Dietary Sources High in Vitamin B12 As discussed above, the average adults daily requirement is 2.4 micrograms a day, with the best dietary sources of Vitamin B12 coming from animal products
A typical dosage is 1000 mcg (1 mg) administered IM or subcutaneously
Vitamin B12 shots are most effective when taken at regular intervals (usually weekly or monthly) A regular healthy individual would also benefit from having vitamin B12 injections, this can promote a healthier lifestyle, increase energy and production, speed up a metabolism and its even been linked to lifting mood and decreasing depression
You still need to manage your caloric intake through willpower, habit, and dietary strategy
The above is usually talked of in terms of 'anaemia', but it does show that there is a complicated link between B12, B6, folic acid, zinc and vitamin D levels, chronic disease (anaemia of chronic disease) and how the body 'manages' serum iron, ferritin, and transferrin iron saturation and keeps these in balance (or not, as in your case)