How vitamin B12 supports energy and nerve health
B12 is involved in making red blood cells, maintaining the protective sheath around nerves and supporting DNA production. That range explains why deficiency can look so different from person to person.
Blood, nerves and energy
Without enough B12, red blood cells form poorly and carry oxygen less efficiently, which is felt as fatigue and breathlessness.
Nerve effects show up as tingling, numbness, unsteadiness or changes in sensation, usually in the hands and feet first.
Why absorption is the usual problem
Most people eat enough B12. The difficulty is absorbing it, which needs healthy stomach lining and a functioning small intestine.
That is why injections work when tablets do not, since they bypass the gut entirely.
Deficiency can develop slowly
The liver stores B12 for a long time, so symptoms often appear gradually over months or years and are easy to attribute to a busy life.
Getting it checked properly
A blood test measures your level and can be combined with folate, ferritin and thyroid tests, since these frequently overlap.
In short
B12 deficiency is easy to test for and very treatable. The key is confirming it rather than assuming it.
This article is general information and does not replace individual clinical advice. If you have symptoms that concern you, speak to our team, your GP or call 111.