It has a critical role in regulating calcium and phosphorus absorption to improve bone mineral density, and bone mass, and reduce fracture risk. Another primary function is its role in boosting immunity, it goes as far as inhibiting carcinogenesis and treating COVID-19. Vitamin D has been also linked to improved heart health and reduced risk of cardiovascular diseases. It also plays a role in insulin sensitivity, insulin resistance, and appetite regulation.

Vitamin D plays a major role in neurotransmitter pathways to make serotonin and dopamine, hence why supplementation improves mood, anxiety, and depression, and even helps in the progress of patients with MS.