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Medically reviewed by Dr. Sarah Mitchell, MD
Vitamin D3 vs D2: Which Form Should You Take?
Medical Disclaimer: This article is for educational purposes only and does not constitute medical advice. Always consult a healthcare professional before starting any supplement regimen.
Last updated: December 5, 2025. Medically reviewed by Dr. Sarah Mitchell, MD.
Quick Answer: Vitamin D3 (cholecalciferol) is the clear winner. It raises blood levels 2-3x more effectively than D2 and is the form your body naturally produces from sunlight. Always choose D3 over D2.
D3 vs D2 Comparison
| Factor | Vitamin D3 | Vitamin D2 |
|---|---|---|
| Source | Animal-based (lanolin, fish) | Plant-based (mushrooms, yeast) |
| Effectiveness | ★★★★★ 2-3x more effective | ★★☆☆☆ Less effective |
| Blood level increase | ★★★★★ Superior | ★★☆☆☆ Inferior |
| Duration in body | ★★★★★ Longer half-life | ★★☆☆☆ Shorter half-life |
| Research backing | ★★★★★ 100+ studies | ★★★☆☆ Fewer studies |
| Vegan | ❌ Usually not | ✅ Yes |
| Cost | $8-12/mo | $8-12/mo |
Why D3 Wins
A 2012 meta-analysis in Journal of Clinical Endocrinology & Metabolism (Tripkovic et al.) found D3 was 87% more effective than D2 at raising serum 25(OH)D levels.
Your skin produces D3 when exposed to UVB sunlight. D2 is produced by fungi and plants. Your body is designed to use D3.
When D2 Might Be Appropriate
- Vegan preference: D2 is plant-derived (though vegan D3 from lichen exists)
- Prescription: Some doctors prescribe high-dose D2 (50,000 IU ergocalciferol)
- Mushroom-based: UV-exposed mushrooms provide D2
Our Recommendation
Take Vitamin D3. Look for:
- D3 (cholecalciferol) — NOT D2
- With K2 (MK-7) for calcium direction
- In oil-based softgels (better absorption than dry tablets)
- Third-party tested (USP, NSF, or ConsumerLab)
Dosage: 2000-5000 IU daily (test blood levels; target 40-60 ng/mL).
Related: Best Vitamin D Supplements