Answer
Calcitriol is the active hormonal form of vitamin D. Unlike colecalciferol, it does not require kidney activation before acting.
Sources for this answer
- NHSNHS · NHS medicine guidance
- Calcitriol 0.25 mcg Soft Capsules — Current selected SmPCemc · Summary of Product Characteristics
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.