Vitamin B12 (cobalamin) deficiency can affect the blood, nerves, and brain. Symptoms often develop slowly and can be subtle at first.
Common symptoms
🩸 Blood-related (anemia)
- Fatigue or low energy
- Pale or slightly yellow skin
- Shortness of breath (especially on exertion)
- Dizziness or lightheadedness
- Fast heartbeat
🧠 Nerve and neurological symptoms
- Tingling or “pins and needles” in hands or feet
- Numbness
- Balance problems or unsteady walking
- Muscle weakness
- Loss of coordination
🧠 Brain and mood changes
- Memory problems or forgetfulness
- Difficulty concentrating (“brain fog”)
- Irritability or mood changes
- Depression or low mood
- In severe cases: confusion or dementia-like symptoms
👅 Mouth and digestive symptoms
- Sore, red tongue (glossitis)
- Mouth ulcers
- Loss of appetite
- Weight loss
- Nausea or mild digestive upset
Important warning signs (seek medical attention)
- Rapidly worsening numbness or weakness
- Severe balance problems or frequent falls
- Confusion or significant mental changes
- Symptoms of severe anemia (chest pain, extreme fatigue, fainting)
Common causes
- Low dietary intake (especially strict vegan diets without supplementation)
- Poor absorption (pernicious anemia, stomach issues, gastric surgery)
- Long-term use of certain medicines (e.g., metformin, acid-reducing drugs)
Good to know
- B12 deficiency is usually treatable and reversible early, especially blood symptoms.
- Nerve damage can become partially or fully permanent if untreated for too long.
If you want, tell me your symptoms or lab results (like B12 level), and I can help interpret what they might mean.
