testosterone is normally measured in nanograms per deciliter (ng/dL.) Normally functioning adult male testicles produce an average of 7mg of testosterone per day, 1 milligram = 1,000,000 nanograms 1 liter = 10 deciliter There are 5 liters of blood in the average adult male body. This means that the average male "total testosterone" output into the bloodstream is: 7,000,000ng / 50 dL = 140,000 ng / dL total testerone per day. Therefore, using an often accepted 800ng/dL "reference" measurement for "optimal" testosterone, it could be proven that the assay is revealing 1/175th of the total daily testosterone output. Further, this means that in the theoretical model of the optimal male described above, the total point-in-time reading of 800mg/dL of testosterone is completely metabolized by the body 175 times per day. 800ng/dL in a 5L volume of blood is equivalent to: 800 ng / 1 dL = 40,000 ng / 50 dL = .04 mg / 5L = 0.04mg total testosterone in the bloodstream. at the time of assay. 0.04mg * 175 cycles = 7mg total testosterone produced by the testicles per day. Testosterone metabolism appears to be quite rapid! Thoughts? Problems with the math?