u/Apart-Development354

The issue I'm facing is that I have awful reactions to B vitamins. The best description for when I take them is I feel like my body is full of toxins and my blood is full of poison. It's a systemic feeling. I get headaches, nausea, but it does not feel gut related - I get zero digestive symptoms. It's this full body type sickness.

I'm absolutely great day 1, day 2, usually around day 4 I get sick. But the first few days I feel great - it helps my energy, mood, dysautonomia symptoms. I genuinely think I would benefit a lot from them. But then the sickness comes. I've tried pushing through but the longer I stay on them the worse it gets. It's like its worse the more I have in my system. Doesn't matter how little I take (took crumbs before) it always catches up to me.

I just found a folate deficiency so I genuinely do need it. Started 1.25 mg folic acid (prescribed 5mg.) Made it to day 4 then had to bail. Takes a few days to a week-ish for symptoms to pass, as though my body is processing something out.

Last year I tried a bunch of different ones. I'm okay on B2, bad on B1, B9 and B12. I'm pretty sure I've tried methylated and non-methylated versions of at least b12, maybe B9. But this current run is definitely folic acid as it's doctor prescription.

I've tried MCAS treatment with no benefit too.

I also have a bunch of chronic health issues - ME/CFS, Dysautonomia and chronic migraine. But none of these symptoms/reactions fit any of my normal symptom patterns. I do also get these same full-body toxin feeling eating healthier foods. If I stick to "safe" foods (white rice, chicken, pepper, cucumber) I'm okay, but as soon as I try to bring spinach, beans, brown rice, etc. in I get sick like this too. Not sure if it's related, but same symptoms.

I came across the term MTHFR when trying to figure this out. Does any of this ring a bell for anyone? Is it something to look into/any advice?

I'm folate deficient. But whenever I try to take certain B vitamins (so far B1, B9 and B12 - b2 seems okay?) I feel great for the first few days and feel some of the benefit - better energy, clarity etc. - and then by day 4 the same set of symptoms stack up. Nausea, cracking headache and a very specific and awful systemic feeling that feels as though I'm being poisoned and my blood is full of toxins. It literally feels like my body cannot process something and is full of toxicity.

The same thing happens with "healthy" foods. I'm okay within a small window of food - white rice, chicken, pepper, cucumber and a small rotation of other foods. But if I were to go full range and healthy vibe - brown rice, broccoli, beans, etc. I would get the same issue - okay in small doses, but as soon as it increases in my system the same symptoms kick in.

I'm diagnosed with ME/CFS, dysautonomia and chronic migraines. I'm well aware that ME causes intolerance to meds and supplements, but these symptoms feel separate to all of those. These aren't my PEM symptoms. They're different to my migraine symptoms (which are usually more neurological.) And I'm wondering if there is a separate underlying issue beneath all of this. I just don't understand why my body would react badly to folic acid if I'm folate deficient (I was prescribed 5mg but started at 1.25. i've tried much smaller doses last year - crumbs - and it always builds up over the days. I tried pushing through for weeks last year and it just got progressively worse.) I've also tried MCAS treatments with no benefit, except this same reaction from ketotifen. And kombucha, which is obviously v high in histamine, helps me feel better.

I'm wondering if this is a red flag for another condition. Are there any conditions that can make your body react badly to B vitamins?! Is there something that can build up in your blood, or a condition that makes it so your body cannot tolerate or keep up with it the longer/more you take? I don't understand!

I've tried MCAS meds - no benefit, except ketotifen making this reaction worse. And don't notice adverse reaction to histamine foods particularly (kombucha actually helps.)

We just found overt hypothyroidism finally after it hanging around TSH 4. With other meds and supplements I have to titrate super carefully. I usually do 1/4-1/2 a dose a couple days a week and then build it up over weeks. Idk whether to do that with Levo because it’s a direct hormone my body makes and I obviously need it. I got prescribed 25mcg anyway so it’s low. But should I still titrate? My doc knows nothing about ME

Has anyone noticed SSRIs improving their symptoms? I came off fluoxetine (/prozac) last year and since then (to the month) my symptoms have gotten significantly worse - even tho my daily step count has improved?

TL;DR - For years my dysautonomia symptoms were posture related. Once I sat down, I was fine. For the last year, my ANS loses total control above a certain threshold - once it does, nothing fixes it for hours/days.

Before August/September 2025, most of my symptoms were posture related. I..e I'd stand up and get brain fog and tired and have to sit down. Mostly, it felt like fatigue and a bit of dizziness/lightheadedness and then I'd sit down and feel better (like woah that was a lot, but yey there goes the oxygen to my brain again. Now I'll rest until I have some energy again.) It was draining AF, but situational based.

Since August 2025 that's changed dramatically. Now, it feels like I have a very firm limit in what I can do - both at one time and cumulatively. If I overdo it, i.e. jog for a second or walk carrying something. OR do to much in across the day, it triggers a flare. I feel like I've totally lost control of my ANS. I feel out of control, heart palpitations, breathlessness, adrenaline surges etc. and really shakey. I'm housebound and I can't leave mainly because sitting in the car causes my to lose control like this. I can't cook, showering puts me right up to the edge. I also have for the first time nocturnal symptoms - I flare most nights after 11pm and often have to take sleeping tablets to get any sleep/stop the cascade that starts. This started September 2025 and was so bad I nearly called a ambulance.

For context, I have both M.E. and dysautonomia. Since 2006 I've been ill (likely with just dysautonomia) but been able to live a normal life just a bit miserable and very tired all the time, with a myriad of classic pots/dysautonomia symptoms. My function level stayed the same for years until 2019, when I crashed and developed M.E. At that point my function was able to deteriorate for the first time (and boy did it.)

I finally woke up this year, realised I'd been boom/busting, and started pacing properly in Dec/Jan 2026. Since then, for the first time my daily step count is increasing. For the first time I feel like i'm nailing it and might recover. July 2025 (my lowest) I was at 545 daily steps, Aug 2025 842, sept 1284. I'm now at 2600 average. It's increased really slowly.

But the state of my dysautonomia isn't improving. I still flare easily. Despite my step count being what it was prior to this dysautonomia shift (more, in fact), I'm still in this new reality of dysautonomia. I don't understand what changed?

I started medication in April 2026. Bisoprolol, Pyridistigmine, Midodrine. Prior to that I was bedbound and just standing up would trigger a flare. It helped, but I'm still very disabled.

My few theories are:

1. I overdid it stupidly in April, May and June of 2025 causing a big crash. Has my physiology just changed since then, maybe I crossed a threshold in the diseases.
2. Did the April-June crash cause deconditioning that I just haven't gotten back as I've been pacing since (so even if across the day I'm doing more, I'm doing less at any one time.)
3. I came off fluoxetine (an SSRI) in August 2025. I'd been on it since 2021. Could this have been subtly helping my ANS without me realising, and taking it away removed a crutch by accident?

I'd be confused if it were 1 or 2 because surely it would have hit worse during July when I was at my lowest in terms of PEM etc. I also am pretty sure I'm doing so much more overall that I've probably got some of the conditioning back by now, but symptoms aren't better at all. I just don't know enough to know if 3 is even possible.

Any help would be amazing, I'm totally lost and so frustrated that I thought I had it all figured out this year and this came out of nowhere.