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Vitamin B1

What does the research say about Vitamin B1?

2 health outcomes synthesised

Vitamin B1 (thiamine) has been researched for 2 health outcomes, with the strongest evidence area being reduced mortality risk in critically ill patients, based on 3 studies. Doses of 50-100 mg/day have been examined in clinical populations, including patients with heart failure and those in intensive care.

Strongest evidence: The available evidence for both researched outcomes—reduced mortality risk and improved left ventricular ejection fraction—is rated as very low strength, with no outcomes reaching high or moderate levels of certainty.

Mixed or weaker evidence: For reduced mortality risk, all 3 studies reported neutral small-sized effects, none reaching statistical significance. For improved left ventricular ejection fraction, 1 of 3 studies found a beneficial small-sized effect, while 2 found neutral effects; the single positive finding came from a multi-ingredient supplement, making thiamine’s independent role unclear.

Effective dose patterns: When reported, studies on left ventricular ejection fraction used doses of 50–100 mg/day. No consistent effective dose was identified for mortality outcomes, as doses were not consistently reported.

Population insights: Research focused on critically ill patients (e.g., sepsis, septic shock) for mortality, and on patients with heart failure, children on diuretics, and cardiac surgery patients for ejection fraction. Results in these clinical populations remain preliminary.

Notable caveats: Across both syntheses, the evidence base is small (only 3 studies each), none of the studies reached statistical significance for mortality, and the beneficial ejection fraction finding cannot be attributed solely to vitamin B1. Many studies combined thiamine with other agents, and study durations (1–28 days) were likely too short for assessing cardiac remodeling.

Frequently asked

  • What is Vitamin B1 good for according to research?
    Research has investigated vitamin B1 (thiamine) for two primary outcomes: reducing mortality risk in critically ill patients and improving left ventricular ejection fraction in heart failure and cardiac populations. However, the evidence is very low strength, with mostly neutral results and no statistically significant benefits clearly attributed to thiamine alone.
  • What dose of Vitamin B1 is typically used in studies?
    For studies examining left ventricular ejection fraction, doses of 50–100 mg/day were commonly used. For mortality studies, doses were not consistently reported, and thiamine was often administered intravenously in clinical settings.
  • Who benefits most from Vitamin B1?
    Research has focused on specific clinical populations, including critically ill adults with sepsis or septic shock for mortality outcomes, and patients with heart failure, children on diuretics, and cardiac surgery patients for ejection fraction. No consistent subgroup has shown clear benefit, as findings were predominantly neutral.
  • Are there caveats or limitations in the research on Vitamin B1?
    Yes, major limitations include the small number of studies (only 3 per outcome), lack of statistical significance across mortality studies, and the use of multi-ingredient supplements that prevent isolating thiamine’s effects. Study durations were also short (1–28 days), which may be insufficient for outcomes like cardiac remodeling.
  • Does Vitamin B1 help reduce mortality risk?
    Across 3 studies, all reported neutral small-sized effects on reducing mortality risk in critically ill patients, and none reached statistical significance. The evidence is very low strength and considered preliminary.
  • Does Vitamin B1 improve left ventricular ejection fraction?
    Of 3 studies, only 1 reported a beneficial small-sized effect, and that finding came from a multi-ingredient supplement. Two studies were neutral, and the overall evidence is very low strength, making it unclear if vitamin B1 alone provides any benefit.

Most-studied combinations with Vitamin B1

most supplement research is combination research
Also studied with:Vitamin B2 (4), Vitamin B6 (4), Vitamin B9 (2), Vitamin B12 (6), Vitamin E (3), Vitamin C (7)
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