This news story was Published Apr 09, 2019

A useful approximation of normal T levels in humans can be seen in present day hunter gatherers in Africa. The Hadza tribe was shown to have an average level of 151pmol/l, well below that of what we see in societies such as America. We can, therefore, argue that the reduction of T levels in modern man over the last few years is a shift back towards the norm.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2674347/#:~:text=Consistent with data from a,Hadza and the Datoga%2C respectively.