Vitamin B1 (Thiamine)
An essential B vitamin required for carbohydrate metabolism and nerve function — a cofactor in converting glucose into usable energy.
Deficiency causes fatigue, neuropathy and cardiac problems. Notably common in heavy alcohol users, people on diuretics, after bariatric surgery, and in poorly controlled diabetes — and it's routinely missed.
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Order this test — 10% off → Browse all 102 markers →What Vitamin B1 (Thiamine) is usually tested alongside
On its own, one marker is a data point. These panels include Vitamin B1 (Thiamine) plus the markers that make it interpretable — each names every test, why it is on the list, and loads the whole set into your cart in one click at 10% off.
includes this + 10 more markers — Restrictive diet, plant-based, post-bariatric, on a GLP-1, heavy training load, or you just want to stop guessing which supplements you actually need.
Would you feel it? Symptoms Vitamin B1 (Thiamine) helps explain
People rarely search for a marker — they search for how they feel. These are the complaints where this marker is worth checking, and whether it is a first-line test or a follow-up once the obvious causes are ruled out.
Why your Vitamin B1 (Thiamine) might be wrong
Most abnormal results are interference, not disease. These are the things that measurably move this specific marker — check them before you change anything. Each one says whether the number is wrong and should be repeated, badly timed and should be redrawn, or real with a cause worth explaining.
Thiamine degrades on light exposure and needs prompt, protected processing.
A low result from a mishandled sample is common. Whole-blood thiamine diphosphate is the better measure.
Chronic alcohol impairs thiamine absorption and storage, and loop diuretics force urinary loss — together the commonest causes of deficiency in the developed world.
Confusion, unsteadiness or eye movement problems with heavy alcohol use is a medical emergency — thiamine is given first, not after the test.
What Vitamin B1 (Thiamine) means in combination
A single marker tells you a little. Combinations tell you the story — these are the named patterns this marker takes part in, and what each one points at.
That is a malabsorption pattern, not a diet pattern. Coeliac disease, atrophic gastritis, H. pylori, pancreatic insufficiency and inflammatory bowel disease all present this way, and correcting the individual nutrients without finding the cause is a treadmill.
Investigate why absorption is failing rather than supplementing indefinitely. Coeliac serology must be done before removing gluten. Any neurological symptom with low B12 or copper needs urgent attention.
What to test next
Markers rarely answer alone. These are the ones that put Vitamin B1 (Thiamine) in context — each with its own full breakdown.
Frequently asked questions
70–180 nmol/L (whole blood) Ranges vary by laboratory and assay — always compare to the range printed on your own report.
Optimal ranges, root causes and the full correction protocol are available inside Coach Cam's Peptide Academy.
See the full breakdown inside the Academy.
See the full breakdown inside the Academy.
You can order Vitamin B1 (Thiamine) directly through Marek Diagnostics without a doctor's visit — drawn at any Quest Diagnostics location in the US. Code CAMERON applies 10% off automatically.