Lets explore all the reasons, and see what you should do
Instead of taking a single active ingredient, a combination of all of the natural B12 forms is the optimal solution as it mirrors the B12 content in foods
This is what we prescribe and administer at Sebastian Rose
These include: Meat Fish Poultry Milk Eggs Fortified breakfast cereals Fortified breads Fortified nutritional yeasts Fortified plant milks If you follow a vegan diet (meaning you don't eat any animal products, including meat, milk, cheese, and eggs) or you're a vegetarian who doesn't eat enough eggs or dairy products, you could be lacking in vitamin B12
Leafy green vegetables, beans, and peas also have B vitamins
In practice, this combination would need to be evaluated by a supervising physician with careful monitoring