Vitamin D3 Calcifediol Monohydrate (25-OH-D3)

Vitamin D3 Calcifediol Monohydrate (25-OH-D3) (CAS 63283-36-3) is the principal circulating metabolite of cholecalciferol, formed by hepatic 25-hydroxylation of vitamin D3. A pre-activated intermediate on the biosynthetic pathway to the fully active form 1,25-dihydroxyvitamin D3.

Where is Vitamin D3 Calcifediol Monohydrate (25-OH-D3) used?

• Pharmaceutical: active substance in prescription and OTC formulations addressing vitamin D insufficiency
• Analytical: certified reference standard for clinical 25(OH)D3 assays and method development
• EU food supplements: authorised vitamin D source under Annex II of Directive 2002/46/EC, added by Regulation (EU) 2025/352
• Nutraceutical: crystalline and powder forms suit encapsulation, tablet compression and sachet formats
• EU health claims under Regulation (EC) 432/2012 cover calcium and phosphorus absorption, blood calcium levels, bones, teeth, muscle function, immune function and cell division.

Good to know: Carries a Danger signal word under GHS classification; potent steroidal compound precautions apply, including controlled-temperature storage, inert-atmosphere handling and personal protective equipment. Purity specifications typically align with Ph. Eur. or USP monograph requirements.

Commercial specifications

• Molecular weight approximately 400.6 Da
• Defined monohydrate stoichiometry
• 1 IU vitamin D activity corresponds to 0.025 mcg cholecalciferol equivalent
• 1–5 kg units for trials and pilot batches; 25 kg drums or cartons for bulk, with CoA, safety data sheet and regulatory support files