Does high dose vitamin D supplementation aid in muscle hypertrophy?

There are no official guidelines to assist in answering this question. I will search for relevant research papers instead.

From the Research

Vitamin D Supplementation and Muscle Hypertrophy

• The current evidence suggests that vitamin D supplementation may have a small positive effect on muscle strength, but its impact on muscle hypertrophy is less clear 1, 2, 3.
• A systematic review and meta-analysis of randomized controlled trials found that vitamin D supplementation had a small but significant positive effect on global muscle strength, but no significant effect on muscle mass or muscle power 1.
• Another meta-analysis found that vitamin D supplementation had a positive effect on lower-limb muscle strength in athletes, but not on upper-limb muscle strength or muscle power 2.
• A more recent meta-analysis found that vitamin D supplementation had no statistically significant effect on improving maximum strength and power in athletes, but highlighted the need for further research to address key limitations in previous studies 3.

Effects of Vitamin D on Skeletal Muscle

• Vitamin D is thought to play a role in skeletal muscle physiology, with effects on myocyte proliferation and growth 4.
• Vitamin D deficiencies have been associated with reduced muscle mass and strength, and supplementation has been shown to improve these parameters in vitamin D-deficient individuals 5.
• Vitamin D has been found to modulate skeletal muscle cell proliferation and differentiation, and to regulate protein synthesis and mitochondrial function 5.

Athletes and Vitamin D Supplementation

• Athletes with vitamin D deficiency may benefit from supplementation to improve muscle strength and reduce injury rates 4.
• Vitamin D supplementation has been found to be more effective in athletes trained indoors, and in those with lower baseline serum 25(OH)D concentrations 2, 3.
• However, the optimal dose and duration of vitamin D supplementation for athletes remains unclear, and further research is needed to determine the best supplementation strategies 2, 3.