Vitamin B12 deficiency: symptoms, causes & treatment

Low B12 causes fatigue, pins and needles and low mood — common in older adults, vegans and people with absorption problems. Needs blood tests to diagnose.

Editorial information by Kaiser Khan. Not clinically reviewed.

Symptoms

Fatigue
Pins and needles in hands or feet
Sore red tongue
Low mood or brain fog
Balance problems if severe

Why it happens

Pernicious anaemia (autoimmune), vegan diet without supplementation, metformin use, or stomach surgery affecting absorption.

Treatment

B12 replacement therapy or high-dose tablets after confirmed deficiency — usually via GP. Online blood tests can screen levels.

Self-care that helps

Vegans should use fortified foods or supplements; do not take high-dose B12 without testing if symptoms persist.

When to get help

Worsening numbness, weakness or confusion — GP review urgently.

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Vitamin B12 deficiency UK: symptoms, causes and treatment

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