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Vitamin B1

Vitamin B1

Best for

Feel less pain

Promising early signal 300–600 mg/day 12–52 weeks 1 meta-analysis, n=203

Vitamin B1 shows a promising early signal for spending more time free from pain, but evidence remains limited and inconclusive across its broader range of health outcomes.

Median effective dose, most-studied outcomes

Full protocol, 4 outcomes

Risk, worst reported severity

  • urticaria moderate
  • bronchial asthma moderate
  • metformin major
  • phenformin major
All 18 events and interactions

What vitamin b1 actually does

Outcome Effect Evidence Dose Time Rank
Worth watching 1
Feel less pain Promising early signal Pain relief can make it easier to move, rest, focus, and get through the day.
moderate 		1 meta-analysis 3 papers · n=203 300–600 mg 12–52 wk —
Early research 2
Ease neuropathy symptoms Faint early signal Neuropathy can cause pain, numbness, tingling, weakness, and changes in sensation.
small 		2 RCTs 2 papers · n=51 300–600 mg 52 wk #6 /12
Reduce glycation damage in diabetes Not enough research Glycation damage happens when sugar attaches to proteins and can build up when blood sugar stays high.
trivial 		1 RCT 1 papers · n=82 900 mg 12 wk —

Effect tiers come from native-unit MCID where available, Cohen's d otherwise.

Protocol

Dose, timing & forms

How much

The high-dose research here focuses on pain and nerve-related outcomes, not everyday nutrition. Trials have examined 600 mg/day for pain or peripheral nerve signaling, while a small pain report used high-dose thiamine and found an encouraging but preliminary signal. 23 Research has also tested up to 900 mg/day for glycation-related protein damage, yet that result did not show a meaningful benefit. These are research protocols, not standard nutrition guidance. 1

When and how long

Use the schedule used in the specific product study, since the evidence does not establish one best time of day for high-dose B1. The pain and nerve protocols involved consistent daily use for many weeks, rather than taking it only when symptoms flare. 23 If a high dose causes nausea, taking it with food is a practical option, but that approach has not been tested as a way to improve results. 1

Forms & standardisation

Check whether a label lists plain thiamine or a derivative such as benfotiamine. The peripheral nerve trial cited here used benfotiamine, so its findings do not automatically apply to every thiamine product. 3 High-dose products are very different from a basic multivitamin, and a larger dose does not establish a larger benefit. 1

Studied range, by outcome

Outcome Studied range Median effective Duration Evidence
Feel less intense pain 600 mg — 52 wk 2 papers
Reduce glycation-related protein damage 900 mg — 12 wk 1 paper
Improve peripheral nerve signaling 600 mg — 52 wk 1 paper
Have less fatigue 600–1,800 mg — 4 wk 1 paper

Adverse events and drug interactions

Safety events

urticaria moderate
bronchial asthma moderate
nausea mild
alanine aminotransferase increased mild
urinary white blood cell positive mild
urinary red blood cell positive mild
proteinuria mild
glomerular filtration rate decreased mild

Drug interactions

metformin major decreases concentration
phenformin major decreases concentration
fedratinib major decreases concentration
amprolium major decreases concentration
asparaginase major decreases effect
cisplatin major decreases effect
oxaliplatin major decreases effect
chloroquine moderate decreases concentration
verapamil moderate decreases concentration
famotidine moderate decreases concentration
Buy well

Recommended Vitamin B1 products

Real products that dose Vitamin B1 where the research does, in a clean formulation, from brands we've audited. We only list ones we'd stand behind.

Chosen for adequate Vitamin B1 dosing vs. the studied range, a clean formulation (grade A–C), and independent brand-quality audits. Not sponsored.

In context

What this is and how it works

  • Three studies (n=203) reported more time free from pain with Vitamin B1 2.
  • Twenty-two papers reviewed here span 55 outcomes, including pain and peripheral nerve symptoms.
  • Evidence mainly concerns high-dose forms and remains early across varied populations and conditions.

Vitamin B1, also called thiamine, is an essential water-soluble vitamin. You get it from foods such as pork, legumes, fortified grains, nuts, and seeds, and your body stores only limited amounts. 1

Thiamine helps enzymes feed carbohydrate fragments into the cell's energy-making machinery, like handing cut firewood into a furnace instead of leaving it piled beside it. It also supports pathways that maintain nerve function, which explains why researchers have tested thiamine derivatives in people with peripheral nerve symptoms. 13

Bottom line

Vitamin B1 matters for basic energy metabolism, especially when dietary intake or absorption is poor. High-dose use for pain and peripheral nerve symptoms is worth watching, but the findings are early and inconclusive, so it is not a stand-alone answer for ongoing pain. 123 Avoid self-directed high-dose use if you take medicines that reduce thiamine levels or have had an allergic reaction to thiamine products.

Frequently asked

Common questions

What does vitamin B1 do in the body?

Vitamin B1, also called thiamine, helps enzymes turn carbohydrates into usable cellular fuel. It also supports chemical signals that help nerves communicate. 1

Can high-dose vitamin B1 help pain?

A few early studies report less pain with high-dose thiamine, but the evidence remains too limited to treat it as a reliable pain strategy. The most visible signal comes from a small fibromyalgia report, not a large definitive trial. 2

Is thiamine the same as benfotiamine?

No. Benfotiamine is a fat-soluble thiamine derivative designed to raise thiamine-related compounds in the body. Nerve-symptom research often uses benfotiamine rather than standard thiamine. 3

Sources

Sources

  1. 1. Thiamin Fact Sheet for Health Professionals (2024)
  2. 2. High-dose thiamine improves the symptoms of fibromyalgia (2013) ↑
  3. 3. Benfotiamine in diabetic polyneuropathy (BENDIP): Results of a randomised, double blind, placebo-controlled clinical study (2005) ↑

Generated August 27, 2026

Related

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