Vitamin D3 vs Vitamin D2

Vitamin D3 (cholecalciferol) and Vitamin D2 (ergocalciferol) are the two primary forms of Vitamin D. However, their biological source and absorption longevity differ substantially.

Detailed Comparison

FeatureVitamin D3 (Cholecalciferol)Vitamin D2 (Ergocalciferol)
SourceLanolin (sheep wool), Lichen (vegan)UV-irradiated yeast and mushrooms
Serum RetentionLong-lasting (weeks)Short-lived (days)
Biological PotencySuperior (High affinity to binding proteins)Inferior
Preferred By MDsYes (Preferred in clinical guidelines)Rarely (Only prescribed in legacy high-dose D2 packets)

Key Benefits

Vitamin D3

  • +Vitamin D3 binds tightly to vitamin D receptors and transport proteins in human blood.
  • +Vitamin D2 is cleared by the liver and kidneys much faster, requiring more frequent dosing.

Our Recommendation

Always choose Vitamin D3. It is the natural hormone form synthesized by the body and is clinically proven to keep systemic vitamin D levels elevated much longer than D2.

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