Thanks for the advice. I already bought 60 days worth so we'll see if it helps. I'm in day 3. So far nothing different I can detect.
My last physical my testo was 684 with "free" at 12.1. I think that's pretty normal.
The "normal range" of testosterone levels (total and free) seems to vary from reference to reference.
The laboratory that measures my total testosterone cites a "reference interval" of 241 to 827 nanograms/deciliter. But I've come across references that range from 300 ng/dL (for the low end of "normal") to 1000 ng/dL (at the high end).
The situation for free testosterone appears to be less well defined. As I understand it, the only accurate measurement method is quite expensive and hence not generally used for routine free testosterone measurements. Instead, one of several substantially less expensive (but approximate) methods is used instead. Unfortunately, although the results from these various methods are generally internally consistent and reproducible within a single method, they may differ substantially from method to method. Hence it is often recommended that comparison with the "normal range" should be made using the collective set of measurements measured at the same laboratory as the sample under question.
For the particular laboratory that does my measurements, the "reference interval" for free testosterone (direct) is given as 6.6 - 18.1 pico-grams/milliliter (which would put you almost exactly in the middle of the range). But, by way of contrast, I've also seen a level of 60 pg/mL quoted as the upper end of the "normal" range for measurements from a different lab (methodology not stated).