Vitamin D vs. D3: Key Differences, Benefits & Which You Need
Vitamin D is the umbrella term for a group of fat-soluble secosteroids that help your body absorb calcium. Vitamin D3—scientifically cholecalciferol—is the animal-derived form your skin makes from sunlight and the one most supplements use.
People grab a bottle labeled “Vitamin D,” see “D3” on the back, and wonder if they’re missing something. The confusion spikes when plant-based friends mention “D2,” making shoppers freeze in the pharmacy aisle.
Key Differences
Vitamin D2 (ergocalciferol) comes from yeast or mushrooms; D3 is sourced from lanolin or fish. D3 raises blood levels of active vitamin D more efficiently and lasts longer, so you need lower doses to reach the same target.
Which One Should You Choose?
Most adults should choose D3 unless they’re strict vegans—then a high-quality lichen-based D3 or a D2 supplement works. Check the label: if it says “cholecalciferol,” it’s D3, and that’s typically the better pick.
Is D2 ever better than D3?
Only for vegans avoiding lanolin or fish; otherwise D3 is superior for raising and maintaining blood levels.
Can I get enough Vitamin D from sunlight alone?
If you have year-round midday sun on bare skin, maybe. Office workers, darker skin tones, and high-latitude residents usually need a supplement.
How much D3 do I need daily?
600–2,000 IU covers most adults, but a blood test lets you and your doctor fine-tune the exact dose.