Vitamin B1 (Thiamine) safety profile
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Vitamin B1 (Thiamine) Safety Profile in Clinical and Supplement Use
General Safety and Adverse Reactions of Thiamine (Vitamin B1)
Thiamine (vitamin B1) is widely recognized as a safe, essential water-soluble vitamin with minimal safety concerns for most people. Serious adverse reactions are rare, especially when thiamine is administered orally or as part of a balanced diet. However, rare cases of anaphylactic shock, cardiac arrest, and injection site reactions have been reported with parenteral (injected) thiamine, particularly at high doses or with intravenous administration .
A study evaluating 500 mg intravenous push thiamine in adult patients found no cases of anaphylaxis among 463 doses. Only 0.86% of doses resulted in low-grade injection site reactions, all of which were mild and resolved without serious consequences .
Safety in Animal and Feed Additive Use
Thiamine hydrochloride and thiamine mononitrate, common forms of vitamin B1 used in animal feed, are considered safe for all animal species, consumers, and the environment. However, these compounds can act as skin and respiratory sensitizers, and thiamine hydrochloride is an eye irritant. Both forms are also considered skin irritants, so care should be taken to avoid direct contact during handling 34.
Thiamine Derivatives and Long-Term Supplementation
Thiamine tetrahydrofurfuryl disulfide (TTFD), a derivative of thiamine with higher bioavailability, has been studied for its safety in long-term supplementation. Animal studies show that daily administration of TTFD for over six weeks did not result in significant toxicity or adverse effects, supporting its safety for extended use at recommended doses .
Safety in Human Supplementation and High-Dose Use
For human supplementation, thiamine is generally safe when used as directed. There are no significant reports of neurotoxicity or other serious side effects associated with thiamine, even at higher doses, as long as dosing recommendations are followed and serum levels are monitored. This is in contrast to other B vitamins, such as B6, where high doses over long periods can cause neurological side effects .
Conclusion
Vitamin B1 (thiamine) has a strong safety profile for both clinical and supplemental use. Serious adverse reactions are extremely rare, and mild side effects such as injection site reactions or skin irritation may occur in specific circumstances, particularly with injectable or feed additive forms. Thiamine derivatives like TTFD also appear safe for long-term use at recommended doses. Overall, thiamine is considered safe for most populations when used appropriately 12345.
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