USANA's Vitamin D product provides the following warning on its label:

"Keep out of reach of children. Consult your physician if you are pregnant, nursing, taking a prescription drug, or have a medical condition. If you exceed the established Upper Limit (UL) of 4000 IU/d for vitamin D intake, regular blood tests for vitamin D and calcium status are suggested."

In addition to the standard dietary supplement warning, the warning about blood tests is a general warning added as a precaution.

There has never been a clinically documented case of vitamin D toxicity below 30,000 IU.  However, the official upper limit for vitamin D is currently set at 4,000 IU, and as a company we feel it is our duty to promote awareness and education among our customers.

Unfortunately, there are many people who may take dietary supplements without thought of excess or who may not wish to follow label directions.  We have included this additional warning because while vitamin D deficiencies are widespread, vitamin D products are not something that should be taken without regard to safety.

As stated before, adding in a factor for safety, most experts agree that 10,000 IU or less can be taken safely by normally healthy individuals.  If someone has concern about safety, is regularly exposed to unusual levels of sunlight, or wants to be absolutely certain of their vitamin D blood levels, we suggest getting vitamin D levels checked before taking large supplemental levels of vitamin D.  (Please note that this is not generally necessary, however, when consuming the recommended dosages of the HealthPak or Essentials, Active Calcium, and BiOmega.)