Vitamin D



What is Vitamin D and why is it important?

Vitamin D is actually a hormone which helps regulate the amount of key minerals such as calcium and phosphate in the body. It is crucial for maintaining  healthy bones, teeth and muscles. Vitamin D also has been linked to other

We maintain health Vitamin D  levels n three ways:

  • We make it in the the skin from sunlight exposure
  • We can find sources of vitamin D  from our diet
  • We can take  vitamin D supplementation

In the UK, from around the end of March to the end of September, most people can obtain adequate amounts of vitamin D from direct sunlight on the skin when outdoors and a healthy balanced diet.

Between October and March, the sunlight is generally not strong enough to make adequate vitamin D, so it must be obtained from the diet or supplementation.

Who is this test for?

This test will allow you to know exactly what your vitamin D levels are now. We will let you know if you have enough, or if you require supplementation.

There are two types of Vitamin D called D2 and D3. Vitamin D2 is made in plants and Vitamin D3 is produced in the skin with sunlight exposure. Both forms can be found in the diet and in supplements. Our Vitamin D test measures both D2 and D3. The result produced is the total of both D2 and D3 together.

People who may be at risk of Vitamin D deficiency include:

  • The elderly, especially if frail/house-bound
  • People with dark skin (African, African-Caribbean and South Asian ethnicities)
  • People who are very overweight (obese) or have had gastric bypass surgeries
  • Pregnant women and women who are breastfeeding
  • Anyone who may spend very little time outdoors
  • People with certain conditions, such as liver disease, kidney disease or cystic fibrosis (CF)
  • People with malabsorption conditions e.g. Coeliac’s disease or Crohn's disease
  • People who have already been diagnosed with bone disease such as osteoporosisosteomalacia, or Paget’s disease

Please note: these tests are available for people aged over 18 only.  Please collect and post your sample to us Monday-Thursday, to avoid delays over the weekend. In a small number of cases, it may not always be possible to provide a result, please see our terms and conditions for details.


What are the symptoms of Vitamin D deficiency?

Most people who are Vitamin D deficient do not show any symptoms at all.

Vitamin D deficiency can lead to bone conditions such as osteoporosis, osteomalacia in adults, or Paget’s disease.

These conditions may cause bone pain, muscle weakness and increase the risk of bone fractures.

There are many news articles and publications in the press and online which suggest Vitamin D deficiency has been linked with many other health conditions. However, the scientific evidence to prove these links have not yet been established to make any firm conclusions.

What does the result mean?

Interpretation of Vitamin D results:

  • Less than 10 nmol/L: Deficient, suggests Vitamin D replacement. You should contact a health care professional
  • 10 - 35 nmol/L: Insufficient, suggests Vitamin D supplementation would be appropriate.
  • 36 - 60 nmol/L: Adequate. For optimal bone health, concentrations at the upper end of the reference range may be preferable and advice regarding diet and safe sun exposure may be appropriate.
  • Greater than 60 nmol/L: Optimal.

Can I test whilst on supplements?

Vitamin D supplements:

There is no need to stop taking vitamin D supplements before doing this test

Biotin supplements:

Supplements that contain biotin (also known as vitamin B7) can sometimes affect vitamin D testing. We recommend leaving the following amount of time between biotin supplement and our blood test:

Less than 10,000 mcg/day (10 mg/day) of biotin – 24 hours

10,000 mcg/day or above (10 mg/day or above) of biotin – 72 hours

Useful links

How it works

Order a test online

Order a test online

All tests are confidential, and designed simply to help you self diagnose.

Home testing

Home testing

All tests are designed to be able to be carried out in the comfort of your own home, simply follow the package instructions.

Post it back to us

Post it back to us

For the best results all tests should be returned in the pre-paid package provided as soon as they are carried out.

See results online

See results online

We will contact you by your chosen method to let you know your results are ready (typically 24-48 hours). You will then be able to log into your personal dashboard and view your results.

Collecting your blood sample

Your personal Dashboard

Your personal Dashboard

Designed by clinicians to enable you to clearly and safely interpret your results with different charts and views to help you monitor and aid self-improvement.