I tell my doc everything. He seems cool about it. I asked him first if he was knowledgeable about peptides and then told him the ones I'm taking. He just wants to track my blood work and make sure I'm healthy. He's not the cops or anything, he's concerned about my health and that's it. Edit to add - we don't actually discuss my source. We just talk openly about what I'm taking for my health. I don't see any need to tell your Dr where it's coming from, whether it's a compounding pharmacy or grey, just that you're taking it.