Feel energized and clear headed
This is because vitamin B12 plays a key role in the DNA production required to make red blood cells
Correcting a genuine deficiency may help you feel more energetic, and any weight benefit typically comes indirectly from feeling well enough to be more active, not from the injection itself
It can lead to a better functioning metabolism, aids in weight management, and promotes nutrient utilization
B6 supports red blood cell production and energy conversion, methionine aids in the metabolism of fats, inositol boosts energy production, choline accelerates fat metabolism, and B1 and B2 support the immune system and fuel metabolism
But, there are several reports supporting an association between inadequate B12 levels and premature hair graying, which is grey hair that onsets before the ages of 20-30 (depending on the demographic) (12)