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