Longish post concerning problems with low libido (most likely due to low dopamine levels) even after testosterone is fixed.
Quick history on me. I'm taking medication for hypothyroidism and low testosterone levels. My thyroid numbers have been good for a couple of years now. After a year or so of trying Androgel, then HCG alone, then testosterone cypionate alone, then testosterone cyptionate + HCG, I think at least my testosterone and estrogen numbers are balanced. Yet another blood test in less than a week will confirm whether this is the case.
One thing that hasn't really changed is seemingly low or mediocre libido, sex drive, etc. It's better than it was when my testosterone levels were below range, but probably still low for a healthy, fit 40 year old, and I've had associated ED problems off and on for a couple of years. These issues haven't been great for relationships. I've tried Viagra and similar drugs, but they only affect the vascular system to increase blood flow to the penis, and then seemingly only if testosterone and estrogen levels are okay. They don't do anything to increase libido, which is centered in the brain and nervous system. Consequently, results were not always great with the blue pill and equivalents.
About a year or so ago I had a blood test that measured various catecholamines:
norepenephrine: 345 pg/mL [range 0-399]
epinephrine: 44 pg/mL [range 0-99]
dopamine: <10 pg/mL [range 0-142]
catecholamine: <399 pg/mL [range 0-642]
Clearly dopamine is quite low. My doc had me try cabergoline for awhile, but I didn't see much (if any) effect, so we stopped that to focus on straightening out testosterone levels. My understanding is that low dopamine levels adversely affect sex drive.
I recently became curious about whether Melanotan II or Bremelanotide (PT-141) might be of benefit, so I ordered some Melanotan II and started injecting at 0.5 mg/day at bedtime (I'm 6'2" and weight about 190lbs). I experienced greatly enhanced sex drive within a few hours, in addition to much firmer and consistent morning erections. I was actually concerned about the duration of the erection when I woke up at 2:30am the first morning, so I stuck a flexible cold pack in my shorts to ensure blood had a chance to circulate.
The increase in sex drive was sufficiently distracting to lower my Melanotan II dosage level to 0.35 mg/day. Around the same time I had to start taking Prednisone (steroid based anti-inflamatory) for a minor nerve impingement problem, and Prednisone's myriad side effects seemed to counteract the Melanotan II benefits. However, after tapering off of the Prednisone over the past few days, my sex drive seems to be back in high gear - - - sufficiently so that I might lower my Melanotan II dosage level again.
I seem to have a very dramatic response to the Melanotan II at a very low dosage level, at least compared to other people. I'm wondering if that has anything to do with my low dopamine levels? I have a technical background, but it's not in chemistry or biology, so I don't really know what mechanisms are at work here.
Any thoughts or comments would be appreciated.