Vitamin D: which form, what each one does, and the dose that worked
Vitamin D comes in many forms, and what it does depends on the form. Every result below names the form it came from. Pick the form you take to see its own studies, products and what the biohackers say about it. This page is educational, not medical advice.
What it does, by goalMembersThe top 5 of 18 goals
7 of these 196 human studies gave vitamin d by drip or injection, not by mouth.
| Goal | What the studies show | Studies | Dose that worked |
|---|---|---|---|
| Improved in studies D3: 8 of 18 improved, 5 no effect · D2: 1 study, no effect | 19 | D3 600 IU | |
| Improved in studies D3: 5 of 15 improved, 6 no effect · Calcifediol: 1 of 1 improved · D2: 1 study, no clear result · 2 by drip, injection or inhaler | 17 | D3 100 IU | |
| Improved in studies D3: 6 of 10 improved, 2 no effect · D2: 1 study, no effect | 11 | D3 0.3 mcg | |
| Improved in studies D3: 5 of 28 improved, 11 no effect · D2: 2, both no effect | 30 | D3 10,000 IU | |
| Improved in studies D3: 5 of 26 improved, 14 no effect · Calcifediol: 1 study, no effect · D2: 1 study, no clear result · 1 by drip, injection or inhaler | 28 | D3 1,200 IU | |
| Improved in studies D3: 4 of 10 improved, 3 no effect · D2: 1 study, no effect | 11 | D3 1,000 IU | |
| Improved in studies D3: 4 of 10 improved, 1 no effect | 10 | D3 2,000 IU | |
| Improved in studies D3: 2 of 24 improved, 15 no effect · Calcifediol: 1 of 1 improved · D2: 1 study, no clear result · 2 by drip, injection or inhaler | 26 | D3 4,000 IU · calcifediol 5,000 IU | |
| Improved in studies D3: 3 of 9 improved, 3 no effect · D2: 1 study, no clear result | 10 | – | |
| Improved in studies D3: 3 of 8 improved, 1 no effect · 2 by drip, injection or inhaler | 8 | – | |
| Improved in studies D2: 1 of 2 improved · D3: 1 of 2 improved · 1 by drip, injection or inhaler | 4 | D2 50,000 IU · D3 1,600 IU | |
| Improved in studies D3: 2 of 3 improved · 1 by drip, injection or inhaler | 3 | – | |
| Improved in studies D3: 1 of 3 improved, 2 no effect · D2: 1 study, no clear result | 4 | D3 1,200 IU | |
| Too few studies D3: 1 of 17 improved, 11 no effect · D2: 1 study, no effect | 18 | – | |
| Too few studies D3: 1 study, no clear result | 1 | – | |
| No effect in studies D3: 4 of 10 improved, 2 no effect | 10 | D3 2,000 IU | |
| No effect in studies D3: 1 of 5 improved, 1 no effect · D2: 1 of 3 improved, 1 no effect | 8 | D3 1,000 IU · D2 1,000 IU | |
| No effect in studies D3: 2 of 6 improved, 3 no effect | 6 | D3 2,000 IU |
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Products – highest ranked firstMembersThe top 3 of 31
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Dose and safetyThe dose that worked and the upper limit
The doses that worked, by form, in the studies taken by mouth: D3 100 to 200,000 IU, D2 1,000 to 50,000 IU, calcifediol 5,000 IU a day.
The upper limit for adults is 100 mcg of vitamin d a day; above it, members see a note and are told they can take less.
Biohacker panelMembersWhich forms of vitamin d our 10 biohackers name
Questions people askMembersAnswered from the figures on this page
Which form of vitamin d is best?
Answer for members.
How much vitamin d a day?
Answer for members.
Can I take vitamin d with my meds?
Answer for members.
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Educational, not medical advice. Figures come from the human studies on PubMed we have graded; a study counts for a form when it names the form it used. Updated as new studies arrive. How we grade →