Vitamin D vs Vitamin D3: What's the Difference?

Vitamin D vs Vitamin D3 — Vitamin D2 (ergocalciferol) is derived from plants and yeast and is the form found in most prescription vitamin D. Vitamin D3 (cholecalciferol) is the form your skin produces from sunlight and is derived from lanolin or fish oil in supplements. D3 is more effective at raising and maintaining blood vitamin D levels — clinical research shows D3 is approximately 87% more potent than D2 at the same dose.

Quick Comparison

Feature	Vitamin D2 (Ergocalciferol)	Vitamin D3 (Cholecalciferol)
Best For	Plant-derived, prescription form	Animal-derived, more bioavailable
When to Use	Only when prescribed by a clinician (typically high-dose intermittent dosing).	Daily supplementation, especially for those with limited sun exposure, deficiency, or concerns about bone, immune, or mood health. Most adults benefit from 2,000–5,000 IU daily.

Vitamin D2 (Ergocalciferol)

• Found in plants, fungi, and prescription Rx vitamin D
• Less effective at raising blood 25(OH)D levels
• Often used for prescription megadoses (50,000 IU)
• Vegan-suitable when sourced from yeast

Vitamin D3 (Cholecalciferol)

• Same form your body makes from sunlight
• More effective at maintaining blood levels
• Standard form in over-the-counter supplements
• Sourced from lanolin or lichen (vegan options exist)

Which Should You Choose?

Choose Vitamin D2 (Ergocalciferol) if: Only when prescribed by a clinician (typically high-dose intermittent dosing).

Choose Vitamin D3 (Cholecalciferol) if: Daily supplementation, especially for those with limited sun exposure, deficiency, or concerns about bone, immune, or mood health. Most adults benefit from 2,000–5,000 IU daily.

The Bottom Line

Vitamin D2 (ergocalciferol) is derived from plants and yeast and is the form found in most prescription vitamin D. Vitamin D3 (cholecalciferol) is the form your skin produces from sunlight and is derived from lanolin or fish oil in supplements. D3 is more effective at raising and maintaining blood vitamin D levels — clinical research shows D3 is approximately 87% more potent than D2 at the same dose. Both forms are well-tolerated and effective for their intended use. Many practitioners recommend rotating or combining based on your changing needs.

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