25-hydroxyvitamin-d3 (CAS 19356-17-3) is a prehormone created by the liver by the cholecalciferol 25-hydroxylase enzyme during hydroxylation of vitamin D3. It is converted in kidneys into the secosteroidhormone calcitriol, the active form of vitamin D, by the 25(OH)D-1a-hydroxylase enzyme. Similarly, it can be converted in kidneys into 24-hydroxycalcidiol through 24-hydroxylation. The name 25-hydroxyvitamin-d3 may also be abbreviated to 25(OH)D, or it may be known as calcidiol, 25-hydroxycholecalciferol, and its international nonproprietary name (INN) of calcifediol.

25-hydroxyvitamin-d3 was first identified by Michael F. Holick, a translation physician-scientist from U.S., and is now measured by physicians across the globe in order to determine the amount of vitamin D in body of a patient through a 25-hydroxy vitamin D blood test. The concentration of 25-hydroxyvitamin-d3 in the blood is considered the best measure of vitamin D status in an individual.

Labeled 25-hydroxyvitaminThe test is used to determine whether a patient is experiencing a vitamin D deficiency and to diagnose the tendency of risk of such a condition. Patients suffering from osteoporosis, malabsorption, chronic kidney disease, obesity, and some infections are especially prone to vitamin D deficiencies and so are particularly suited to a such screening. The results of the blood test are then used to determine the appropriate treatment, which may consist of aggressive therapies. Although people living at high latitudes or where there is limited sun exposure often experience vitamin D deficiency, the test is not suitable for entire populations. Lower risk patients are more likely to be advised to take an over-the-counter vitamin D supplement than to undergo the blood test.

A normal level of 25-hydroxyvitamin-d3 will depend on external factors such as age and geographical location. MedlinePlus puts normal range at 30.0 to 74.0 nanograms per milliliter, while another study published in the Journal of Nutrition defined less than 32 nanograms per milliliter as vitamin D deficiency. Furthermore, it is possible for 25-hydroxyvitamin-d3 levels to be too high. A study of 25,000 volunteers, conducted by the University of California, found that those with high levels of 25-hydroxyvitamin-d3 resulted in a higher risk of colon cancer at one-fifth of normal rates.

In order to undertake mass spectrometry studies we sell the deuterium labeled 25-hydroxyvitamin-d3 which is available in 1 milligram or 5 milligram orders at 98 percent purity or below. It is considered to be a hazardous substance but holds no DEA certification.

We are proud to offer a selection of stable labeled vitamins. For your convenience, we sell unlabeled vitamins alongside our list of labeled vitamins. Our selection includes CertiMass™ Reference Standards, which are standard solutions for many of our premier compounds

If you are unable to find the desired vitamin in our catalog, please contact us by email or phone (610-337-3762) we will be more than happy to provide a quote on custom synthetic work.