Why vitamin D2 instead of D3?

[SarahVaughter]

Hi Sarah,

I just ordered your kit and feel that your site is very professional and thorough.  I do have a question:  why are you using synthetic vitamin D2 instead of D3.  I only take D3 internally due to all of the articles I have read about the efficacy of D3 over D2.  Thank you.

I read the articles too. AFAIK, they are based on one single study:

https://http://jcem.endojournals.org/cgi/content/full/89/11/5387      

.. which is "disproved" in this study:

https://http://www.medscape.com/viewarticle/573613  

My take on it: There is no hard evidence that D3 is better than D2. D2 has worked very well in the past and as soon as we find anything better or are advised of such (you're more than welcome to offer suggestions), we'll switch to it.