evidence: "Only vitamin D3 comes from wool from sheep. Some brands use vitamin D2 which comes from non-animal sources and is different from the vitamin D humans can synthesize from sun exposure," he said.. "DSM Nutritional Products’ natural-source Vitamin D3 is sold in crystalline, oil and powder forms. It is derived from lanolin taken from the wool of healthy live sheep living in Australia and New Zealand. An October 2003 Note for Guidance, adopted by the Committee for Proprietary Medicinal Products and the Committee for Veterinary Medicinal Products, states that derivatives of wool and hair from ruminants, such as lanolin, are compliant for use as natural-source supplements provided the wool or hair is taken from healthy, live animals. [...] Amount of D3 in wool 600,000 pills of 5,000 IU each - Nov 2009 http://ask.metafilter.com/138220/Amount-of-D3-in-wool