CDC.

In the USA CDC supplied and pushed labs to use "their" range of numbers. When the CDC was asked for the information on how they arrived at the range....

Their test groups did not differentiate health/age/median/mean/health issues. So in short they threw poop up against a wall to see what would stick.

With that said my teaching while in the Navy was "Do not complain unless you have a solution to offer to fix the complaint". Here is my solution:

Range means jack when it comes to testosterone . If you want to put stock into a number then you need to qualify that number. To qualify the number it takes statistical research (mathmatical!). In general I would say it is more important to know the 5th and 95th percentile of a number range than the mean or median (average or most occurring) when it comes to testosterone.

Normal Testosterone Levels in Men by Age - Free and Total Healthy Male Ranges

This test shows us some very interesting items. First if you are 95th percentile you are 900-1000 your whole life. Do these 95th percentile people have issues from being 95th percentile? Do you hear of testosterone LOWERING therapy? I would say you are going to be hard pressed to get a documented case of a person with 900 TT that had "bad reactions" this range of test seeing how the only documented cases of this are on forums and not in laboratories.

Second is to look at the 5th percentile. This is where I get my opinions on this topic. If you take a group of men and do this test there is going to be a point in the range where the effects of low test kick in. Where is that? Without research it would be a guess. If I had to guess it would be 10th percentile and below. So I would make this statement:

If you are 10th percentile or below you are most likely a very strong candidate for TrT. I base this from statistical research and throwing out the top 10% and bottom 10% (or 5%) to strengthen the results of the test. So from a statistical point of view if you are 350-400 TT you should be on TrT or a program to raise your TT.

In Conclusion, it really gets my goat to see medical professionals telling 5th and 10th percentile people they have "no problem" and testosterone is not a consideration for any "issues" they have. It even gets on my nerves to hear...my testosterone is 4xx do you think I should naturally try to raise it before TrT? TrT is the only way youa re going to actually find out where your testosterone level makes you feel proper. So raise it naturally to what?

CDC is on my SH** list