This is a great thread, much appreciated you sharing your insights.
I'm 40-years old now but started out with secondary around 15/16. After years' of trying Clomid, Test-C + HCG, Test-C alone, I found myself last year getting the best results with monotherapy for a couple months before I run out of luck. Going to try the 300 miu/d dose like you now given your stated success. Was trying 500 miu EOD which worked for a bit before it went cold.
Did an E2 test last month and got 80 pgl/mL which is astronomical and twice the reference range of high. Did another one last week and got 39 pg/ml after scaling down my HCG dose to 300 from 500.
I believe the answer for me is also in the HCG and have not had luck on standalone Test-C beyond short intervals. E2 levels always around 30-40 pg/ml on 100 mg per week but don't feel the same way as I do with HCG - particularly with libido and sexual wellness, energy overall.
Would appreciate if you can continue sharing your results with us. Very tough to find someone in your/our position over so many years.
Overall I find HCG quite cyclical, meaning it works for a while then stops. But I stop using it for a couple weeks and go back, usually it works exceptionally well again before running dry a week or too later. Always thought it was E2 or potency from Pregnyl but have never been able to figure it out. Doing more blood work on my dime lately so hopefully can get some answers here.