your discount will be applied at checkout
your 10% discount will be applied at checkout
  • Doctor reviewed results
  • Results in 48hrs
What's included
  • Finger prick kit
  • Accredited lab analysis
  • Market leading results dashboard
  • Postage & packaging
  • Results within 2 working days of receipt
  • Reviewed by a doctor or nurse
your discount will be applied at checkout

Vitamin B12 Test

In Stock
Free Delivery
Results within 2 working days
If you’re feeling tired and weak a vitamin B12 test might explain why. Low levels cause fatigue, and a home B12 test will give you a quick and accurate measurement.
What's included
  • Finger prick kit
  • Accredited lab analysis
  • Market leading results dashboard
  • Postage & packaging
  • Results within 2 working days of receipt
  • Reviewed by a doctor or nurse
your discount will be applied at checkout

Why Check Vitamin B12 levels?

Vitamin B12 alongside folate is vital for the formation of red blood cells and its also important for nerve health.

Because red blood cells contain the protein haemoglobin, whose primary role is to transport oxygen around the body, low vitamin B12 levels can result in fewer red blood cells or a low amount of haemoglobin. Reduced levels of B12 can therefore lead to fatigue, lethargy, and feelings of weakness.

What is
Active B12?

Our vitamin B12 blood test measures active B12 rather than total B12 and is the most accurate way of measuring your available level of vitamin B12. An active B12 test is the best early indicator of possible deficiency because it measures the total amount of B12 available for your body to use. The human body can store enough vitamin B12 to last a few years but certain groups are at a greater risk of deficiency because their stores will be depleted or they may have issues absorbing it from their diet.

Prolonged vitamin B12 deficiency can lead to anaemia, so spotting it early can help prevent this.

Vitamin B12 deficiency
1 in 10 people
in the UK are believed to be deficient in vitamin B12 (Pernicous Anemia Society).
Optimal levels
50% of customers
improved their B12 result between tests.

Who are most at risk of vitamin B12 deficiency?

Vitamin B12 is mostly found in meat as well as chicken and fish so vegans and vegetarians are at a greater risk of vitamin deficiencies including B12. Therefore, a vegan or vegetarian diet must be planned appropriately, which may mean eating fortified foods 2-3 times per day or by taking a vitamin B12 supplement.

Older people are also at an increased risk of vitamin B12 deficiency and a folate deficiency, possibly due to poor dietary intake. 

improve your unique self

Want to improve your health & wellbeing? Forth gives you insight into your body’s key biomarkers. By tracking essential markers overtime you can build a picture of your own unique self and discover how your body responds to the changes you make so you can reach your personal best.

Chose a health check

Order your home blood test online and we’ll deliver it straight to your letterbox.

Collect your sample

Our finger prick blood test kit has everything you need. Just collect your sample, and return it to our accredited lab, using the Tracked-24 envelope supplied.

Fast, accurate results

Your blood test results will be reviewed by our healthcare team and uploaded to your dashboard within 24-48hrs. Along with simple explanations and expert advice on how to make improvements.

Health Dashboard

View your results on our app and web platform, which gives you key information, bespoke advice, and allows you to dive deeper to find out more.

Advice by medical experts

We don’t just provide your levels and leave you to it; our team of medical experts interpret any out-of range results and provide advice specifically tailored to you.


Our app allows you to compare your biomarker results against other individuals of a similar age and gender, so you’re able to benchmark your health more accurately, and identify any areas that need improvement.

Track changes over time

One test is a snapshot, but test repeatedly over time and you’ll see how your body reacts, adapts and changes to elements like diet, exercise, supplements, and more. The more information you have, the clearer the picture of your own unique physiology, and the greater your understanding of what your body needs to perform at its best.

Fast & Accurate

Fast & accurate analysis from accredited laboratory.


Secure access to online results.


Convenient tests can be done at home.

Online Dashboard

Online dashboard which tracks results over time.

Frequently asked questions

Take the guess work out of your health. Here are some of the most frequently asked questions we get asked. If you need anything else try our help section.

  • What is active B12?

    Active B12 is the total amount of vitamin B12 available for use within your body. It is essential for the development of red blood cells as well as DNA. It also has important roles in nerve function.

  • What is the normal level of B12?

    The vitamin B12 test will show if your active vitamin B12 levels are above the minimum normal range of 37.5 pmol/L.

  • What are the symptoms of low Vitamin B12

    Low vitamin B12 levels can cause:

    • Fatigue
    • Sore tongue
    • Mouth ulcers
    • Blurred vision
    • Pins and needles
    • Irritability
    • Depression
    • Problems remembering things
    • Changes in the way you walk or move
    • Pale yellow tinge to the skin
  • Do I need to take vitamin B12 supplements?

    If you eat a healthy, balanced diet you should acquire all the vitamins and minerals your body needs to function properly. However, someone who is on a vegan or vegetarian diet might need to take a vitamin B12 supplement, particularly because most of the vitamin comes from animal-based sources. There are some vitamin B12 fortified sources but these may be limited.

  • How to check B12 levels?

    You can check vitamin B12 levels using our at-home vitamin B12 test kit. Our test enables you to check your active B12 levels quickly, easily, and affordably. Simply send your sample direct to our UKAS accredited lab and your accurate result will be available within 48hrs on our secure digital dashboard.

  • What’s the difference between total and active B12?

    Active B12 is best way to test B12 as it only measures the form of vitamin B12 that is available to be used by the body. A total B12 test, which is the standard test offered by the NHS, measures the total amount of both active and inactive B12.

    The problem with testing for total B12 is that the test may show as normal but mask low levels of active B12. Active B12 typically makes up around 10% to 30% of B12 in the body.

    Read more in our blog.

  • What does high B12 mean?

    Generally, high levels of vitamin B12 are not considered to be toxic which is why there isn’t an upper range. Very high levels are rare but are seen in some types of leukaemia or liver disease.

  • How can I increase my Vitamin B12 levels?

    The human body doesn’t make vitamin B12 which makes it an essential vitamin. That means it must be absorbed through the diet or by taking a supplement.

    So, the best way to naturally increase your vitamin B12 levels is to eat a wide variety of foods and be sure to incorporate some rich B12 sources.

Upgrade your test

All our tests are designed by our expert team of scientists who have taken the latest research to bring you the most relevant biomarkers to improve your health. Here are some alternative tests that cover essential biomarkers.

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Our best selling health check measuring 22 essential biomarkers for good health and wellbeing.
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Looking for a bespoke test?

Want to add more biomarkers to your test? That’s no problem. All of our tests can be personalised.  Just use our ‘customise this test’ button below to see the list of biomarkers which you can add to your test and get analysed at the same time.