Thiamine HCl · Benfotiamine · Vitamin B1
Critical B-vitamin GLP-1 users deplete through reduced food intake — Wernicke's risk at extremes.
FDA
Approved
WADA
Not Listed
HALF-LIFE
~4h (HCl form); longer (benfotiamine)
ROUTE
Oral
SCHEDULE
Daily
In Plain English
Critical B-vitamin GLP-1 users deplete through reduced food intake — Wernicke's risk at extremes.
Status & Legality
NATTY?
No Test ExistsNo established test exists for this compound.
FDA
ApprovedFDA approved for human use.
WADA
Not ListedNot currently on WADA prohibited list.
COMPOUNDING
Rx AvailableAvailable at licensed pharmacies with prescription.
PRESCRIBED
By prescriptionPhysicians can prescribe this compound legally.
ROUTE
OralAdministration via oral.
Thiamine deficiency prevention
Glucose metabolism
Neuropathy prevention
GLP-1 essential adjunct
Thiamine is required for pyruvate dehydrogenase — the enzyme that gates glucose entry into the Krebs cycle. GLP-1 users are at documented risk of thiamine deficiency from dramatically reduced food intake; at extremes this progresses to Wernicke's encephalopathy. Benfotiamine (fat-soluble thiamine) achieves significantly higher tissue concentrations than standard thiamine HCl and is preferred for neurological protection.
Essentially none at normal oral doses
Yellow urine (benign, water-soluble vitamin)
No known toxicity ceiling for oral forms
Rare allergic reaction (IV form only)
Relying on a standard multivitamin — most contain thiamine HCl in amounts adequate for non-deficient, non-restricting individuals; GLP-1 users need targeted supplementation
Not choosing benfotiamine when neurological protection is the goal — benfotiamine achieves 5× higher tissue concentrations in peripheral nerves vs standard thiamine HCl
Waiting until symptoms develop — Wernicke's encephalopathy prevention requires proactive supplementation before deficiency occurs, not treatment after
Loop diuretics (furosemide) — significantly increase thiamine excretion; mandatory supplementation when on chronic loop diuretics
Alcohol — alcohol dramatically depletes thiamine via multiple mechanisms; the basis for Wernicke's in alcohol-use disorder
Generally no clinically significant drug interactions with standard oral doses
Thiamine is the most underrated GLP-1 safety supplement. The documented cases of Wernicke's encephalopathy in bariatric surgery patients apply directly to GLP-1 users achieving similar caloric restriction pharmacologically. 100 mg benfotiamine daily is inexpensive protection that most GLP-1 prescribers fail to mention. Start on day one, not after symptoms appear.
Stats
Sources & Studies
Lonsdale D., J Complement Integr Med, 2006