Vitamin D (25-hydroxyvitamin D) – Vitamin D supports bone health, immune function, and muscle strength. The 25-hydroxyvitamin D test is the standard measure of your status.
What Vitamin D measures
Vitamin D measures your stored vitamin D level, reflecting intake and sun exposure over recent weeks.
Typical ranges
Roughly 20-50 ng/mL is often considered sufficient; below 20 ng/mL is typically deficient. Optimal targets vary. Reference ranges differ between laboratories and by age and sex, so always read your result against the range printed on your own report.
What high results can mean
Usually from over-supplementation; very high levels can be harmful.
What low results can mean
Deficiency, linked to bone loss, fatigue, and weakened immunity – often corrected with supplementation and sunlight.
How the test is done
A blood sample; no fasting required. At-home collection works well for this marker when the sample is processed by a certified lab.
FAQ
What is a normal Vitamin D level?
Roughly 20-50 ng/mL is often considered sufficient; below 20 ng/mL is typically deficient. Optimal targets vary. Your ideal target depends on your age, sex, and health history, so review results with a clinician.
What does a high Vitamin D result mean?
Usually from over-supplementation; very high levels can be harmful.
Can I test Vitamin D at home?
Yes. A blood sample; no fasting required. An at-home sample processed by a certified lab gives reliable results.
This article is educational and not a substitute for medical advice. Discuss your results with a qualified clinician.