How much better is D3 than D2?

A meta-analysis found D3 supplementation raised serum 25(OH)D levels approximately 15.69 nmol/L higher than D2 at equivalent doses. The gap is most notable when supplementing consistently over weeks to months.

Is vitamin D2 effective at all?

Yes. D2 (ergocalciferol) is bioactive and can raise serum 25(OH)D levels. It is simply less efficient than D3 at the same dose, requiring higher amounts to achieve comparable serum elevation.

Can vegans take vitamin D3?

Standard D3 is derived from lanolin (sheep's wool). However, lichen-sourced D3 is a vegan alternative with equivalent efficacy. It is available in supplement form but typically at a higher cost than lanolin-derived D3.

Moderate Evidence

Vitamin D3 vs D2: Which Form Raises Levels More Effectively?

Vitamin D3 (cholecalciferol) raises 25(OH)D serum levels approximately 15.69 nmol/L higher than D2 (ergocalciferol) at equivalent doses in meta-analysis data.

Updated 2026 · Reviewed by Dr. Brennan Commerford, D.C.

Our Recommendation

Vitamin D3

Meta-analyses consistently show D3 raises and maintains serum 25(OH)D levels more effectively than D2 at equivalent doses.

Vitamin D3 (Cholecalciferol) vs Vitamin D2 (Ergocalciferol)

FormulaForge Choice

Vitamin D3 (Cholecalciferol)

Pros

+Raises serum 25(OH)D levels ~15.69 nmol/L higher than D2 in meta-analysis data
+The form produced naturally in human skin from sunlight exposure
+Longer duration of action — maintains serum levels more effectively

Cons

-Animal-derived sourcing (lanolin); vegan D3 from lichen is available but higher cost
-Requires co-administration of vitamin K2 at higher doses per standard practice

Best For

Most individuals seeking to support serum 25(OH)D levels and bone, immune, and mood-related structure/function.

S1 bioavailability tier — superior serum elevation vs D2

Vegan Option

Vitamin D2 (Ergocalciferol)

Pros

+Plant/fungal-derived — suitable for vegans without lichen-sourced D3
+Lower cost per unit
+Still bioactive and can raise 25(OH)D levels

Cons

-Raises serum levels less effectively than D3 at equivalent doses
-Shorter half-life — less sustained elevation between doses
-Less preferred by most clinical guidelines

Best For

Vegans who cannot access lichen-derived D3 and need a plant-sourced vitamin D option.

S2 bioavailability tier — effective but less potent than D3

Frequently Asked Questions

How much better is D3 than D2?: A meta-analysis found D3 supplementation raised serum 25(OH)D levels approximately 15.69 nmol/L higher than D2 at equivalent doses. The gap is most notable when supplementing consistently over weeks to months.
Is vitamin D2 effective at all?: Yes. D2 (ergocalciferol) is bioactive and can raise serum 25(OH)D levels. It is simply less efficient than D3 at the same dose, requiring higher amounts to achieve comparable serum elevation.
Can vegans take vitamin D3?: Standard D3 is derived from lanolin (sheep's wool). However, lichen-sourced D3 is a vegan alternative with equivalent efficacy. It is available in supplement form but typically at a higher cost than lanolin-derived D3.

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Related Resources

D3 Raises Serum Levels 16 nmol/L Higher Than D2 — Here's Why

Meta-analyses show D3 sustains serum 25(OH)D longer and more effectively. D2 is available for vegans and costs less. Our guide covers both forms, dosing by lab status, and cofactor timing.

See the D3 Research

FormulaForge formulates and sells supplements containing the ingredients discussed on this page. Our formulary recommendations are based on peer-reviewed bioavailability research. All cited studies are independently verifiable.