Answer
It is vitamin D2. The body converts it into active metabolites that help control calcium and phosphate.
Sources for this answer
- Ergocalciferol 300,000IU Solution for Injection — Current selected SmPCemc · Summary of Product Characteristics
- UK GovernmentUK Government · Reputable Web
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.