B12 is an essential vitamin that plays an important role in making DNA, maintaining nerve health, and producing red blood cells
For many people, especially those with certain health conditions, this process doesn't work well
Because of this, using a pill form of the supplement creates an additional step for transferring the B12 into the bloodstream and can cause your body to absorb less of the vitamin
Oral supplements go through the digestive system, which slows absorption and limits how much your body can take in at one time
The amount varies depending on age, dietary intake, and medical conditions
If youre feeling tired, have nerve problems, or notice other symptoms, see a doctor