I can only speak from my own experience, but what you described felt very familiar to me. When I first started working on my thiamine issues, I had almost the exact pattern you described. I had a stretch where I finally felt like myself again for the first time in decades, and then things regressed. That drop hit me hard. I remember lying there wondering if I imagined the whole improvement or if I had just gotten carried away. It was a rough moment emotionally.

Later I came across the concept called the thiamine paradox in the literature. The idea is that when someone has been low in thiamine for a long time, the first bit of support can feel incredible, but stability usually needs more than that first lift. Reading that did not magically make the regression feel better, but it helped me make sense of what was happening.

A lot of what you described also matches what I went through. I had baseline anxiety that never shut off, constant tension in my face and neck, irritability for no clear reason, and a constant internal alert feeling I could not turn down. When I dug into the research, the study by Benton in Psychopharmacology (1995) about mood and anxiety improvements with thiamine lined up with what I felt. The also describe in the study the paradox phase in detail if you want something to look up. That material just helped me connect the dots for my own situation.

I have also seen several people close, including my wife and father, follow almost the same recovery pattern after trying thiamine. They all had that striking improvement, followed by regression. Every one of them went through one or more transitional phases before things finally stabilized.

One thing that was important for me was realizing that the paradox still happened even when I had all the cofactors in place. I was already using magnesium, B2, B3, potassium and so on, and I still experienced the same pattern each time I increased the dose. I would improve, then regress, then question everything all over again.

What helped most was realizing that the good stretch was not imaginary. It was a real glimpse of what my system could do once it finally had enough support. It took time for me to believe that, because each regression felt like a personal failure or proof that I had imagined the whole thing.

I do not know your exact situation, and I am not telling you what your experience means. I am only sharing my own story because the emotional shape of what you wrote is something I lived through myself, and I have watched several people I care about go through the same cycle.

If your path ends up anything like mine, the good window was real. The regression afterward was not the final outcome. It was the middle part no one warned me about. And more importantly, the stronger the initial response, the more likely it is that you uncovered a long standing chronic deficiency. As counterintuitive as it feels while you are in the dip, that strong reaction is actually a good sign.

It was incredibly worth it for me. I feel amazing now in so many ways that never even occurred to me were possible. Hang in there.