Does vitamin b12 deficiency cause fatigue?

The body needs vitamin B12 for red blood cell production and normal nervous-system function. When levels are low, anaemia can develop and reduce the body’s ability to carry oxygen efficiently. This may leave you unusually tired, short of breath with activity, pale, or aware of a fast heartbeat. Deficiency may also affect nerves, causing tingling, numbness, poor balance, or difficulty concentrating. Fatigue has many possible explanations, including sleep problems, infection, stress, thyroid disorders, and other forms of anaemia.

Make an appointment if tiredness is lasting, worsening, or interfering with work, study, or daily tasks. Explain when it began, how sleep affects it, what you eat, and whether you have digestive symptoms or use medicines that may affect absorption. A clinician can decide whether blood tests are appropriate and look for the cause of a low B12 level. Treatment can involve food choices, prescribed B12 replacement, or managing a condition that prevents absorption.

Seek urgent medical care for fatigue with chest pain, severe shortness of breath, fainting, confusion, black stools, vomiting blood, or a new irregular heartbeat. Arrange prompt assessment for rapidly worsening weakness, new difficulty walking, or numbness that is spreading, because these symptoms can need timely evaluation.

Ask whether your fatigue could reflect anaemia or another cause, which tests may clarify the picture, and whether your diet or absorption needs review. Tell the clinician about vegan or restrictive eating, stomach or bowel surgery, digestive disease, and regular medicines.