The case against ergocalciferol (vitamin D2) as a vitamin supplement
The American Journal of Clinical Nutrition, Volume 84, Issue 4, 1 October 2006, Pages 694–697, https://doi.org/10.1093/ajcn/84.4.694
Lisa A Houghton Reinhold Vieth
- If you have a vitamin D prescription, be sure that it is for D3– June 2017
- Loading dose of Vitamin D2 REDUCED vitamin D blood in a third of the patients – Jan 2015
- Vitamin D2 from cooked mushroom added virtually no vitamin D to bloodstream - RCT July 2015
- Vitamin D reduces risk of cause specific death, unless it is D2 – meta-analysis BMJ April 2014
- Vitamin D3 associated with fewer psychotic episodes, D2 with more – July 2012
- Primates Nutrient Requirements – 2003 ALL primates need D3, not D2
- Vets no longer use D2 for mammals due to adverse affects
- Overview Vitamin D3 not D2
All life on the planet has been getting Vitamin D3 naturally for over 500 million years.
Before the use of skeletons
Vitamin D2 is avaiable in small amounts in only a few forms of mushrooms
~ verv very few animals have evolved a good way to use vitamin D2
 Download the PDF from Vitamin D Life
Supplemental vitamin D is available in 2 distinct forms: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Pharmacopoeias have officially regarded these 2 forms as equivalent and interchangeable, yet this presumption of equivalence is based on studies of rickets prevention in infants conducted 70 y ago. The emergence of 25-hydroxyvitamin D as a measure of vitamin D status provides an objective, quantitative measure of the biological response to vitamin D administration. As a result, vitamin D3 has proven to be the more potent form of vitamin D in all primate species, including humans. Despite an emerging body of evidence suggesting several plausible explanations for the greater bioefficacy of vitamin D3, the form of vitamin D used in major preparations of prescriptions in North America is vitamin D2. The case that vitamin D2 should no longer be considered equivalent to vitamin D3 is based on differences in their efficacy at raising serum 25-hydroxyvitamin D, diminished binding of vitamin D2 metabolites to vitamin D binding protein in plasma, and a nonphysiologic metabolism and shorter shelf life of vitamin D2.
Vitamin D2, or ergocalciferol, should not be regarded as a nutrient suitable for supplementation or fortification.