Research

Hormonal

Daily vitamin D supplementation (3,332 IU) for one year significantly increases total, bioactive, and free testosterone levels in overweight men with baseline vitamin D deficiency.

If you are overweight and have low Vitamin D levels, supplementing with 3,332 IU of Vitamin D daily for a year may significantly boost your testosterone levels. This effect was observed in men who were also losing weight, suggesting that correcting this specific deficiency is a valuable step for hormonal optimization in this demographic.

ModerateSupportsMEDIUM confidence
In the vitamin D group, however, a significant increase in all measures of testosterone status was observed. TT increased from 10.7 ± 3.9 nmol/l to 13.4 ± 4.7 nmol/l (p < 0.001), BAT from 5.21 ± 1.87 nmol/l to 6.25 ± 2.01 nmol/l (p = 0.001) and fT from 0.222 ± 0.080 nmol/l to 0.267 ± 0.087 nmol/l (p = 0.001).
Stefan Pilz et al. · Hormone and Metabolic Research · 2010

Why this rating

Randomized controlled trial design, but limited by small male subgroup size (n=54) and secondary outcome status.

Source

Effect of Vitamin D Supplementation on Testosterone Levels in Men

Stefan Pilz et al. · Hormone and Metabolic Research · 2010

DOI 10.1055/s-0030-1269854

rct · n=54Cited 330×
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DOI resolved against Crossref · corpus check 2026-06-10

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