Before You Buy Vitamin D
What to look for (and what to avoid)
TL;DR
Get D3 (cholecalciferol), not D2. 2000-5000 IU daily for most adults. Take with fat for absorption. Get blood work to dial in your dose. K2 combo is useful but not essential.
Quick Checklist
What to Look For
87% less effective at raising blood levels than D3.
Unless prescribed for deficiency, weekly mega-doses are unnecessary.
D3 is fat-soluble. Needs fat to absorb properly.
Quality control varies wildly by manufacturer.
Both work equally well.
Better absorption than dry tablets.
Helps direct calcium to bones, not arteries.
Third-party verified potency.
Forms Ranked
| Form | Score | Best For | Notes |
|---|---|---|---|
| D3 Softgel (oil-based) | 10/10 | Most people | Best absorption, stable |
| D3 + K2 Combo | 10/10 | Bone health focus | K2 helps calcium go where it should |
| D3 Drops | 9/10 | Flexible dosing | Easy to adjust dose |
| D3 Dry Tablet | 6/10 | Budget option | Take with fatty meal |
| D2 (any form) | 3/10 | Vegans who can't find vegan D3 | Lichen D3 now exists, use that instead |
Dosing Guide
Is Vitamin D For You?
You Might Need It If...
- Anyone living above 37th parallel (limited sun)
- People with darker skin (need more sun exposure)
- Those who work indoors or wear sunscreen daily
- Elderly (skin produces less D with age)
- Overweight individuals (D gets stored in fat)
You Probably Don't Need It If...
- People with adequate sun exposure (and blood levels to prove it)
- Those with hypercalcemia or certain conditions
- Anyone with blood levels already above 60 ng/mL
Common Mistakes
D2 is prescription because of patents, not efficacy. D3 is better.
The Bottom Line
D3, not D2. 2000-5000 IU daily for most people. Take with fat. Get blood work annually to dial in your dose. D3+K2 combo is a nice bonus for bone health.
Learn More About Vitamin D
More Buying Guides
About this information: Our analysis of Vitamin D is based on peer-reviewed research from PubMed, ClinicalTrials.gov, and NIH databases. These statements have not been evaluated by the FDA. Supplements are not intended to diagnose, treat, cure, or prevent any disease.
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