Blood Test Markers

What does low B12 mean?

Low B12 means your body doesn't have enough vitamin B12 — also called **cobalamin** — circulating to keep up with what your cells need it for. That's a long list: making red blood cells, copying DNA, and maintaining the myelin sheath that wraps your nerves so signals travel cleanly. When B12 runs low, those processes get sloppy. You feel it before the bloodwork shows it.