The vitamin nobody checks you for.

Tell me if this sounds familiar.

You have a vague constellation of multiple symptoms that may include all, or some, of the things below:

…and many others.

Yet you go to the doctor, and he/she tells you that you are completely fine and that all labs are normal. Or you are given a diagnosis that doesn't really match up with the symptoms you are experiencing.

You are essentially a medical mystery, written off as a crazy hypochondriac, and sent on your way — while, likely, being aggressively pressured with anti-depressants or other anxiety medication.

This was my life for years.

Conventional medicine is highly advanced in many ways. It can take a patient who arrives at the Emergency Room after multiple gunshot wounds, a life-threatening heart attack, or a catastrophic car accident, and often save that patient's life.

The problem is when you do not fit cleanly into a box. If your brain MRI is normal, you can walk in a straight line in a neurological exam, and your electrolytes and blood work are not catastrophically abnormal, you are going to be put in the box marked "medical mystery" nearly 100% of the time.

As is often the case for people with chronic symptoms like fatigue, lightheadedness and POTS, dizziness, anxiety, or other vague symptoms that are difficult to diagnose, I essentially became my own doctor and researcher.

I was desperate to get better, and I tried so many different things that didn't improve my symptoms — supplements, therapy, breathwork, specialty doctors, rare and unconventional treatments, cryotherapy, the Nemechek Protocol, restrictive and extreme diets, going gluten free, sauna, IVs, IM injections, SSRIs, hypnosis. You name it, I have tried it.

Some things helped more than others. But I discovered one thing that was the true game changer.

However, you have almost certainly heard far more about vitamin B12, vitamin D and vitamin C than you have ever heard about vitamin B1.

There's a reason for that. And it starts with the disease that taught us vitamins existed at all.

This has happened before

In the 1800s, doctors were facing an illness they could not explain.

Patients arrived with symptoms that made no sense together. Burning and tingling in the feet. Racing hearts. Swelling. Breathlessness doing nothing. Confusion. Loss of balance. Some lost the ability to walk. Some died as their hearts failed — the acute form could kill a healthy young man in days.

And no two patients looked alike. One presented as a nerve problem, the next as a heart problem, the next as a psychiatric one.

Doctors hunted for an infection for decades. There wasn't one.

It was called beriberi, from a phrase meaning I cannot, I cannot — what sufferers said when asked to stand.

Every one of those people was missing the same single nutrient. Polished white rice had become cheap, and polishing strips out the part of the grain where thiamine lives. That was the whole answer.

Nerves, heart, brain, from one missing vitamin. Hold onto that.

Then medicine decided the story was over

Once you know a deficiency disease's cause, the fix is obvious — put the nutrient back. Flour enrichment began in the US in the 1940s, and beriberi went from a health crisis to a chapter heading.

That is where mainstream thinking on thiamine stopped.

Open a medical textbook today and thiamine deficiency is taught as something that happens to a short list of people: alcoholics, the severely malnourished, patients after bariatric surgery, severe morning sickness.

That list isn't wrong. The problem is what it does to a doctor's thinking when someone who isn't on it walks in. If you're not visibly malnourished and you don't drink heavily, thiamine never comes up. It isn't dismissed — it's never considered.

The assumption underneath is that your thiamine requirement is a fixed number, and that enrichment covers it.

It isn't, and it doesn't.

I tested mine. It came back normal.

I want to be clear that I did the obvious thing. Once I started reading about thiamine, I got my B1 tested.

Here is the actual result.

I was relieved, and I crossed it off the list. Whatever was wrong with me, it clearly wasn't this — the test said so. I went back to looking elsewhere for another few months.

Then I found out what that test actually measures.

The standard B1 test looks at the thiamine floating loose in your blood. That is a tiny fraction of the thiamine in your body, and what it mostly reflects is what you ate in the last day or two. The overwhelming majority of your thiamine isn't floating around in your bloodstream at all — it's inside your cells, in its active form, which is the only place it does anything.

I'll save you the rabbit hole I went down next: there is no better test you should go chasing. Don't spend months trying to get a specialist to order something exotic. The practical answer — and the one I eventually took — is far simpler than that, and it's what the rest of this guide is about.

That was the moment I stopped accepting "we ruled that out" as an answer.

Deficiency is a spectrum, and you're picturing the wrong end

Right about here you're probably thinking: fine, but I'm not dying of beriberi.

Correct. And that's the misunderstanding at the centre of all of this.

Beriberi is one end of a spectrum — the far end, where it's gone so deep and so long that you can't walk. That end is what doctors are taught, and so are the people who reach it: alcoholics, the severely malnourished, patients after stomach surgery.

But a nutrient your body burns through every hour doesn't work like a switch. There's an enormous middle, where you have thiamine but not enough for what your body is asking of it. You don't get a disease with a name. You get symptoms.

That middle is what the research calls functional thiamine deficiency. And here's the part that matters:

It happens with normal blood levels, on a normal diet, in people who don't drink.

Swallowing thiamine is not the same as using it. Your body has to convert it into an active form and get it inside your cells, and that machinery can run badly. When it does, you are short of thiamine exactly where it matters — while your blood test looks completely fine.

There's a name for one common version of this. Dr. Chandler Marrs, PhD, and Dr. Derrick Lonsdale, a Cleveland Clinic physician, call it high calorie malnutrition: modern food delivers plenty of calories and very little else, while the refined carbohydrate in it raises your thiamine demand — because thiamine is what your body uses to process carbohydrate in the first place. More demand, less supply, and nobody involved looks malnourished.

Why it looks like everything

Go back to that symptom list at the top — the one that made you keep reading.

It looks random. That's exactly why you get written off: no doctor can look at that collection and see one disease, so they conclude there isn't one.

It isn't random. It's a list of the tissues in your body that use the most energy.

Thiamine works at the gateway into your cells' energy production. When that step runs slowly, every cell makes energy less efficiently. Nothing is broken, nothing shows on a scan — everything is just running on less. So the expensive tissues complain first:

• Brain — 2% of your body weight, ~20% of your energy. Fog, anxiety, mood, memory.
• Autonomic nervous system — runs heart rate and blood pressure without a break. Lightheadedness, palpitations, POTS-shaped symptoms, flushing.
• Peripheral nerves — long and expensive to maintain. Tingling, burning, numbness.
• Gut — moves by constant nerve signalling. Bloating, slow digestion, new intolerances.
• Inner ear and eyes — high-demand sensory tissue. Balance, coordination, vision and hearing changes.

That's the great imitator problem. Thiamine doesn't have one presentation because it doesn't do one job — it shows up as whichever of your high-demand tissues gives out first. Which is why it looks like anxiety in one person, dysautonomia in the next, and IBS in a third, and why it gets missed by a system built to sort people into boxes.

If you already have a diagnosis

Thiamine doesn't respect diagnostic boundaries, because it isn't a disease. It's an input, and several different conditions can be short of it at once. Here is where the mechanism in this guide overlaps with names you may already have been given:

• POTS and dysautonomiaAutonomic function runs continuously and costs a great deal of energy. It's the system that shows strain earliest when cellular energy production drops.
• ME/CFS and long COVIDPost-exertional crashes are what an inefficient energy pathway produces under load — you spend capacity you can't replace.
• FibromyalgiaOne of the conditions with published case reports specifically on high-dose thiamine and fatigue.
• Peripheral neuropathyLong nerves are among the most expensive tissue in the body to maintain, and this is where the benfotiamine research is strongest.
• IBS, SIBO and refluxGut motility runs on constant nerve signalling, and signalling runs on energy. Nothing shows on a scope because it isn't structural.
• MigraineHigh-demand neural tissue with a low threshold for metabolic stress.
• Diabetes and blood sugar problemsHigh blood sugar measurably increases how much thiamine you lose through your kidneys.
• Anxiety that hasn't responded to treatmentA nervous system running short of energy generates alarm. Treating that as purely psychological works on the wrong layer.

None of this means thiamine treats any of those conditions, and I'm not going to pretend otherwise. It means that if you have one of them and nobody has ever looked at your thiamine, there's a mechanism worth understanding before you decide you've tried everything.

People who got their lives back

These are real people writing publicly, under their own names, about what happened to them. I didn't collect these and I don't know any of them. You can go and read every one of these accounts in full.

Every one of those four people was a medical mystery first.

I'll say the obvious thing rather than let you think I'm hiding it: individual stories are not proof, and thiamine does not do this for everybody. But these aren't four isolated accounts. Stories like these have been piling up for years, and they nearly all start the same way — with someone being told they were fine.

So how do you fix it?

Here's the part that surprised me most.

You don't fix it by eating better. If your problem were simply not enough thiamine in your food, a decent diet would have sorted it out years ago.

And you don't fix it with a normal supplement dose either. The RDA for thiamine is a little over one milligram. That number is the amount a healthy person with functioning machinery needs in order to not get beriberi.

It was never designed for someone whose machinery is the problem.

If the bottleneck is converting thiamine and getting it into your cells, you get past the bottleneck by putting far more pressure on it.

There's a real mechanism behind this. At ordinary doses, thiamine enters your body through a transport system that can only carry so much at a time — it saturates, and taking a bit more achieves nothing. But at high doses a second route opens up. Thiamine starts crossing into the body by simple diffusion, driven by nothing more than concentration.

In plain terms: you flood the system.

You take enough thiamine that a meaningful amount gets through regardless of how well the conversion machinery is working. That is the entire logic behind high-dose thiamine protocols, and it's what separates them from taking a B-complex and hoping.

That's what I did. Here's what happened.

What happened when I took it

I'm not a doctor and I'm not telling you what will happen to you. This is what happened to me.

That's the whole story, and it's the least useful part of this guide — because what you actually need is not my results. It's what it took to get them.

It is not as simple as buying a bottle

I want to be honest about this, because most people writing about thiamine are not: getting this right took me a long time, and there were stretches where I felt worse and genuinely thought about stopping.

Three things have to be true. Most people get one of them.

Get the ramp, the cofactors or the form wrong and you will conclude this does nothing — not because it does nothing, but because you never actually gave it a fair trial.

I worked all of this out the slow way, through months of ups and downs and a few false starts that set me back weeks. So I wrote the guide I wish someone had handed me at the beginning.

The full guide

Everything above is the why. The guide is the how — about 40 pages covering what this page deliberately doesn't:

• The titration schedule — what to start at, how much to increase, how often
• All four forms — how each behaves, and how to work out which suits you
• A dosing approach for each form — they are not interchangeable
• The cofactor balance — ratios, amounts, and the order to introduce them
• My exact protocol — what I take, doses, timing, monthly cost
• Practical details — the coffee interaction, food, missed doses
• What to expect, honestly — including where people notice nothing
• When to stop and when to see a doctor
• A one-page printable reference card
• Full references, so you can check every claim yourself

And it reads in one sitting

It took months to compile and it leaves nothing out — but it isn't a textbook, and it isn't padded to justify the price. Everything in it is there because you need it to do this properly, and nothing is in it to look thorough.

That mattered to me while I was writing it, because a fair number of people reading this have concentration that isn't what it used to be. I know what it's like to open something you badly need to understand and not be able to hold onto it. So it's written to be got through in an evening, not studied.

Everything in it is documented

I am not asking you to take my word for anything.

Every mechanism, every dose range and every claim about what the research shows is cited to the actual paper it came from — the controlled trials, the published case reports, the clinical literature on thiamine that has been quietly accumulating for a century. You can go and read the sources yourself, and I would rather you did.

And then there's the part the papers don't give you. Research tells you that high-dose thiamine works for some people. It does not tell you what to do when week two goes badly, what order to introduce things in, how fast to move, or how to tell a paradoxical reaction from a genuine problem. I learned that the hard way, on myself, over two years of trial and error — and every piece of it is in the guide.

Documented science you can verify, tested against real experience.

Why this costs $37 and not $3,000

I spent thousands of dollars trying to get better. Specialist appointments that went nowhere. Supplements that did nothing. Treatments, protocols, scans, programmes — a list I would genuinely rather not add up.

When you are desperate and nobody can tell you what's wrong, you become the perfect customer for anyone selling hope.

There is no shortage of people in this space willing to do exactly that.

So let me be clear about what I am not selling you. I'm not selling coaching. I'm not selling a $3,000 group programme with weekly calls and a private community. There's no membership and no "apply to work with me."

There is one thing, and this is it: a $37 PDF. Two years of research and personal trial and error, written down in the order I wish someone had handed it to me at the start.