There are two forms of vitamin D in the blood: 25-hydroxy vitamin D, or calcidiol, and 1,25-dihydroxy vitamin D, or calcitriol. Tests will measure the amount of 25-hydroxy vitamin D in the blood. This ...

Vitamin D is vital for immunity, brain health, strong bones, and overall well-being, but taking in too much from supplements ...

A doctor explains who truly needs a vitamin D supplement in the winter, how to tell if you're deficient, and when ...

Vitamin D tests certified by the U.S. Centers for Disease Control and Prevention (CDC) Clinical Standardization Programs (CSP) are well calibrated overall, according to a new study presented Sunday at ...

Some vitamin D tests may give misleading results despite progress made in recent years to improve the quality of these assays, according to the US Centers for Disease Control and Prevention (CDC).

We tested the best vitamin deficiency tests from LetsGetChecked, Everlywell, and LabCorp, and our testers found them easy to use and informative. Learn more about the best vitamin deficiency tests ...

Vitamin D deficiency is very common, especially during the winter months with less sunlight. Add these foods to your diet to help.

Imagine glancing in the mirror and noticing dull skin, flaky patches, or your hairline looking thinner than before. These might not be mere cosmetic issues — they could be early signals that your body ...

In response to growing awareness of the importance of vitamin D, many people are turning to supplements to ensure they meet ...

WASHINGTON — The nation’s largest medical lab company says it recently discovered and fixed a problem that led to inaccuracies in a small number of tests for vitamin D deficiency. Quest Diagnostics of ...

Vitamin D helps your body absorb calcium, supports bone health, and lowers inflammation.Supplementing with vitamin D can lower LDL and total cholesterol, but doesn't affect HDL cholesterol.High doses ...