Vitamins contain essential micronutrients that are needed for normal cell function, growth, and development
However, when very high oral doses are taken, approximately 1% can be absorbed through passive diffusion, independent of intrinsic factor, which explains how mega-doses can still raise serum levels
This is important because rapid IV administration can lead to sudden shifts in electrolytes particularly potassium which may result in hypokalemia and, in severe cases, cardiac complications
When levels drop too low, the effects can be significant fatigue, nerve damage, memory problems, and more
Pharmacological similarity to a known beta-3 agonist, inhibition by a nonselective antagonist, or convergence on a downstream signal would not independently prove direct receptor binding