Vitamin D3 Bioavailability

My level of Vitamin D is 11.6. My physician wants to prescribe Drisdol (D2) 50,000 IU. After reading your information on Vitamin D2 vs D3, I asked the pharmacist a few questions about D2 bioavailability.

He said that at 50,000 IU of D2 there is better bioavailability by the body. I wonder if they have to give 50,000 IU b/c the body doesn't absorb as much, and if I were to take Vitamin D3...would I take a lesser IU b/c it is absorbed better (according to your source of information).

Can you clarify what you know about this, and also send me a reference to a few studies that I can see your source of information. Have's there been a particular brand of D3 that has been studied to be effective?

The only symptoms that I suppose could be related to this vit D deficiency is some chronic pain in my neck vertebrae...but I have some disc problems there. I'm not sure if that pain is related to vit D deficiency. I'm surprised my vit D level is so low b/c I don't feel like I experience any of the symptoms you list.

Comments for Vitamin D3 Bioavailability

Click here to add your own comments

The Resources are right on that page...
by: Kerri Knox, RN- The Immune Queen!


I'm glad that you found out your vitamin d level is so low BEFORE you have a bunch of the symptoms that I mentioned. If you read my page on Symptoms of Vitamin D Deficiency, you'll see that I mention that there are very often NOT any symptoms until one gets:

Breast Cancer

Heart Failure

Multiple Sclerosis

or other problems. Those ARE the symptoms of long term vitamin d deficiency. And that's why it's so important to have levels checked because that would really be crappy to have your first symptom of Vitamin D Deficiency be Breast Cancer!

And as it is, your neck pain very well could be JUST due to Vitamin D Deficiency. There is a doctor named Dr. Sarno who EFFECTIVELY treats chronic pain in a unique way and says that disk problems are often NOT related to the pain that you are experiencing and it is VERY OFTEN simply coincidental- and that people who have neck or back pain have no higher incidence of disk problem than do people WITHOUT pain- just nobody did CT scans and MRI's on people WITHOUT pain until Dr. Sarno was the impetus to do studies on people with these problems.

So, your neck pain may have ABSOLUTELY NOTHING to do with your disk problems. EVERYONE has disk problems!!

And as far as my resources, my resources are right there on the Vitamin D3 Page. Do you see where the multiple quotes from researchers in studies are, and the reference in parentheses next to them. Those ARE my resources!!

But if you also go to the Prescription Vitamin D page, there is an underlined link to the study The Case Against Ergocalciferol as a Vitamin D Supplement.

Kerri Knox RN Immune Health Queen

Kerri Knox, RN- The Immune System Queen
Functional Medicine Practitioner
Immune System

Click here to add your own comments

Return to Question About Vitamin D3 vs Vitamin D2?.

Enjoy this page? Please pay it forward. Here's how...

Would you prefer to share this page with others by linking to it?

  1. Click on the HTML link code below.
  2. Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment, your Facebook account, or anywhere that someone would find this page valuable.


Search this Site
Custom Search


Vitamin D Fact Sheet
Free Vitamin D Fact Sheet by Getting
My Newsletter