I know this thread is a few months old but I found a little something worth reading. It appears that triptorelin is an analog of gonadorelin modified to increase its active life. Gonadorelin does the same thing but has a shorter active life and is released in a pulsatory manner requiring more frequent dosing.
"Triptorelin is a synthetic analogue of gonadorelin (natural GnRH decapeptide) with amino acid (D-tryptophan) substitution in position 6 to inhibit rapid degradation for long activity."
I was told you have to pin it daily so Triptorelin sounds like the better choice due to one time pinning only.