Vitamin B12 deficiency: signs and who’s at risk

Vitamin B12 keeps your nerves and blood cells healthy. A real deficiency causes clear problems — but B12 is also widely sold as an “energy” booster. The truth: if your levels are fine, extra B12 won’t give you more energy. It only helps when you’re actually low.

Signs of low B12

• persistent fatigue and weakness;
• tingling or numbness in hands and feet;
• brain fog, memory or mood changes;
• a sore, smooth tongue;
• pale skin.

These can have many causes, so they point to testing, not self-diagnosis.

Who’s at risk

• Vegans and strict vegetarians — B12 comes almost only from animal foods;
• Adults over 50 — absorption drops with age;
• people on long-term acid-reducing medication (PPIs) or with gut conditions;
• after certain gut surgeries.

Testing and food

If you’re in a risk group or have symptoms, ask your doctor for a blood test. Food sources are meat, fish, eggs and dairy; vegans should rely on fortified foods or a supplement, since plants don’t provide B12. Supplementing without a reason won’t boost energy in people who aren’t deficient.

Frequently asked questions

Does B12 give you more energy?

Only if you’re deficient. In people with normal B12, extra doses don’t improve energy or focus despite the marketing.

Who should take a B12 supplement?

Vegans and strict vegetarians (from fortified foods or a supplement), and anyone found low on testing — often older adults or people on acid-reducing drugs.

What are the first signs of low B12?

Commonly fatigue, tingling or numbness in the hands and feet, and brain fog. These need a blood test to confirm, as they overlap with other conditions.

This article is educational and not medical advice. Persistent neurological symptoms need prompt medical attention.