---
title: "Vitamin B12 deficiency: symptoms, causes & treatment"
description: "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."
url: "https://www.sanarahealth.co.uk/conditions/vitamin-b12-deficiency/"
source: "Sanara Health"
licence: "Quote with attribution and a link to the url above."
---
# 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.

[See our vitamin b12 deficiency support →](https://www.sanarahealth.co.uk/compare/)

Go deeper

## Related guides

[Vitamin B12 deficiency UK: symptoms, causes and treatment — Low vitamin B12 in the UK — symptoms, who is at risk, blood tests, treatment options and when to see your GP.](https://www.sanarahealth.co.uk/guides/vitamin-b12-deficiency-uk/)

Available without prescription

## Products that can help

[Everyday health — Vitamin D3: 1000 IU explained](https://www.sanarahealth.co.uk/supplements/vitamin-d3-1000iu/)

[Everyday health — Omega-3 fish oil](https://www.sanarahealth.co.uk/supplements/omega-3-fish-oil/)

[Everyday health — Daily multivitamins](https://www.sanarahealth.co.uk/supplements/daily-multivitamin/)