Vitamin D effects on androgen levels in men

Background. Accumulating evidence from animal and human studies suggests that vitamin D is involved in many functions of the reproductive system. Considering the potential link between vitamin D and human fertility, authors performed this review summarizing current literature on vitamin D and possible mechanisms explaining the link of vitamin D with androgen metabolism in men. The purpose of this review was to provide an overview on the effects of vitamin D on androgen metabolism in men. Methods. Author performed a systematic literature search in PubMed for relevant English language publications published from January 2011 until September 2021. Results. The vitamin D receptor and vitamin D-metabolizing enzymes are found in reproductive tissues. In men, vitamin D status has been associated with androgen levels and hypogonadism. Further, there is some evidence for a favorable effect of vitamin D supplementation on testosterone concentrations, although others failed to show a significant effect on testosterone levels. Vitamin D might play an important role in androgen metabolism. Existing evidence from available trials evaluating the effect of vitamin D supplementation on androgen levels in men is insufficient to recommend measurement of 25(OH)D levels or vitamin D supplementation in hypogonadal men. We cannot exclude vitamin D effects on androgen levels in men with low TT levels or in men with severe vitamin D deficiency. This question remains to be answered in future investigations. Conclusions. Vitamin D deficiency is associated with adverse fertility outcomes including hypogonadism, but the evidence is insufficient to establish causality. High-quality trials are needed to further evaluate the effects of vitamin D supplementation on androgen levels in men.