I guess overall for worst case then, eliminating the 6 month time frame. Say after several years of TRT, you wanted to stop for some reason (cost, other health issues, not working, whatever the case may be). I'm having a hard time finding out what the possible permanent implications are from doing TRT. Natural production never "turning on", irreversible cardio issues, other? The benefits are all very well documented so I'm just curious about the possible negative outcomes. I probably get too analytical about this, but I'd hate to picture a future me frustrated that I didn't ask these negative based questions before I started. I've asked at the TRT clinics but they whitewash things.
Highly unlikely there would be any permanent negative consequences from trt.
Regarding the hpta in most cases you would just return to your previous natural baseline levels as it would be rare that there is dysfunction to the point that natural baseline levels are lower than before starting trt.....maybe in cases of men who use/abuse testosterone for bodybuilding purposes (cycling, blasting-cruising) using high doses long-term.
Regardless aging in and of itself can have a negative effect on the hpta and if your T levels are sub-par now they may very well be worse down the road.
Having healthy FT levels is critical to a man's overall health (physically/mentally).
Testosterone let alone it's metabolites estradiol and dht are responsible for the beneficial effects they have on mood/libido/erectile function/immune system/bone health/brain health/body composition.
Everyone always speaks of testosterone when in fact I would say it's metabolites estradiol and dht are more important as they are needed in healthy amounts in order to truly experience the full spectrum of beneficial effects.
Side-effects which can happen on trt the most common being increased hematocrit/hemoglobin, others such as oily skin/acne (genetically prone), male pattern baldness (genetically prone), increase psa when first starting (minimal and returns to baseline in most cases), increase body/facial hair, gynecomastia (genetically prone), water retention, possible lowering of HDL (usually from high doses of T),
testicular shrinkage, reduced fertility.
Regardless if one does experience any side-effects in most cases they can be minimized or eliminated by using ancillary medications let alone lowering T dose if ones testosterone levels were too high.
Aside from increased hemoglobin/hematocrit, reduced fertility and possible lowering of HDL (usually from higher doses of T) a majority of the side-effects would be cosmetic and even than it is not a given that one will experience such as genetics and how one reacts to said dose of T will play a big role.
If you went on trt and down the road decided to come off than if anything the only permanent sides would be the increased body/facial hair growth and hair loss if one was genetically prone and experienced such.
Regarding gynecomastia it is not common on trt and it would only happen in the genetically prone let alone if caught early it could be prevented.....worst case scenario is in cases where it is not caught early and treated with ancillary meds than surgery may be needed to have it permanently removed.
If your testosterone levels are sub-par and you are suffering from low-t symptoms than it would be in your best interest to get treatment as your overall health/quality of life should be priority!