What Should Your Vitamin D3 Level Be?

Vitamin D refers collectively to two substances. These substances are ergocalciferol, known as vitamin D-2 and cholecalciferol, known as vitamin D-3. Both substances are biologically inactive on their own. Your liver converts them to 25-hydroxy vitamin D, which is the active vitamin D form. Therefore, vitamin D-3 levels are not generally measured and there is no established normal level. Instead, A 25-hydroxy vitamin D test is used to determine your vitamin D levels.

Vitamin D Significance

Your skin produces vitamin D from sun exposure and it is also found in your diet. Vitamin D plays an important role in helping your body absorb calcium, which is crucial for bone health. Vitamin D is also important to your muscles, nerves and immune system, according to the Office of Dietary Supplements. The recommended daily intake for adults under age 70 is 600 IU and 800 IU for adults above age 70.

Vitamin D-2 vs Vitamin D-3

Vitamin D-3 is the naturally occurring vitamin D form that is made when sunlight strikes your skin. You also get this form from animal products. Vitamin D-2 is the commercial vitamin D form, primarily derived from yeast. It is used to fortify cereal and other foods. It is also the primary form used in vitamin supplements.

Normal Active Levels

A 5-hydroxy vitamin D test is the most accurate way to measure your vitamin D levels, according to Medline Plus. Normal values range based on the laboratory, so use the normal ranges from the laboratory that does your test. Your doctor can analyze your results to determine your vitamin D status. Normal levels range from 30 to 74 ng/mL, according to Medline Plus.

Potency

Because both vitamin D forms are inactive and your liver converts them to an active form, vitamin D-2 and D-3 have been considered equal and interchangeable substances. However, researchers at Creighton University in Nebraska studied the physiological vitamin D-2 vs D-3 effects. According to the study, published in the March, 2011 issue of "The Journal of Clinical Endocrinology and Metabolism," vitamin D-3 is 87 percent more potent than D-2 at raising 5-hydroxy vitamin D.

Maintaining Healthy Levels

If your vitamin D levels are lower than normal, your doctor may recommend increasing your sun exposure and dietary animal product intake. Your doctor may also recommend vitamin D supplements. Most vitamin D supplements use vitamin D-2, however many high quality supplements use vitamin D-3. Consult your doctor before taking vitamin D supplements.