Supplements have become standard-of-care treatment for dysregulated vitamin D metabolism without clear evidence that they sufficiently raise serum 25D levels to control elevated PTH.1 Real world data show that 25D levels are inadequate in most patients with CKD, despite customary treatment.2 Ineffective supplementation allows PTH to rise, prompting a switch to hormone treatment (e.g., oral calcitriol) and squandering the opportunity for early and more effective 25D repletion. This evidence concerns the gene PTH and chronic kidney disease.