web/20101030202007/http://drlowe.com/QandA/askdrlowe/resistnc.htm
Dr Lowe's reply makes sense to me, it seems like supplementing the thyroid can suppress my TSH to near zero and yet it does nothing. However, I have never tried the very high doses recommended in this situation.
On other forums it seems a few users have the same situation:
https://healthunlocked.com/thyroiduk/posts/130845602/no-response-to-high-dose-thyroxine-why
https://healthunlocked.com/thyroiduk/posts/131285373/high-dose-t3.-no-response.-thoughts
You'll see in the discussion one recommends to read Recovering with T3 from Paul Robinson.
A few more links to articles:
http://www.thyroidresistance.com/thyroid-resistance/
From Wikipedia:
Thyroid hormone resistance (sometimes Refetoff syndrome) describes a rare syndrome in which the thyroid hormone levels are elevated but the thyroid stimulating hormone (TSH) level is not suppressed, or not completely suppressed as would be expected. The first report of the condition appeared in 1967.[1] Essentially this is decreased end organ responsiveness to thyroid hormones.[2] A new term "impaired sensitivity to thyroid hormone" has been suggested in March 2014 by Refetoff et al.[3]
https://en.wikipedia.org/wiki/Thyroid_hormone_resistance
From Dr Lowe:
n peripheral resistance to thyroid hormone, only the peripheral tissues are resistant. The pituitary tissue responds normally to a normal amount of thyroid hormone in the blood, and it decreases its TSH output when the blood levels signal that it should do so. Normal blood levels of thyroid hormone, then, properly suppress pituitary gland release of TSH, and keep the circulating TSH levels normal. What's important to realize in this scenario is that the feedback between the pituitary gland and the thyroid gland is normal, and both glands secrete normal amounts of their respective hormones. But the normal thyroid hormone levels are insufficient to override the partial resistance of tissues other than the pituitary--that is the peripheral tissues. As a result, metabolism in the peripheral tissues is subnormal. To speed peripheral tissue metabolism up to normal, the peripheral resistance patient must use large dosages of thyroid hormone. But the effect of these large dosages on the normally responsive pituitary tissue is suppression of the TSH. Thus, secretion of TSH, and its circulating level, are extremely low.
http://web.archive.org/web/20101030202007/http://drlowe.com/QandA/askdrlowe/resistnc.htm
Dr Lowe's reply makes sense to me, it seems like supplementing the thyroid can suppress my TSH to near zero and yet it does nothing. However, I have never tried the very high doses recommended in this situation.
On other forums it seems a few users have the same situation:
https://healthunlocked.com/thyroiduk/posts/130845602/no-response-to-high-dose-thyroxine-why
https://healthunlocked.com/thyroiduk/posts/131285373/high-dose-t3.-no-response.-thoughts
You'll see in the discussion one recommends to read Recovering with T3 from Paul Robinson.
A few more links to articles:
http://www.thyroidresistance.com/thyroid-resistance/