2. Feeling exceptionally fatigued
If you find that you are having a hard time staying awake or like you aren’t well-rested, no matter how much sleep you have gotten, it’s very likely that you are suffering from a vitamin B12 deficiency.
As mentioned, this vitamin aids in the production of red blood cells. Since red blood cells transport oxygen to all of the organs in the body – including your brain.
If your organs aren’t getting the oxygen they need, you will be left feeling extremely tired.
In fact, fatigue is one of the most common signs of a vitamin B12 deficiency.