Vitamin D3 is not the same as D2

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 the sheep 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 (Owings E. 2009), 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 of 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. When 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 in believe about 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 the 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:



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 was 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 preferably 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 knew 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!

We need to take action our selves in this matter. So instead of going in to the pharmacy and giving the prescription away for some D2 in return go to the supplement isle and pick up some REAL Vitamin D3 supplement over the counter!!! You don’t have to look for long to find a Vitamin D3 supplement: GNC has it, CVS has it, RiteAide has it… and your local grocery store probably has it too. Don’t get your Vitamin D from a prescription – it requires roughly twice to 250% of D2 to match the effect of D3 (Trang H. et al 1998; Armas LA et al 2004; Harris SS et al 2002).

Most Vitamin D3 recommend a daily dose of 1000 IU, I would increase it to 5000 IU a day for an adult. More if you are overweight, have Type II Diabetes, have high blood pressure, and are in general deficient in Vitamin D levels.