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Vitamin D

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Vitamin D is important for bone strength as well as energy levels, mood, and immune health. You can check vitamin D levels using our at-home vitamin D test.
What's included
your discount will be applied at checkout

Why Check Vitamin D levels?

Vitamin D has many important roles within the human body, most notably bone health and muscle function. However, there is growing evidence to suggest that it also plays a vital part in our immune health as well as regulating our energy level, sleep and even mood.

Your body makes vitamin D when it is exposed to sunlight. As the UK has poor sun quality, vitamin D deficiency is common. Find out if you are deficient with our vitamin D blood test.

Vitamin D and bone health

Vitamin D helps the body to absorb calcium which bones need for strength. Without vitamin D, your body will be unable to absorb the key nutrients bones need from the food you eat and this increases your risk of developing osteoporosis.

Osteoporosis is a debilitating disease which weakens bones, so they are fragile and more likely to break. It can take some time to develop but can result in breakages, particularly the wrist and hips. Women of menopausal age are at a greater risk of osteoporosis as their oestrogen levels fall. Therefore, vitamin D is vital for women of this age to prevent fractures and weakened bones. The nutrient can also boost immunity, mood and energy during the menopause, too!

The important role of vitamin D in bone healthy means it is also vital for anyone who participates in regular exercise because it can prevent the development of stress fractures. However, it also has muscular benefits and increases muscle protein synthesis and increased vitamin D levels are associated with greater strength and power.

Vitamin D deficiency
the number of people who have insufficient or deficient levels of vitamin D
optimal levels
of Forth customer improved their vitamin D result between tests.

What impact does vitamin D have on mental health?

There is a growing body of evidence to suggest that vitamin D is important for brain function and that low levels could cause depression.

As well as depression, research has shown that low levels of vitamin D have been associated with premenstrual mood swings in women, mood disorders and cognitive issues.

Studies have also shown that increasing vitamin D levels via supplementation can improve depressive symptoms.

Dr Nicky Keay
the Experts Opinion

Low levels of vitamin D can reduce wellbeing and impair bone, muscle and immune health. However, Vitamin D is an exception to other vitamins in that the main source is not through diet, rather through action of sunlight on the skin. As sunlight can be in short supply in countries like the UK, supplementation is often required and indeed recommended by Public Health England over winter months. It is useful to inform yourself of your vitamin D level by blood testing to know if any symptoms are due to suboptimal levels of Vitamin D and if initiation of supplementation or alteration in dose of supplementation is required.

Dr Nicola Keay
Forth Chief Medical Officer

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 vitamin D?

    Vitamin D is often called the sunshine vitamin because your skin makes it when it is exposed to sunlight. It is a fat-soluble nutrient which has roles in bone health, immune function, energy levels and mood.

    Read more about vitamin D.

  • What is vitamin deficiency?

    Vitamin deficiency occurs when you have a chronic lack of a specific vitamin. If the deficiency is caused by poor nutrition then it is called primary deficiency, but if it’s caused by an underlying condition, it’s known as a secondary deficiency.

    Secondary deficiencies can be caused by things such as malabsorption, chemotherapy, or diseases such as HIV.

    Read more on vitamin deficiency.

  • How can I increase my vitamin D levels?

    Even though there are some dietary sources of vitamin D available (most of which are fortified with it), sunlight exposure is the best source. Because sunlight can be limited in the UK, the entire population is at risk of deficiency. Therefore, Public Health England recommends that all adults and children over one should take a vitamin D supplement containing at least 10 micrograms.

    Vitamin D is essential for strong and healthy bones. Physical and weight-bearing exercises are also good for bone health and help to keep them strong. So, it is also essential to take part in regular physical activity. Equally, vitamin D is important for muscle function, too, so getting enough will also support your muscles and keep them working.

  • What are the symptoms of vitamin D deficiency?

    Low levels of vitamin D can cause the following symptoms:

    • Depression
    • Hair loss
    • Fatigue
    • Muscle pain
    • Recurrent infections
    • Bone pain
  • How do you check vitamin D levels at home?

    If you’re wondering how to test vitamin D levels at home, it couldn’t be easier.

    Our vitamin D blood test requires a small blood sample and makes checking your vitamin D levels privately, fast, affordable, and convenient. All you need to do is collect your sample and send it directly to our accredited lab for analysis. Accurate results will be available within 2 working days of receipt on your secure online dashboard.

  • What should my vitamin D level be UK?

    The recommended normal level of vitamin D in adult men and women is between 50 -175 nmol/L. The optimal recommended level for wellbeing is >75 nmol/L.

    Our vitamin D test kit will give you an accurate measurement of your levels.

  • Is too much vitamin D bad for me?

    If you take too many vitamin D supplements over a prolonged period of time, it can have a negative impact on your health. That’s because it can cause a condition called hypercalcaemia where lots of calcium builds up in the body, resulting in weakened bones or damage to organs such as the heart and kidneys.

    You can monitor the impact supplements are having on your body’s level of vitamin D by taking our vitamin D blood test.

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.

Baseline Plus
Per test
22 Biomarkers Included
Our best selling general health blood test measuring 22 essential biomarkers for good health and wellbeing.
48 Biomarkers Included
Our best value wellbeing check measuring over 45 biomarkers.

Looking for a bespoke test?

Would you prefer to test more biomarkers at the same sample of blood? All our tests are customisable and can be tested in just one sample of blood. Click the button below to add more biomarkers to this test.

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.

Baseline Plus
Per test
22 Biomarkers Included
Our best selling general health blood test measuring 22 essential biomarkers for good health and wellbeing.
48 Biomarkers Included
Our best value wellbeing check measuring over 45 biomarkers.
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. 

Service Status

Kit Dispatch

Kits ordered before 2pm from Monday to Friday continue to be dispatched same day via First Class Royal Mail. After 2pm your kit will be dispatched the next working day. Orders placed on the weekend will be despatched Monday.

Postal Service

There may be some delays in parts of the UK while the Royal Mail catches up with their Christmas backlog. Click here for updates on the Royal Mail service.

Lab Analysis

Our labs are operating as normal.

Doctor/nurse reviews

Our doctors and nurses are currently working remotely and continue to review results.

Home phlebotomy appointments

Our home phlebotomy service is running but please be aware, if you or anyone in your household have experienced symptoms of COVID-19 within the last 14 days, due to the current government guidelines, we are unable to arrange an appointment at this time. Due to a high demand for nurses, along with current covid restrictions around the UK, there may be a delay in providing an appointment.

Customer service

Our customer service team are currently working from home, available to answer any questions via email.

Results dashboard

You can continue to access your results as normal either through your browser or via our iOS or Android app.


If you are an employer and would like to order multiple tests for your employees, please complete the form below.