D2 and D3 are two different things

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 – Oral
Common Brand name(s): Drisdol, Maximum D3
Identification: PA140 Green Oval Capsule

This is the Drug Eric was given: Vitamin D 1.25 MG softgel; Generic name: Ergocalciferol

My 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!


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.

Comments (15) -

  • Low Cholesterol Foods

    9/3/2009 2:00:00 AM |

    [...]Low Cholesterol Foods. When you first learned that your cholesterol level is too high, you might start to imagine the illnesses you will have to suffer if you cannot reduce the cholesterol level in your blood[...]

  • mongander

    9/3/2009 3:28:10 AM |

    I am privileged to be friends with a famed media doctor and he acknowledges the superiority of D3 over D2, however my friend chooses to get his vitamin D directly from the Florida sun.  When he travels in the north in the winter, he supplements with D3.  Although age 75, he's a very active athlete and  says he suffers from muscle injuries when he's vit D deficient.

  • Ross

    9/3/2009 7:38:35 AM |

    Yeah, I couldn't convince my MD brother-in-law that D3 was superior to D2, especially since D2 was the prescription form (and therefore likely to be the "special" type).

  • Ross

    9/3/2009 7:54:38 AM |

    Oh, and the Low Cholesterol Foods link in the first comment is pretty much 100% nonsense, as I've learned from Dr. Davis and this blog.

  • TedHutchinson

    9/3/2009 10:29:26 AM |

    Just in case anyone thinks this is unbelievable here's the evidence.
    Drisdol Oral VITAMIN D - ORAL
    BRAND NAME(S): Drisdol, Maximum D3
    under the Profession Information tab we find Brand Name: Drisdol Generic Name: Ergocalciferol Capsules

    The situation is much the same in the UK. There is no form of stand alone presciption vitamin d3.
    There are combination products with calcium but clearly those are not suitable for someone just wanting to raise Vitamin D3 levels.
    Generally Vitamin D is referred to as calciferol. Doctors assume this is cholecalciferol and swear blind they only prescribe D3 however, in practice in the UK Cholecalciferol D3 as a stand alone product for vitamin D repletion simply isn't available as a licensed prescribable product.
    UK residents who want to guarantee they are getting Cholecalciferol are obliged to import from USA online discount providers.
    As you can buy a years supply of 360 x 5000iu softgels for $14.98 (less than £10) it really isn't worth risking getting vitamin d on prescription, even if you don't pay for your prescription.

  • Anonymous

    9/3/2009 10:42:01 AM |

    Dr Davis,

    Another good post.

    I think you are being somewhat generous in your conclusion.  I suspect the medical industry does know the difference between D2 and D3 and that the pharmaceutical companies are deliberately muddying the waters.  The simple fact is that D2, though less effective, is more profitable.  Its the same with prescription fish oils.  

    Its desperately sad but until such time as there is a wholesle change in the approach to health, towards prevention rather than cure, and towards quality of life, the best that most people can do is to educate themselves, always be suspicious of vested interests and the profit motive, and to seek focus upon quality in preference to qunatity across the spectrum of their lifestyle activities: food consumed, exercise, rest and sleep. That could probably extend to relationships and education as well.

    I really appreciate your focus on wheat elimination.  

    One area I would like to see discussed more is the health of the liver and its relationship to insulin resistance, appetite control, weight regulation and absorbtion of minerals and vitamins.  It strikes me that the liver is another potential canary in the coalmine, and is often overlooked by the mainstream medical profession - perhaps partly because there are few effective tratment protocols available to primary care doctors.  Indeed most drugs have the potential to damage the liver -not least of which being statins.

    Thanks for your regular posts - its always a good and provocative read.

    Paul Anderson.

  • Richard A.

    9/3/2009 7:46:11 PM |

    From drugstore.com
    Drisdol - 50000unit Capsules
    Quantity 50 capsules $109.98

    From iherb.com
    Healthy Origins, Vitamin D3, 5,000 IU, 360 Softgels $14.98

    One 50,000unit Drisdol cap costs $2.20.
    Ten 5,000iu Healthy Origins softgels costs $0.42.

    The Healthy Origins is 81% cheaper than Drisdol.

  • Anonymous

    9/3/2009 9:35:34 PM |

    A huge part of the problem is that much of industry/government does not want to get involved with the vegan/vegetarian community who demands D2 and does not want D3.  Dairy can be supplemented with D3 because it is a known animal product. But we can expect non animal products to contain D2 and not D3.  I think they know the difference, but they just do not want to have to deal with two versions of vitamin D.

    It's sort of like as more salt is kosher, so many are not getting the iodine they need because there is a group who demands kosher salt which cannot have any additives.  Tallow and lard have similar considerations.


  • moblogs

    9/4/2009 9:34:50 AM |

    You can get D3 on prescription in the UK.
    However, it's only in liquid form (which has a short expiry date) and only from hospital pharmacies as it's 'unlicensed medicine' on the NHS.

    It's a joke.

  • Hannes

    9/4/2009 4:11:32 PM |

    Does anyone know of a site that sells vitamin D and ships it to Estonia? I have been looking around a lot, but couldn't find any.

    They don't sell it in the drug store here. The best they have is 7.5 microgram tablets, which is ridiculous. I would really appreciate if I would be able to get it from somewhere, as I am sure you guys all know how important it is, especially in a northern country like mine!

  • Anonymous

    9/8/2009 9:52:09 PM |

    The above mentioned Maximum D3 is a pharmaceutical quality D3 recommended mostly by bone/endocrinology clinics and some other physicians.  It can be found at vitD3.com, as can links to several articles on D2 vs D3.

    It is NOT the same as Drisdol.

    The 10,000 IU capsule taken weekly will achieve blood levels comparable to sun exposed persons, because it is in a form that is stable and well absorbed.

  • simmy

    9/25/2009 7:43:41 PM |

    Speaking as a pharmacist: no, it's not my peculiar bias. There's only one vitamin D product in my _pharmacy_, and that's 50k-unit D2/ergocalciferol, because that is the only Rx-only oral vitamin D product in the US, barring calcitriol.

    In my experience most MDs and NDs writing for vitamin D don't understand the difference. I see plenty of 50k unit/week scripts written for D3, and I always call to clarify, because I am happy to pull D3 off the shelf on the floor. D2 is a cheap drug for which the insurance reimbursement is barely worth the time I have to spend on it.

    A few months ago I had a doc call me about a patient who couldn't swallow solid oral dose forms, and the doc wanted me to compound ergocalciferol drops. "Are you serious?" I said. "Give him D3 drops. The only reason to give D2 is convenience and insurance coverage, and you threw those out when you said 'compound'."

  • buy jeans

    11/3/2010 10:43:33 PM |

    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.

  • Jack C

    11/17/2010 11:22:41 PM |

    My wife and i had the same experience described by Helena.

    We had our D3 checked using finger prick test from the Vitamin D Council and my wife's D3 was low. Her physician wrote a prescription for D3 and we had it filled at the pharmacy for 50,000 IU of Drisdol Maximum D3.

    The physician commented that only the prescription D3 was any good. I told her that my D3 level was just fine (51 ng/ml)taking cod liver oil and Ddrops.

    Subsequently my wife had her vitamin D level checked and the results came back showing she had 18 ng/ml D3 and 14 ng/ml D2, for total of 32. That is the first clue that we had been deceived by the pharmacy and drug company.

    It is incredible that the drug companies and pharmacies engage in such deception.

    Jack C.

    Jack C.

  • Helena

    8/24/2012 6:59:03 PM |

    I should mention now.. a little later than when this post was written.. That Eric was taking his D2 50,000 IU supplements for 3 months without anything happening to his Vitamin-D levels. I got him to try over-the-counter D3 and his levels are now where they need to be... His doctor's reaction... have no idea.. He probably thinks it is a delayed effect of the D2.. but I am not sure.
    - Helena