The powder is relatively cheap, so its not a big add on cost wise
Starting at a dose that is unlikely to produce any noticeable effects allows you to confirm that the injection process itself is tolerable, that you are not allergic to any component of the formulation, and that the compounding pharmacy provided what they claimed
How long is GHK-Cu stable after reconstitution
Agbo F, Isaacson SH, Gil R, Chiu YY, Brantley SJ, Bhargava P, Navia B (2021) Pharmacokinetics and comparative bioavailability of apomorphine sublingual film and subcutaneous apomorphine formulations in patients with Parkinsons disease and OFF episodes: results of a randomized, three-way crossover, open-label study
Because the vitamin is injected directly into the bloodstream, patients often feel results within hours to a few days