Having to go off NDT after several years and back on levo only - how to explain it?

OK, so I went off NDT and back on T4 only a few weeks ago, after suffering bothersome symptoms for several months, such as profuse sweating (waking up every morning in a bed drenched in sweat), racing heart, high blood pressure (treated with perindopril 10 mg daily, GP wants to switch me to beta blockers if my heart rate won't come down from 95 bpm), nervousness/aggressiveness, increased sugar cravings and having clammy skin most of the time. I tried to adjust my NDT dose but ended up taking T4 only as any amount of NDT seemed to cause hyper symptoms.

During the years I spent on levo only (2000-2011, diagnosed with Hashi's in 2000), I was a notoriously poor converter. Back then, I did not know what I know now, but looking back at old labs I can see that my FT3 levels were barely midrange even on 200 mcg of levo daily (with FT4 at top of range). That was the reason I decided to see a so called Hertoghe doctor in Belgium who put me on NDT back in 2011.

Of course, during the years I took levo only, I had no idea about the importance of optimising vitamin and mineral levels to improve T4 to T3 conversion, so that may have been part of the problem.

I did great on NDT for years, taking as much as 6 grains daily with no ill effects whatsoever.

After being treated with high doses of steroids for autoimmune encephalitis in late 2018, I ended up with high cortisol levels x 4 (confirmed by Genova saliva stress test which also showed bottom range DHEA).

That explained why I had not been able to fall asleep until 3 am or to get a whole night's uninterrupted sleep.

After asking for advice here, I decided to try Adrenal Strength by MegaFood. It contains holy basil, ashwangdha, rhodiola rosea and L-serine, along with vits B, C and selenium.

Since I started it, I notice feeling less agitated and I can now fall asleep at night and sleep through the night.

But if it helped with some symptoms, such as increased agitation and poor sleep quality, others remained, the most bothersome being racing heart, profused sweating and sugar cravings that not even prescription drug Victoza could control.

I have been trying to find a link between high cortisol and thyroid hormone. Most articles talk about low cortisol (adrenal fatigue) and how that makes it impossible for thyroid hormone to enter the cells. But there are not as many articles about high cortisol and thyroid...the STTM talks about "pooling of T3" in people with high cortisol, but I am not sure how reliable that info is TBH.

Based on my latest labs, my hormone doctor raised my Oestrogel from two pumps a day to three, and told me I could go up to four if needed, and also told me to take 100 mg of Utrogestan every night instead of 200 mg ten days a month.

However, estrogen raises TBG (thyroid binding globulin), so it's common to feel more hypo when on HRT, not the other way around. My thyroid hormone needs seem to have decreased substantially even on higher doses of estrogen.

Although I am doing OK on T4 only for now (I notice the energy on levo only is quite different, no sudden jolts of energy like on NDT, but smoother energy levels lasting throughout the day), I have been trying to understand what is happening to me. I know it's normal for hormone needs to change throughout our lives, but in my case this change happened so suddenly, literally within a couple of months, and also in a very dramatic way. For a long time, I was convinced I had found the right drug for me (NDT), and that all I'd need to do would be to adjust the dosage according to symptoms. Now, it seems I cannot handle any amount of T3.

I have been working on correcting several vitamin and mineral deficiencies (vit D, vit B12, magnesium, zinc, iron, and folate using supplements recommended here along with chicken liver capsules), and that could possibly explain why I need less T3 (provided T4 to T3 conversion has improved as a result).

But I cannot help but wonder how common it is for someone to feel great on a given type of drug for years, then suddenly no longer being able to tolerate it?

My latest labs on 3 grains of NDT daily showed FT4 0.7 (0.7-1.5) and FT3 2.7 (1.7-3.2) so not overmedicated according to those results. Going lower than that would cause my FT4 levels to drop below range, and raising it would most likely push my FT3 levels over range.

I have been reading the book "Tired thyroid" by Barbara S. Lougheed, which claims that T4 is not merely a storage hormone but has a role of its own in the body. According to this theory, low or below range FT4 levels would cause symptoms regardless of FT3 levels. However, many people on NDT have low or below range FT4 levels and feel absolutely fine. Not to mention people on T3 only...!

This book also claims that taking too much T3 (and this does not necessarily mean having above range FT3 levels, just taking too much T3 relative to T4) causes insulin resistance which I have been diagnosed with. I connected it with the steroid treatment, but maybe the T3 in NDT made it worse. That could possibly explain why the problem did not go away after I weaned off the steroids after six weeks.

The book says that the T3/T4 ratio in NDT is unnatural for humans, and that taking NDT only risks leaving us FT4 deficient with excessive FT3 levels. The solution is to combine low doses of NDT with T4 to achieve what the author calls "human levels" as opposed to those found in pigs. However, she also says that when taking T3, the body decreases T4 to T3 conversion as less endogenous T3 is needed, and increases T4 to rT3 conversion. Even if rT3 is not as problematic as once thought, this would still mean less available T4, so I am not sure how adding T4 to NDT will raise FT4 levels. It would seem that any amount of T3 taken by mouth causes the body to increase T4 to rT3 conversion, so I am having trouble understanding that theory. But I was impressed to read how the author improved her health and achieved symptom-relief taking mostly T4 and a little NDT. If T4 only does not work out for me in the long run, I might try that approach rather than NDT only.

I know some members take NDT and T3, but would imagine some take NDT + T4? I would be interested in hearing about your experiences.

The interesting thing is that, while most of my symptoms are indicative of hyperthyroidism, I have noticed increased brain fog which is more of a hypo symptom, and wonder if this could be the result of low FT4 levels.

I know the T3/T4 ratio in NDT is not ideal for everyone; however, it suited me just fine for years, which tells me there has been a major shift in my hormone needs. I am now trying to figure out what could have caused this.

Any ideas?