Clinical Benefits and Adverse Effects of Genetically-Elevated Free Testosterone Levels: A Mendelian Randomization Analysis
August 2019
TLDR Higher free testosterone levels can increase bone density and decrease body fat but may raise the risk of prostate cancer, hair loss, and benign prostate enlargement.
In 2019, a Mendelian randomization analysis was conducted on 136,531 white British males from the UK Biobank to determine the effects of genetically-predicted calculated free testosterone (CFT) on 23 health outcomes. The study found that each 0.1 nmol/L increase in genetically-predicted CFT was associated with increased heel bone mineral density and decreased body fat percentage. However, it also led to adverse effects such as an increased risk of prostate cancer, androgenic alopecia (hair loss), benign prostate hyperplasia (BPH), and increased hematocrit percentage. The study concluded that long-term elevated free testosterone levels cause prostate cancer, BPH, and hair loss while reducing body fat percentage and increasing bone density. It also found that these levels have a neutral effect on type 2 diabetes, cardiovascular and cognitive outcomes.
