Is Vitamin B1 (Thiamine) safe?
Pro Research Analysisby 
Searched over 200M research papers
Consensus Meter
Safety of Vitamin B1 (Thiamine)
Introduction to Thiamine Safety
Vitamin B1, also known as thiamine, is an essential nutrient that plays a critical role in carbohydrate metabolism and the proper functioning of the nervous system. Its safety profile is generally considered favorable, especially when used within recommended dosages. This article synthesizes current research on the safety of thiamine, highlighting its benefits and potential risks.
Thiamine Deficiency and Public Health
Thiamine deficiency is a significant public health issue, particularly in populations with poor nutritional intake or high alcohol consumption. Deficiency can lead to severe neurological and cardiac disorders, such as Wernicke-Korsakoff syndrome, which can be fatal if untreated. Thiamine supplementation has been shown to result in dramatic clinical improvements and is considered a safe and effective public health measure to improve thiamine status across various population groups.
Safety Profiles of Thiamine
General Safety and Efficacy
Thiamine is generally safe when taken in recommended amounts. It is essential for the proper functioning of the nervous system, and deficiencies can lead to conditions like peripheral neuropathy. While there are safety concerns associated with other B vitamins, such as B6 and B12, particularly at high doses, thiamine does not share these risks. The benefit-risk ratio of thiamine supplementation is considered advantageous, especially when dosing recommendations are followed and serum levels are monitored.
High-Dose Thiamine Therapy
High-dose thiamine therapy has been explored for various conditions, including overnutrition-induced hepatic steatosis. In animal studies, high doses of thiamine did not affect body weight or blood glucose levels but did increase plasma concentrations of non-esterified fatty acids, suggesting a shift in energy utilization from carbohydrates to fatty acids. This indicates that high-dose thiamine may have specific metabolic effects, particularly in liver fat reduction, without significant adverse effects.
Thiamine as an Insect Repellent
Despite historical claims, thiamine is not effective as an insect repellent. Controlled experiments have found no evidence supporting its use in this capacity. The continued promotion of thiamine as a repellent poses a risk, especially in regions with endemic mosquito-vectored diseases.
Thiamine and Cardiovascular Health
Thiamine deficiency has been linked to various cardiovascular disorders, including heart failure, myocardial infarction, and chronic vascular inflammation. Supplementation may help mitigate these conditions, although more research is needed to fully understand its impact on cardiovascular health.
Conclusion
Thiamine (Vitamin B1) is generally safe and beneficial, particularly in preventing and treating deficiencies that can lead to severe health issues. While high-dose thiamine therapy shows promise in specific metabolic conditions, it is essential to adhere to recommended dosages to avoid potential adverse effects. Thiamine's role as an insect repellent is unsupported by scientific evidence, and its promotion for this use should be discouraged. Overall, thiamine remains a vital nutrient with a favorable safety profile when used appropriately.
Sources and full results
Most relevant research papers on this topic