Vitamin D Supplementation(!) Increases Testosterone in Men

Thanks to Dashforce from the MindAndMuscle-Forum we finally have evidence for the direct effect of vitamin D3 supplementation on testosterone in men. Dashforce reports on a study by scientists from Austria and Germany (Pilz. 2010) who provided 54 men, whose serum levels were previously at the lower range ~30ng/ml (the referential  minimum varies depending on which source you cite from 30-50ng/ml),with either 83 μg (3 332 IU) vitamin D daily or placebo for 1 year.

Table 1: Characteristics of the study groups at baseline and at the end of the study

As you can see in table 1,vitamin D supplementation lead to a significant increase in total testosterone from 10.7 nmol/l to 13.4 nmol/l. What's even more important, this increase (+25%) was not compensated by and an increase of SHGB, so that the amount of free testosterone rose from 0.222 n/mol to 0.267 nmol/l, i.e. by +20% (vs. +5% in the placebo group).

What is particularly interesting about this study is the fact that supplementation actually raised the level of testosterone. This is different from most previous studies, which observed a correlation between higher vitamin D levels and higher testosterone levels. If for example some probands would simply have been more healthy and thus exhibit higher levels of both, we would have had the same correlation. In the case of the Pilz study there is a clear causative effect between restauration of adequate vitamin D levels and increases in total and free testosterone.

I hope we see more trials with a similar design - also to investigate if there is a dose response relationship and whether even higher vitamin D levels would further increase testosterone. Until then, keep an eye on your vitamin D level and take a supplement to get to the upper ranges of the "normal" range ~80ng/ml.