I was just responding to the prior poster.  There is no such thing as an "organic" vitamin D supplement.

I currently take 10,000 units of D3 per day.  Took 50,000 for several months but it caused my creatine levels to go over 2.0 which endangers the kidneys.  May return to that level for a while but anyway, have been at either 50,000 IUs of D or 10,000 IUs for at least a couple of years.

"What do you consider vitamin D3 made from fermented yeast to be? How about vitamin D3 made from mushrooms (such as the white button mushroom)? Whatever you call them, such food derived vitamin D is much superior to synthetic vitamin D."

What you are describing is vitamin D2 and does not occur naturally in the human body.  Vitamin D2 is not recommended for vitamin D deficiencies.

As you will note below vitamin D3 is derived from both lanolin (which is a natural oil produced by sheep and other fur bearing animals) and cod liver oil (another natural oil).  This form of D IS the same as the vitamin D that is formed in the body.  It is what is recommended for the vast majority of individuals who are deficient in vitamin D - a hormone.

So, your vitamin D2 is in no way "much superior to" vitamin D3 - which is not synthetic.  (Pharmaceutical vitamin D is synthetic but I doubt that anyone on the vitamin d forum uses it.)

As for "organic" material grown on yeast/spores - penicillin is just that so penicillin is organic!  Does that make it good?  When this antibiotic was first discovered and brought to the scientific community a world wide search was made for the "best" source and it turned out to be a rotten cantaloupe found in a retail market in Minnesota!  So whoopdie doo - penicillin is produced organically.

http://www.vitamindcouncil.org/about-vitamin-d/what-is-vitamin-d/what-is-vita...

Supplemental vitamin D

Supplemental vitamin D comes in two forms:

1. Vitamin D3 cholecalciferol (pronounced koh·luh·kal·SIF·uh·rawl).
2. Vitamin D2 ergocalciferol (pronounced er·goe·kal·SIF·e·role).

Vitamin D3

Vitamin D3 is real vitamin D, for it is the same substance as what is produced in human skin in response to sun exposure. Supplemental vitamin D3 is derived from either lanolin or cod liver oil extract and is the form of vitamin D that most effectively treats vitamin D deficiency.

Vitamin D2

Vitamin D2 is derived from fungal sources by activating ergosterol with ultraviolet light. It is not naturally present in the human body and may have actions within the body different to those of vitamin D3.

Although many doctors are still prescribing vitamin D2, vitamin D3 is the preferred form for treating deficiency and is what is recommended by the majority of the experts as well as the Vitamin D Council.

Pharmaceutical vitamin D

There are also prescription forms of vitamin D, such as synthetic calcitriol and vitamin D analogs. Vitamin D analogs are synthetic compounds based upon variations of the naturally-occurring vitamin D metabolites.

High dose calcitriol use has been known to increase risk of hypercalcemia. Vitamin D analogs are seen as a way to achieve the beneficial effects of calcitriol without this risk.

Pharmaceutical vitamin D should never be used to treat vitamin D deficiency.