Well, for one thing that it doesn't go bad. If it's lost its potency I could deal with it, just don't want it to kill me! If tests show it's still even somewhat effective, I'll be a happy camper. I'm back training with or without it and started on TRT again, but I know I'll get better results with it. Looks like they charge $300 for HGH purity test. Cheaper than throwing out the whole lot and starting over, I guess.
So I'll keep this short since I'm sure you only want the bottom line.
You could go to any good AI and ask:
"I have a 6 year old vial of lyophilized rHGH that's sealed and been kept in cool storage. If an RP-HPLC test shows good purity, could that result be deceptive? What forms of degradation are likely to have occurred that would be missed and what does it mean for safety and bioactivity of the rHGH?"
And you'll get a list of things undetectable by the test that are likely to have happened over 6 years, and still allow for a high purity result on your $350 test(shipping).
TLDR even with high purity, actual potency is probably significantly reduced and some potential health risks could be present.
I know you probobly paid a small fortune for that stash, but you may not realize prices have dropped significantly. (quality has gotten better too, relative to what UGL was pumping out years ago).
So your other option is spend that $350 on 800+ IU of a fresh batch.