Vitamin D tests involve taking a blood sample to measure the vitamin D levels in your bloodstream. There are two forms of vitamin D in the blood: 25-hydroxy vitamin D, or calcidiol, and 1,25-dihydroxy ...

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 ...

At-home vitamin D tests may provide insights into your health. When followed by a consultation with a doctor, it can be a first step in managing a common nutritional deficiency. Vitamin D helps you ...

Dr. Lacey Anderson explains why most people don’t need routine vitamin testing and what to do instead. Here’s what to know. An increasing amount of health advice on social media is encouraging people ...

Reading vitamin labels can sometimes be a mystifying experience. To help clarify, here are the various FDA vitamin labels and what they all mean.