Vitamin D3 is one of the most popular daily supplements and it is associated with a number of health and performance benefits: increased cognition, immune health, bone health, muscle repair, recovery and muscle function.

Vitamin D3 deficiency is common in both the general public and athletic populations. This may be due, in part, to: living at far northern or southern latitudes, training indoors, protective clothing, sun-screen or consciously avoiding sun exposure.

All of these factors reduce the specific sun exposure required for the body to synthesize vitamin D3 and studies reporting positive effects of vitamin D3 supplementation often see benefit as a result of correcting deficiencies.