Overview Vitamin D3 not D2
Vitamin D2 has been known for a long time to not be as good as vitamin D3
VitaminD2 was the first to be discovered and, until 2011, was the only one that most doctors could prescribe
The D3 form has been known for many decades, but the medical profession has not yet adapted - after all, only 12,000 papers on D3 asof Oct 2023.
Several recent studies have shown that vitamin D2 actually reduces the levels of D3 in the blood
AND, worse still, D2 actually INCREASES a health problem , instead of reducing it, the way vitamin D3 does
Notes:
Some multivitamins and milk/food fortifications still use D2, but in such low quantities that it can be ignored.
Some people buy D2 because it is vegan, being unaware that there are vegan forms of D3
All items in D3 vs D2 items
Vitamin D2 actually decreased vitamin D3 levels – RCT Nov 2012
Vitamin D3 increased and Vitamin D2 decreased the D3 serum levels – RCT Sept 2013
Vitamin D2 decreased blood levels of Vitamin D3 by 12 ng – RCT July 2012
Vitamin D3 is much better than D2, especially if not taken daily – meta-analysis June 2012
MS worse with Vitamin D2 - Oct 2011 high dose of D2 resulted in worse MS than low dose
Chance of a fall decreased with vitamin D3 but increased with D2 – Oct 2011
10 million IU of vitamin D3 for cows was great unless had vitamin D2 – July 2011
Hemodialysis not helped by weekly vitamin D2 – RCT April 2015
Following large doses of vitamin D2, Vitamin D3 doses were unable to achieve sufficiency – Jan 2014
Vitamin D2 decreased vitamin D3 levels in the blood – Feb 2011
Vitamin D2 loading doses did not increase, and may have decreased blood levels– June 2011
Vitamin D3 for Vegans - Oct 2011 lichen, etc.
Primates Nutrient Requirements – 2003 ALL primates need D3, not D2
Vitamin D3 but not D2 reduces mortality – Cochrane meta-analysis July 2011
- 6% relative risk REDUCTION of mortality when supplementing with vitamin D3 ;
- 2% relative risk INCREASE of mortality when supplementing with vitamin D2
Vitamin D from mushroom or supplements decreased vitamin D3 in the body – June 2012
Vitamin D3 much better than D2 for loading doses– meta-analysis May 2012
- Not much difference between D3 and D2 for daily doses?
Vitamin D2 did not help Lupus (no surprise, D2 was given weekly) – June 2013
Cooked mushrooms (Vitamin D2) did not increase vitamin D serum levels – Aug 2014
Vitamin D3 far better than D2 at raising infant vitamin D blood levels – Dec 2012
- Vets no longer use D2 Vitamin D2 should not be used as a Vitamin supplement for any mammal – Oct 2006
Graphs of diseases vs vitamin D levels - and D3 vs D2- April 2011 which has the following
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Far better response to D3 than D2
Response to 20,000 IU vitamin D3 extra per week

Most > 20ng and some > 40ng
Response to 20,000 IU of vitamin D2 per week (im = inter-muscular injection)

Very few got to 40ng
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The 2006 study can be read at Vitamin D2 should not be used as a Vitamin supplement for any mammal – Oct 2006
D2 decreases D3 (50,000 IU D2 every 14 days) - June 2012
TREATMENT WITH 50000 IU VITAMIN D 2 EVERY OTHER WEEK AND EFFECT ON SERUM 25-HYDROXYVITAMIN D2. .

📄 Download the PDF from VitaminDWiki
Irradiated mushrooms decreased Vitamin D3 levels by 40% - Nov 2020
Assessing the impact of a mushroom-derived food ingredient on vitamin D levels in healthy volunteers
1000 IU D2 daily from irradiated Mushrooms for 12 weeks
📄 Download the PDF from VitaminDWiki
11+ VitaminDWiki pages with MUSHROOM(S) in the title
This list is automatcially updated
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See also VitaminDWiki
Doctors now able to prescribe vitamin D3 as of March 2012
5000 IU vitamin D3 added daily to bread raised blood levels to 50 ng – 2009
See also web
Effectiveness of vitamin D2 compared with vitamin D3 replacement therapy in a primary healthcare setting: a retrospective cohort study - Aug 2022 DOI: 10.5339/qmj.2022.35
Better response by D3 to injection or tablet, even when giving 2X more D2 than D3
600,000 IU D2 for 300,000 IU D3 - then measure 12 weeks later
The case against ergocalciferol (vitamin D2) as a vitamin supplement - Veith 2006 📄 PDF
D2 vs. D3 - What is the Difference? Grassroots Health, March 2019
- Avoid D2, tell doctor of better D3
Prescription Strength (D2) not as good as D3 Easy Immune Health
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- 1000 IU of D3, 1000 IU of D2, placebo: taken daily in RCT lasting 25 weeks into the winter.
- Serum levels DECREASED in those getting the 1000 IU daily of D2, compared to PLACEBO
- Comparison of vitamin D2 and vitamin D3 supplementation in increasing serum 25-hydroxyvitamin D status: a systematic review and meta-analysis
- 2 pages, AJCN Oct 2012 - unfortunately it is behind a paywall
50,000 IU Vitamin D2 weekly did not help insuline sensitivity Oct 2012
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- In the group receiving vitamin D2. . . . 25(OH)D3 concentration fell from 36.4 ± 13.3 nmol/L at baseline to 16.6 ± 6.3 nmol/L after 8 weeks (P < .01)
- yet again, D2 lowers the level of D3 in the blood
Higher 25(OH)D2 Is Associated With Lower 25(OH)D3 and 1,25(OH)2D3. May 2014
Research shows taking vitamin D2 is a poor choice for athletes Jan 2014
- six weeks of vitamin D2 - NASCAR pit crew athletes and the effects on exercise-induced muscle damage and delayed onset of muscle soreness
- 3800 IU D2 daily decreased D3 levels and increased muscle damage
- Differential responses to vitamin D2 and vitamin D3 are associated with variations in free 25-hydroxyvitamin D July 2016
- In mice the difference between blood response to D2 and D3 is due to differences in response by Vitamin D binding protein
Higher 25(OH)D2 is associated with lower 25(OH)D3 and 1,25(OH)2D3 Aug 2014
here are some images of D2 to stay away from

See also PDFs at the bottom of this page
Changes in circulating 25-hydroxyvitamin d according to vitamin D binding protein genotypes after vitamin D3 or D2 supplementation April 2013
Yet again: D2 reduces the levels of D3 in the blood. Also, D2 does not turn on genes.
Vitamin D2 Supplementation Amplifies Eccentric Exercise-Induced Muscle Damage in NASCAR Pit Crew Athletes : Jan 2014
Vitamin D2 made muscle damage WORSE. 3,800 IU D2 from Portobello mushroom powder
Vitamin D Council post on this item
short url for the page = http://is.gd/vitd3d2