So supposedly the hormonally active form of D3 in the body is Calcitriol or 1,25 Hydroxyvitamin D3. Thus it begs the question, why don't we see any calcitriol supplements on the market?
It does seem to exist as a prescription however under various brandnames. Eg Vectical.
And tangentially has anyone considered tracking both 1,25 and 25(OH) D (Calcidiol) levels?