Normal range: 30 – 100 ng/mL (higher is better)
Vitamin D is essential for calcium absorption, bone health, immune function, and cardiovascular health. Despite its name, it acts more like a hormone than a vitamin. Deficiency is remarkably common, affecting an estimated 40% of US adults. Levels below 20 ng/mL are deficient, 20-30 ng/mL is insufficient, and above 30 ng/mL is sufficient. Most experts now recommend aiming for at least 30 ng/mL.
A normal Vitamin D is 30 – 100 ng/mL. Higher is better.
Insufficient sun exposure is the leading cause of low vitamin D, especially for people living at northern latitudes, those with darker skin, and those who spend most of their time indoors. Obesity traps vitamin D in fat tissue, lowering blood levels. Malabsorption from celiac disease, Crohn's disease, or gastric bypass also contributes.
Older adults produce less vitamin D in the skin. Kidney and liver disease impair conversion to the active form. Several medications increase vitamin D breakdown, including anticonvulsants, glucocorticoids, and certain HIV medications.
Getting 15-20 minutes of midday sun exposure several times per week helps (though sunscreen and darker skin reduce production). Dietary sources include fatty fish, egg yolks, and fortified milk. Most people with low levels benefit from supplementation, typically 1,000-2,000 IU daily, though your doctor may recommend higher doses to correct a deficiency. Vitamin D3 (cholecalciferol) is generally preferred over D2.
Vitamin D is most highly correlated with Vitamin B12 and Estimated Glomerular Filtration Rate. Here are the top biomarkers correlated with Vitamin D, based on 500,000 tests done by Empirical Health.
The percentage shows how strongly two biomarkers move together. A higher number means the relationship is stronger. Green = rises and falls together. Orange = one rises as the other falls.
You can test your Vitamin D for $190 as part of Empirical's comprehensive health panel, which includes 100 biomarkers.
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