I started at 20-22 over 1.5 years ago...I have been working on this for a while with both D3 and D2. Neither worked at first. I gained small amounts at a time...up to 24 and then most recently to 26 (before I did this last course of D2 after Rifaximin). I may not be grossly deficient in terms of others that come here....but I am significantly deficient for someone with an autoimmune disease. I'm not worried that I don't make any D...as obviously, I do. I just need to get a good healthy level and then maintain it.

If the body is functioning properly, then I don't see why we should have to supplement at all...for ANY substance. But of course, we don't all function at peak performance and don't eat all the foods necessary for obtaining all the proper nutrients. We do the best we can and supplement where needed.

Rx version of D2 is not meant to be taken all the time...but of course we need D every day. There is no way to know whether I am able to maintain a healthy level on my own (with foods, sun, etc) unless I see what the level does over the next 3 months or so. It will also tell me whether the D2 stays in the system. If i start to drop, then I will likely take small amounts of D3 to maintain a healthy level for my autoimmune condition. It's just nice to know that D2 will work for me (and maybe for others, if they have proper absorption).