High doses of thiamine are completely safe
6.0Moderate
evidence
evidence
The Claim
Some people assume that because thiamine is a water-soluble vitamin, taking high doses poses no risk of harm or side effects.
Origin
This belief is rooted in the general perception that water-soluble vitamins are excreted easily and therefore cannot accumulate to toxic levels in the body.
What Science Says
While thiamine is indeed water-soluble and excess amounts are typically excreted, high doses can still cause adverse effects in some cases, such as allergic reactions or gastrointestinal issues. A review of vitamin safety profiles highlights that although high-dose toxicity is rare, it is not impossible, particularly when administered intravenously.
Verdict
Partially True