Become a Member and get exclusive discounted Prices and Deals.
Vitamin D Test 101
It is estimated that 42 percent of U.S. adults have a sub-optimal vitamin D level.
Vitamin D, which is measured as 25-hydroxyvitamin D (25OH-D), is a fat-soluble vitamin that is responsible for multiple biological processes. Vitamin D, which has always been known for its capacity to support the absorption of calcium, has more recently been found to support immune function, a healthy inflammatory response, and muscle function. A low vitamin D level is associated with a higher risk for various chronic health concerns, including heart disease and diabetes.
Unlike vitamins that must be acquired from outside sources, humans can make vitamin D in their skin with adequate exposure to sunlight. Because we do not get as much sunlight as our ancestors, and because we might not consume adequate dietary sources of vitamin D, many individuals are at risk for too low of a level. A too high level of vitamin D can also occur, but this is much less common and is nearly always associated with excessive supplementation. Thorne's Vitamin D Test measures total vitamin D, which includes the two common forms of vitamin D ‐ D2 (25OH-D2) and D3 (25OH-D3). 25OH-D3 includes the amount derived from internal production, as well as the amount derived from diet and supplementation; whereas, 25OH-D2 reflects only what is acquired in the diet or from supplementation. Together, these two biomarkers make up an individual's total 25OH-D level.
A healthy vitamin D level can be crucial for optimal athletic performance, bone repair after exercise or injury, normal muscle function, healthy immune function, and cardiovascular health. Therefore, it is widely accepted that athletes, compared to non-athletes, should strive to maintain a higher than sufficient level of vitamin D.
Test taker must be 18+ and reside in the U.S.
At-home tests are not permitted for use in:
- Armed Forces Americas
- Armed Forces Europe
- Armed Forces Pacific
- American Samoa
- Northern Mariana Islands
- New Jersey
- New York
- Rhode Island
- United States Minor Outlying Islands
How it works
1 • Delivered
After purchasing, all home-test materials are delivered to your door
2 • Locate Barcode
Locate the barcode included with your kit and enter at thorne.com
3 • Complete Collection
Complete your test collection and return with prepaid shipping
4 • Reviewed
Your results are reviewed by an independent board-certified physician
5 • Receive Results
You'll receive your results & personalized recommendations within 7-9 days