Very recent paper from October 2022.
I'm not one to push for constant higher Free T levels or the idea that everyone 70 years ago was walking around with 1700ng/dL TT levels, but I thought this was interesting. They used equilibrium dialysis and a nonobese ("healthy") population of men, coming...
Abstract
The present study was designed to assess the responsiveness of the hypothalamic-pituitary-gonadal axis to kisspeptin administration with increasing age in men. Human kisspeptin‐10 was administered in a single iv bolus dose (1 µg/kg BW) to healthy adult, middle and advanced-age men...