I will be delighted to provide updates as I continue with the repletion protocol, and Iḿ so glad that there may be others here who will look into this. For now, I will update with evidence that I started the B1 supplementation a bit too aggressively at the outset, including the highly bioavailable TTFD (one of the synthetic B1s) in the early weeks, before I should have done so, apparently. B1 is a strange and wonderful animal, it turns out. If we try to replete our blood levels and the small amounts we keep stored in cells too quickly, via higher doses or more bioavailable B1 sources, we can experience the ´paradoxical´ problem of our deficiency problems getting worse, rather than better, for a time. (In homeopathy, this would be called an ¨aggravation,¨ defined as a sign that a remedy could be correct, but was given either in too high a potency or too frequently). Paradoxical reactions are well known and understood in the Parkinsonś Disease community that relies on B1 repletion, btw. So my upper respiratory symptoms worsened/relapsed a day or so after I added TTFD to my thiamine HCl supplement, and so I TEMPORARILY discontinued all B1 supplementation in order to allow for a quieting period. (Some recommend suspension for as long as two weeks, in this scenario.) The amount and type of B1 that deficient patients will respond to varies wildly. Only trial and error will get one to the sweet spot in which there is a remission of deficiency symptoms and arrest of progression of illness. So my tentative revised approach is now to start back on an escalating dose of good old thiamine HCl (not mononitrate) to which I will again soon add increasing strengths of TTFD. It is always a good idea to pair any thiamine supplementation with a moderate-level B-complex, moreover. (The B vitamins work best as a group.) But again, the sweet spot for each of us, in terms of amounts and types of B1, is something we must apparently determine on our own. There are patients who get good results on just 100 mg or less of drugstore thiamine HCl, and others who need as much as 1500 mg of some combination of natural and synthetic B1 sources in order to get well. And like long COVID, getting to the sweet spot of better health can be a bit of a long journey. In any case, the only other useful info I can think of to add here is that I have come to realize that I should not shun Rx or OTC remedies that may get me through the day, if any helpful ones exist, as this helps greatly to sustain motivation to keep going in what can be a lengthy process including ups and downs. Since high anxiety came with my particular long COVID markers, I now palliate that with an herbal remedy that is also known for its anti-viral properties (fully expecting that ultimately, repleting my B1 will by itself eliminate my post-COVID anxiety problem., since B1 is famous for helping to control anxiety.) In addition, I make sure to try to be in some form of human company every day, if possible (not always easy or automatic). Iĺl close by sharing that a few days ago, I read a peer-reviewed study report that found (wait for it: . . . .) that it ¨seems¨ to be possible that the reason placebos work is that they activate patients´ ability to hope again. (Duh???) I have, many times, as an average human layperson, seen hope, alone, as highly effective in supporting patients on any course of treatment. The time has come for our doctors to stop being afraid of giving us what they still call ¨false hope.¨ To me, there is no such thing as false hope. Hope is hope, and recoveries that some consider miracles DO regularly happen. When we peel the surface back, we often see that those who recover and overcome tend to people who work at keeping hope and high expections alive.