Medically reviewed by Soma Mandal, MD A vitamin D test is a blood test that measures the level of vitamin D (calciferol) in ...

Vitamin D is a fat-soluble vitamin that helps the body absorb calcium, magnesium, and phosphate, which are important for bone ...

But vitamin prices are often deceiving. It’s typically not necessary to spend top dollar on supplements. The inexpensive options can be just as good—if you pick the right ones. To do that ...