Many are unaware that vitamin D is not officially a vitamin – but actually a prohormone. In fact, we make most of our vitamin D when our skin is exposed to sunlight.

Statistics show a third of Americans have insufficient levels of vitamin D, with a leading cause being lack of sun exposure. This is common in northern climates where people don’t spend as much time outdoors, but studies indicate that even people in sunnier regions are often deficient due to concerns about the ill effects of too much sun.

Why the Concern About Low Vitamin D?

Vitamin D is important because it has a complex regulatory effect upon calcium in our bodies and in the mineralization of our bones. But that’s only skimming the surface of its function. Additional research shows vitamin D can play a protective role against certain cancers, development of diabetes and heart disease.

Vitamin D deficiencies are associated with hyperinsulinemia and increased belly fat, as well as contributing to psoriasis and acne. Additionally, sufficient levels of vitamin D, estrogen and testosterone are important for maintaining bone health in the menopause years.

Learn More About Vitamin D


Webinar: Exploring Other Uses of Vitamin D

Blog: The Phenomenon of Vitamin D

Blog: How to Supplement with Vitamin D & Melatonin after Melanoma

Datasheet: Vitamin D Profile

Vitamin D Testing

To restore the vital balance of hormones, we first need a detailed, accurate measurement of hormone levels. Not just numbers, but an assessment that offers real meaning.


Blood Spot Hormone Test Kit - ZRT Laboratory

Vitamin D Test Kit Includes:

Vitamin D Profile – 25-OH D2, 25-OH D3, Total (Sample Report)


Reference Information

Testing Catalog

Overview of Kits

ZRT Test Directory & Abbreviations

Dried Blood Spot Reference Ranges


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