D2 and D3 are two different things 3. September 2009 William Davis (15) Helena posted this instructive comment in response to the Heart Scan Blog post, Weight loss and vitamin D. It illustrates the confusion common among physicians and pharmacists on the differences between D2 and D3. (Edited slightly for clarity.)Not many weeks ago a colleague of mine (let’s call him Eric) asked me if I knew the difference between D2 and D3 and I told Eric that D2 comes from irradiated mushrooms and D3 comes from wool. In other words, D3 is the same kind of vitamin as humans get from the sun. Humans just don’t get enough and we can’t produce it on our own, like the sheep can. (D3 is natural for humans, D2 is not.)After telling Eric this, he asked me how he would know what he is taking and I gave him the medical definitions of them both (D2 = Ergocalciferol; D3 = Cholecaliciferol). Since I was aware that he had gotten his Vitamin D by prescription, I told him “I am 99.9% sure that you are taking D2, but I would be thrilled to find out I am wrong.” Eric called his pharmacy right away and got the answer I was expecting: ergocalciferol. On confronting the person Eric was talking to, the answer he got back was that Ergocalciferol is the only Vitamin D they are giving out. A week later, Eric had a new appointment with his doctor and decided to ask him about the D2/D3 issue. The doctor said he knew that there was a difference in them both, but could not say what, not even the basic facts I mentioned above. But the doctor stamped a post-it with what he had sent to the pharmacy just to show Eric. “Vitamin D3; 50,000IU tab” is what the stamp said. Eric, off course, got confused and was starting to believe that the pharmacy had made a mistake by giving him Ergocalciferol (D2) since the doctor had given him D3, or at least that is what was stamped on the little note he had. Today, after getting a refill of his Vitamin D he also got and kept all his paperwork that came along with it. Still believing that stamp the doctor had given Eric earlier, he asked me to double and triple check that my definition of D2 and D3 was correct. I did, just for my own sanity, and I was still right. One of the sheets Eric brought me today was the “Patient Education Monograph” sheet stating the drugs and how to use it and so on. The thing that jumped out the most to me was this: Generic Name: Vitamin D – OralCommon Brand name(s): Drisdol, Maximum D3Identification: PA140 Green Oval CapsuleThis is the Drug Eric was given: Vitamin D 1.25 MG softgel; Generic name: ErgocalciferolMy researching mind went into high concentration mood and I started to dig. And this is what I found: The brand name Drisdol is Ergocalciferol (D2), not D3. The Brand name Maximum D3 seems to be hard to find out there in cyber space as a brand name. But the ones I found that were called Maximum D3 seems to be the real stuff, however none of them required a prescription. When trying to find out through the identification number on the pills (PA140) I now know for sure that Eric is taking Vitamin D2 and not the preferred Vitamin D3. The brand name, Drisdol, had the identification W on one side and D92 on the other, but it is still Ergocalciferol. The only conclusion I can draw from all this is that the medical industry does not know or care about the difference in D2 and D3 – it is all same to them. And as long as the pharmacies only give out D2 it does not matter what the doctor prescribe anyway. I know that people are most likely to be prescribed a D2 pill than to be told to buy over-the-counter D3. But it was almost heart breaking to see the letter D and number 3 right next to the drug Drisdol, as we know is a D2 vitamin. It just didn’t make sense to me that they can be labeled as the same type of medication, when we know it is not! Incredible.Why prescribe plant form D2 when you can get perfectly reliable, safe, effective D3--the human form, at the health food store for about $6? Once again, it's the peculiar false bias of physicians and pharmacists: If it's prescription, it must be good; if it comes from a health food store, it must be bogus. Humans need human vitamin D. Plain and simple.For more on the D2 vs. D3 issue, see the Heart Scan Post, The case against vitamin D2.