The present study confirmed the reduction in the expression of adipogenic and an increase in myogenic modulators occur in human subjects taking T. More importantly, our results also suggest for the first time the potential role of enhanced PRDM16 in regulating these pathways perhaps directly or indirectly by unknown downstream targets which was never explored before, providing insights into a regulatory network that underpins the positive effects of T on body composition in men with hypogonadism. The gene discussed is PRDM16; the disease is hypogonadism.