It appears that some vitamin brands are listing their products as Vegan, yet formulating them with vitamin D3 synthesized from Sheep's Lanolin. There is no Vegan source of vitamin D3, which is produced by chemical synthesis when animal fats called sterols are exposed to Ultraviolet light (UVB rays). D3, or cholecalciferol, is always made from animal fat. The other form, vitamin D2, or ergocalciferol, is from a Vegan source; though one has to watch out for animal gelatin stabilizers and microbeads in microencapsulated dry forms, especially. Vegan microencapsulation for dry forms of fat-soluble nutrients including beta-carotene and lutein was only perfected in mid-2005, so it is possible that some products made before then were mislabeled as Vegetarian if the company did not investigate its raw material sources carefully. (Many brands do not manufacture their own vitamin supplements, relying on contract manufacturers to make their outsourced formulas for them. In many cases, the brands do not normally have access to the full ingredient and finished product specifications of the actual manufacturer. This can lead to ignorance and errors when making label claims related to the presence or absence of allergens and animal products.) The D2 form is synthesized from plant sterols exposed to the same kind of light. Plant sterols, by the way, have an FDA-approved health claim that they "may reduce the risk of heart disease" and are considered healthy. http://www.fda.gov/Food/GuidanceComplianceRegulatoryInformation/GuidanceDocuments/FoodLabelingNutrition/FoodLabelingGuide/ucm064919.htm There is also a controversy over whether D3 is much better than D2. D3 is the form found in fish liver oils and is often added to fortify foods such as milk and orange juice. D3 is also the form that we synthesize in our own bodies when cholesterol (that animal sterol aforementioned) is exposed to UVB rays. D2 is likewise made by plants when their oils (plant sterols, or phytosterols) are exposed to UVB light. In modern studies, both forms are equally well absorbed and both are good at preventing rickets and maintaining bone mass. Both forms equally maintain the level of the active compound serum 25(OH)D3 levels. "Therefore, vitamin D2 is equally as effective as vitamin D3 in maintaining 25-hydroxyvitamin D status." http://www.sciencedaily.com/releases/2008/01/080102122306.htm It appears that D3 tests better than D2 in an occasional dosing schedule, like if you got it once a month from a doctor's office. But the assay is apparently flawed and is now known to not measure D2 very well, underestimating its circulating level. For everyday supplementation and fortification, both forms work equally well by all current measures. Some brands with "cultured" or "fermented" ingredients apparently believe that adding lanolin-sourced vitamin D3 to a yeast culture, then drying the whole thing and using it to make vitamins, somehow transmutes the animal fat form of the vitamin into a Vegan-friendly ingredient. They say that the yeast consumes the lanolin-derived vitamin and that the yeast is Vegan no matter what it is fed. But they present no evidence that yeast consumes vitamin D or changes it in any way. Quite the contrary; they brag about providing vitamin D3 – a known animal product - in a supposedly Vegan supplement. This indicates that they know that the form is not changed in any significant way by the yeast culture. One major brand, when asked by me only today, said that they do not disclose their D3 source for their vitamin labeled as Vegan because the source is both "irrelevant" and "proprietary". In other words, they won't tell us and we don't need to know. That pisses me off, pardon me for taking this apparent contempt for Vegans personally. I am not a Vegan but have been a vegetarian since 1972. I do not eat any type of flesh; avoiding not only all forms of meat but also animal broths, gelatin and leather. I scrutinize labels to assure that I am getting no animal products except for dairy, eggs, and honey. Now the Honest Nutritionist in me wants to sound the alarm that some companies are using animal products like gelatin and lanolin in their Vegan-claimed dietary supplements. Whether it's an honest (though sloppy) mistake or a deliberate attempt to have their cake and eat it too is hard to say for sure, but either way this is not fair to Vegans. I tend to fear the worst since they claim the supposedly superior and more popular D3 form in a product whose label also appeals to Vegans and Vegetarians who are being led to erroneously believe that there is now a Vegan-friendly source of D3. There isn't. It is just not true. We are being misled. D3 is not Vegan. D2 is, and is not a bad form as some try to claim. Some medical experts even want to routinely fortify the food supply with D3 because of the largely mythical superiority of that form; that would deprive all Vegetarians and Vegans of their right to avoid hidden animal products in our food. I believe that we have a fundamental right to select our diets based on individual religious, ethical, and cultural beliefs. It is wrong for a corporation to take that right away from us by incorrectly labeling their products that are marketed to Vegetarians and marked as Vegan. Mislabeled products are considered to be adulterated. Obviously, there is no safety issue here and it does not seem as if this matter has attracted much attention, as of yet. But these jokers have attracted my attention and I think that they deserve to get grassroots attention to their attempt to sell non-Vegetarian products to Vegetarians and Vegans. I am not naming names here but will not buy products made by any companies which suggest that animal-source D3 can ethically be sold to Vegans. If you are of the Vegetarian or Vegan persuasion, please check your product labels. If I see vitamin D3 in a product labeled as Vegetarian, I’d feel free to return it to the store as a mislabeled product and get my money back. Vote with your dollars and read product labels carefully before buying anything. If enough people do this, the companies with questionable products will have to deal with a lot of returns from unhappy customers and stores, combined with a drop in sales. Eventually, they will be forced to either correct their labels or change their formulas.