How do you answer the critics that say the reason 25hydroxy levels are low is because the body is converting high quantities of 25hydroxy to the active form of D, calcitriol and that 25hydroxy vitamin D may block the effects of calcitriol Thanks!
Mackay I turned your question over to the council hoping they could give you a better answer, so more may get posted later.
I suggest reading https://www.vitamindcouncil.org/the-physiology-of-vitamin-d/. Science only thought Calcitriol was made by the kidneys and this is what they call “Endocrine” function. Later and more recently they discovered that it has an “Autocrine” function. “When other tissues in your body turn 25(OH)D into 1,25(OH)₂D, they make this activated vitamin D ‘inside and around cells’.” “Tissues like you brain, skin, breast, colon, cardiac muscle, immune cells, and more all make 1,25(OH)₂D with 25(OH)D.”
So there are two different systems and “the critics” statements do not make any sense. This is also why you need plenty of “raw” material. So your body can decide when and where it is needed and “convert” it where it is needed.