> my question is...is there anything that will cause permanent chemical castration?
For the purposes of education:
"permanent chemical castration" only means that the functioning of the testicles will stop; there is no actual castration from chemicals.
That said, anything which stops the production of testosterone for a period of time, will leave the testes unable to once again start production.
This period of time is variable, like everything else;
This period of time is dependent on the strength and resilience of the individual's testes -- the individual personal genetics. etc.
For some people, this will happen quite quickly, for others it will take some time.
If a person stops a chemical castration program too soon, then yes, the testes could once again begin production of testosterone, albiet at a lower level.
One other thought on this:
chemical castration is in one sense like a born-woman having a hysterectomy --
The human body requires hormones from SOME source to simply function properly.
If a person removes, disables, or cripples any primary hormone source, it will become necessary for that person to use supplemental hormones for the duration of their life, for proper physical functioning.