Cholecalciferol vs Ergocalciferol: what is the difference?

How they differ

These are vitamin D3 and D2 and they differ in a side chain, C27H44O against C28H44O. D3 is what human skin makes when ultraviolet B light hits 7-dehydrocholesterol, and it is also what comes from fish and lanolin. D2 is the fungal and plant version, made when the same light hits ergosterol, which is why ultraviolet-treated mushrooms are sold as vitamin D enhanced. Both are converted by the liver and kidney into the active hormone, but D3 raises and holds blood levels of the storage form more effectively than D2 does, which is the practical reason most supplements now use D3. D2 remains the vegan option and the historical form used to fortify milk.

Side by side

Structural similarity 0.67 of 1, computed as a Morgan fingerprint Tanimoto coefficient. It measures shape, not effect.

Common questions

What is the difference between Cholecalciferol and Ergocalciferol?

These are vitamin D3 and D2 and they differ in a side chain, C27H44O against C28H44O. D3 is what human skin makes when ultraviolet B light hits 7-dehydrocholesterol, and it is also what comes from fish and lanolin. D2 is the fungal and plant version, made when the same light hits ergosterol, which is why ultraviolet-treated mushrooms are sold as vitamin D enhanced.

Is Cholecalciferol bigger than Ergocalciferol?

Ergocalciferol is the heavier molecule, 396.6 g/mol against 384.6 g/mol for Cholecalciferol. Cholecalciferol is C27H44O and Ergocalciferol is C28H44O.