Does Low Vitamin D Affect Testosterone?

Yes, low vitamin D can significantly impact testosterone levels in men. Research shows that men with vitamin D deficiency (below 20 ng/mL) have testosterone levels approximately 10-20% lower than those with adequate vitamin D status. Vitamin D acts as a steroid hormone precursor and influences the production of testosterone in Leydig cells within the testes. Studies involving over 3,000 men found that those with sufficient vitamin D levels (above 30 ng/mL) had significantly higher free testosterone concentrations. The relationship appears bidirectional, as testosterone may also affect vitamin D metabolism. Supplementation with 3,000-4,000 IU of vitamin D3 daily has been shown to increase testosterone levels by 13-30% in deficient men over 12 months.