Our Vitamin D3 is derived from the lanolin in sheep's wool. No sheep are harmed in this process; however, the Cholecalciferol (Vitamin D3) does come from an animal source.

We recommend taking our Vitamin D3 only every three days due to the nutritional levels in our capsules. The recommended dosage is one 5,000 IU soft-gel capsule every three days. A prominent group of researchers from leading institutions such as the University of Toronto, Brigham and Women’s Hospital, Tufts University, and University Hospital in Zurich, Switzerland found that there is little benefit of taking 400 IU of Vitamin D3 or less per day. The study found the body can only benefit from taking Vitamin D3 if it is getting at least 1,600-1,700 IU per day. Because Vitamin D3 is stored in the body overtime we can take it every three days for optimal absorption and health.

There has been argument in the field as to the difference between Vitamin D, Vitamin D3, and Vitamin D2. Recently, the Vitamin D Council stated that the naming is often misleading and desired to clear up consumers' questions. Vitamin D3 (cholecalciferol) is the natural form of Vitamin D that your body needs. Vitamin D2 is known as ergocalciferol. It is not normally found in the body and has no purpose in humans. Ergocalciferol is obtained from radiating yeast and is often the vitamin D that is in supplements. Vitamin D2 can be converted into calcitriol, but vitamin D3 is more than 3 times as effective as vitamin D2 in the body.

We only use Vitamin D3 from a natural source (sheep's wool) to provide our customers with the best available source of Vitamin D.

http://www.livestrong.com/article/322116-vitamin-d3-vs-vitamin-d/#ixzz1W3koQ9Xc