This is purely for curiosity sake and to address what could be an enormous blind spot in my own comprehension.
According to the internet, the consensus seems to be > 300 ng/dl is considered low.
So our hypothetical, otherwise healthy man, returns a result of 299 and jumps on 250mg (this seems to be a number common among TRT bros) of test enanthate per week.
As far as I know, any amount of exogenous will eventually tank natural production, correct? So after a month or two, hasn’t our man has effectively lowered his test score from 299 to 250?
I get this is ridiculously simplistic example of a complicated subject, but I’m just trying to get a grip on what may be at times ‘less than completely honest’ accounts of results dosages vs actual reality.
Good to hear from you again, and great question! First, a few nuances though.
Testosterone deficiency (TD) is not established just with a lab value, but rather laboratory evidence and symptoms not otherwise attributed to something else. There will be people above and below 300 ng/dL with and without TD, though 264 ng/dL is the most generally accepted cut off right now based on updated tests and population data for T. Labs also vary.
In any case, the half life of the ester attached to T in your example (enanthate) is ~ 5-10 days. With most TRT administered weekly (250mg would be on the higher end), T levels in the blood “stack” on top of one enought. This accumulation continues over multiple half-lives until the rate of new drug input (the weekly injection) equals the rate of drug elimination, i.e. “steady state”. This usually takes a half dozen half lives or so.
At steady state, the testosterone levels will still fluctuate with a peak right after the injection and a trough (lowest point) right before the next injection, but the overall average concentration of testosterone in the blood will be consistently higher than what a single dose provides on its own.