We know that B12 recovery from bile would be a problem but this only contributes 5mcg to the picture, so I think its an open question
As a result, delivery within 2 business days is not guaranteed
Pushing through excessive fatigue during aggressive fat loss protocols leads to overtraining syndrome, which actually increases muscle catabolism and slows fat loss
Importantly, these changes were observed without significant reductions in food consumption, pointing to enhanced energy metabolism rather than appetite suppression as the primary mechanism
Joseph, MO 483 Issued April 21, 2009 [Internet]
It works by increasing your levels of vitamin B12 so that you can make red blood cells that work properly to carry oxygen around your body