I think every urologist should read this study before they put their patients on anti-androgenic drugs to treat BPH and early stage prostate cancer.
Low free testosterone levels predict disease reclassification in men with prostate cancer undergoing active surveillance - San Francisco - 2014 - BJU International - Wiley Online Library
"...These results suggest low levels of testosterone are associated with more aggressive prostate cancer. This contradicts long-held beliefs that high testosterone is risky for prostate cancer, and low testosterone is protective," said Dr. San Francisco. The results of this study provide valuable information to clinicians and their patients concerning risk factors for prostate cancer progression in men undergoing active surveillance. "In borderline cases, the presence of low values of free testosterone may help determine whether it is more prudent to initiate treatment rather than continue observation," said Dr. San Francisco."
Can you clarify some thoughts of yours on the biological activity of free versus bound testosterone?
I understand Ray has said with thyroid that the bound hormones have activity (perhaps even more than 'free' thyroid hormones) - but I wonder if the case is different for sex hormones. For example SHBG preferentially binds testosterone relative to estrogen - so in cases of elevated SHBG, men can sometimes suffer symptoms of excess estrogen (as in gynecomastia with hyperthyroidism).