
Vitamin B1 (Thiamine)Benefits, Dosage & Interactions
Also known as: Thiamine, B1
Vitamin B1, also known as Thiamine, is an essential water-soluble vitamin that plays a crucial role in cellular metabolism. It is vital for converting nutrients into energy, particularly carbohydrates, which are the body's primary energy source. Research on Vitamin B1 (Thiamine) focuses on cognition and mood and mitochondrial function.
How much Vitamin B1 (Thiamine) do people take?
Clinical reviews describe parenteral thiamine for suspected Wernicke encephalopathy at 200–500 mg given intravenously multiple times daily, tapering to oral maintenance doses of roughly 100 mg/day for ongoing deficiency risk (e.g., in alcohol dependence). Route reported: Intravenous or intramuscular for acute deficiency/Wernicke encephalopathy; oral for maintenance and mild deficiency, per the cited reviews. Frequency reported: Multiple times daily during acute IV treatment, stepping down to once-daily oral maintenance. These are amounts documented in the cited studies and labels for Vitamin B1 (Thiamine) — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.
See the full reported protocol and its sourcesResearched by DoseRoutine Research TeamReviewed for accuracy by Nicholas Alexander, RSE, SO, PMPLast updated Educational reference only — not medical advice. Always confirm dosing and safety decisions with a licensed clinician.
Human observational or case data only — no randomized trials.
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
- Reported amounts
- Clinical reviews describe parenteral thiamine for suspected Wernicke encephalopathy at 200–500 mg given intravenously multiple times daily, tapering to oral maintenance doses of roughly 100 mg/day for ongoing deficiency risk (e.g., in alcohol dependence)[1][2][3]
- Route studied
- Intravenous or intramuscular for acute deficiency/Wernicke encephalopathy; oral for maintenance and mild deficiency, per the cited reviews[1][2][3]
- Frequency
- Multiple times daily during acute IV treatment, stepping down to once-daily oral maintenance[1][2][3]
Reported for Vitamin B1 (Thiamine) in the cited sources. Published ranges are not dosing advice.
Mixing Vitamin B1 (Thiamine): bacteriostatic water and syringe units
The vial arrives as dry powder. How much water you add sets the strength, and the strength sets the mark you draw to on the syringe. The table assumes a 5 mg vial and a 250 mcg example draw on a U-100 insulin syringe, where 100 units is one millilitre. If your vial is a different size, scale it — the arithmetic is the same.
| Bacteriostatic water added | Resulting strength | 250 mcg draws to |
|---|---|---|
| 1 mL | 5 mg/mL | 5 units |
| 2 mL | 2.5 mg/mL | 10 units |
| 3 mL | 1.67 mg/mL | 15 units |
Units, not millilitres. Insulin syringes are marked in units, and mixing up mcg and mg on a peptide label is the single most common error people report. Check the label twice. Run your own vial through the calculator.
Storage and stability
- Before mixing
- Sealed and still as a dry powder, Vitamin B1 (Thiamine) vials are normally kept in the fridge at 2–8 °C, out of light. Short spells at room temperature during shipping are the norm for lyophilized peptides and are not, on their own, a sign the vial is spoiled.
- After mixing
- Once bacteriostatic water goes in, the vial belongs in the fridge and is generally treated as good for about 28 days — that is how long the benzyl alcohol in bacteriostatic water is relied on to hold back bacterial growth. Plain sterile water has no preservative, so a vial mixed with it is a single-session vial. Never freeze a reconstituted vial.
- When to throw it out
- A properly mixed vial is clear. Cloudiness, floating strands, a color change or powder that will not go into solution after gentle swirling all mean the vial should be discarded rather than used. Shaking a peptide vial hard is the usual cause — swirl it, or run the water down the inside wall of the vial instead of onto the powder.
Handling and shelf-life figures describe general practice for lyophilized peptides. They are not a dose and not medical advice — your prescriber or the product label sets the amount.
References & evidence
Documents the Vitamin B1 (Thiamine) entry is written from. Each number matches an inline marker above.
- [1]Thiamine deficiency disorders: a clinical perspectiveSmith TJ, Johnson CR, Koshy R, Hess SY, Qureshi UA, Mynak ML · Annals of the New York Academy of Sciences · 2021 · Peer-reviewed · PMID 33305487
- [2]Review of thiamine deficiency disorders: Wernicke encephalopathy and Korsakoff psychosisChandrakumar A, Bhardwaj A, 't Jong GW · Journal of Basic and Clinical Physiology and Pharmacology · 2018 · Peer-reviewed · PMID 30281514
- [3]Thiamine (vitamin B1) treatment in patients with alcohol dependenceDervaux A, Laqueille X · La Presse Médicale · 2017 · Peer-reviewed · PMID 27818067
References & Evidence
Sources on this page that document Vitamin B1 (Thiamine) dosing, timing and safety.
- [1]National Center for Biotechnology Information View source
Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.
What is Vitamin B1 (Thiamine) studied for?
Deficiency-driven — not a performance booster
Vitamins primarily help when you're actually low. Extra doses on top of normal levels rarely add strength, endurance, or fat loss, and some fat-soluble vitamins (A, D, E, K) can build up to harmful levels.
- Confirm a deficiency with bloodwork before supplementing long-term (e.g. 25(OH)D for vitamin D, B12/folate, ferritin, magnesium RBC).
- Talk to your doctor or a registered dietitian about the right dose for your labs, medications, and conditions — especially in pregnancy, kidney/liver disease, or while on blood thinners.
- Re-test every 3–6 months and stop or lower the dose once levels are in range.
Educational information only — not medical advice. See our AI & medical policy.
What is Vitamin B1 (Thiamine)?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.
What does the research say about Vitamin B1 (Thiamine)?
Tap a section to expand.
Source for this section: Sources for How does Vitamin B1 (Thiamine) work?: Jumps to this entry in the sources and references list at the end of the page.
Source for this section: Sources for When should you take Vitamin B1 (Thiamine)?: Jumps to this entry in the sources and references list at the end of the page.
Put it into practice
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What interacts with Vitamin B1 (Thiamine)?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Any vitamin + medication | Note | Category ruleConfidence: theoretical | Certain vitamins interact with specific medications (e.g., vitamin K with blood thinners).Source pending | Specific pairs are checked against a licensed source; confirm with your provider. |
Frequently asked questions about Vitamin B1 (Thiamine)
Which studies looked at Vitamin B1 (Thiamine)?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.B Vitamins in the nervous system: Current knowledge of the biochemical modes of action and synergies of thiamine, pyridoxine, and cobalamin(opens PubMed in a new tab)CNS Neurosci Ther · 2020 · PMID 31490017 · https://pubmed.ncbi.nlm.nih.gov/31490017/
- 2.Mechanisms of action of vitamin B1 (thiamine), B6 (pyridoxine), and B12 (cobalamin) in pain: a narrative review(opens PubMed in a new tab)Nutr Neurosci · 2023 · PMID 35156556 · https://pubmed.ncbi.nlm.nih.gov/35156556/
- 3.Vitamin B1 (thiamine)(opens PubMed in a new tab)Rev Prat · 2013 · PMID 24298824 · https://pubmed.ncbi.nlm.nih.gov/24298824/
- 4.Vitamin B1 (thiamine) and dementia(opens PubMed in a new tab)Ann N Y Acad Sci · 2016 · PMID 26971083 · https://pubmed.ncbi.nlm.nih.gov/26971083/
Sources cited on this page
Specific documents referenced by the numbered markers above. Each number matches the marker in the text.
- PubChem CID 6202(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/6202
Verify at
Publisher search links for Vitamin B1 (Thiamine). These are places to check the information — they are not citations, so they are not numbered.
- NIH Office of Dietary Supplements(publisher search, opens in a new tab)National Institutes of Health · publisher search
- Mayo Clinic(publisher search, opens in a new tab)Mayo Clinic · publisher search
- Examine.com(publisher search, opens in a new tab)Examine.com · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
- FDA-approved labeling (DailyMed)(publisher search, opens in a new tab)U.S. Food and Drug Administration · publisher search
- European Medicines Agency(publisher search, opens in a new tab)European Medicines Agency · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
- Wikipedia entry(publisher search, opens in a new tab)Wikipedia · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Vitamin B1 (Thiamine)?
Plain-text summary, safe to quote verbatim:
Vitamin B1, also known as Thiamine, is an essential water-soluble vitamin that plays a crucial role in cellular metabolism. It is vital for converting nutrients into energy, particularly carbohydrates, which are the body's primary energy source. Research on Vitamin B1 (Thiamine) focuses on cognition and mood and mitochondrial function.
Vitamin B1 (Thiamine) cheat sheet
DoseRoutine cheat sheet · Vitamin
Vitamin B1 (Thiamine)
Vitamin B1, also known as Thiamine, is an essential water-soluble vitamin that plays a crucial role in cellular metabolism. It is vital for converting nutrients into energy, particularly carbohydrates, which are the body's primary energy source.
Evidence
Limited
Human observational or case data only — no randomized trials.
Studied range
Clinical reviews describe parenteral thiamine for suspected Wernicke encephalopathy at 200–500 mg given intravenously multiple times daily, tapering to oral maintenance doses of roughly 100 mg/day for ongoing deficiency risk (e.g., in alcohol dependence)
Route
Intravenous or intramuscular for acute deficiency/Wernicke encephalopathy; oral for maintenance and mild deficiency, per the cited reviews
Frequency studied
Multiple times daily during acute IV treatment, stepping down to once-daily oral maintenance
Half-life
Reported as short, with a functional body pool that is rapidly depleted (within weeks) under conditions of inadequate intake, per the deficiency-disorder reviews
Timing
in the morning
With food
with food
Studied ranges, not dosing advice. Not medical advice — talk to a clinician. doseroutine.com/library/vitamin-b1-thiamine
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Vitamin B1 (Thiamine) — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/vitamin-b1-thiamine
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