Three weeks into GHK-Cu subq and I’ve had a persistent red welt at every injection site. Not hot, not painful, doesn’t spread - just an obvious red circle about the size of a quarter that hangs around for 10-14 days before fading. Wanted to document this bc I couldn’t find much on timelines from people actually injecting it rather than using it topically. Context: I’m post-sleeve (2017) and have been on tirzepatide since march 2024, so I’m no stranger to subq injections. My tirz sites clear in 2-3 days max. GHK-Cu is a different story. What I was doing initially: 2mg in 3mL BAC water, 29g 1/2 inch needle, abdomen. Switched to a 31g 8mm needle thinking smaller gauge might help - still red. What actually reduced the duration was slowing my injection rate way down (like 30 seconds for a small volume) and letting the syringe sit until truly room temp before injecting. I was probably injecting slightly cool solution before. Current sites stay red about 7-8 days now instead of 12-14. Still more than I expected. Hypothesis: copper has local vasodilatory effects, and subq tissue responds differently than dermis. The topical data doesn’t translate well to predicting injection site behavior. Anyone with post-WLS loose skin using this subq - curious if your sites run longer than average too, or if that’s just me.